Molds And Heat

[joeb33050]

Molds and Heat
I made a picture of how I think the alloy/bullet and mold heat and cool in the casting cycle, while casting "good" bullets.
The alloy in the pot is hot, the mold is empty and cooling.
The pour starts, the alloy in the mold cools as the mold heats up. At some point the bullet and sprue are solid, at some point the mold and the spout are separated. Either can be first.
The bullet in the mold and the mold cool.
The mold is opened, the bullet comes out of the mold.
The mold continues to cool.
The alloy in the pot is hot, the mold is empty and cooling.
And so on.
I'll try to attach the picture.
We go through a lot of gyrations casting bullets.
Sometimes we cool the mold or sprue plate on a wet surface between castings, a la Bruce B or Dick Howes or A.C. Gould.
Sometimes we cool the mold, empty or full, with a fan.
Sometimes we wait a long time for the mold to cool before opening the sprue plate.
Sometimes we heat the mold on a hot plate.
Sometimes we put the mold in the alloy to heat it up, while casting.
Some of us say the old "Every mold is different, only trial and error will teach you how to cast with a given mold." The old "there are too many variables to ever understand how it works" business.
I think that there are only two things we can vary in bullet casting, the temperature of the pot and time. Temperature is easy, but time has several components.
Time the spout is in contact with the sprue plate or is keeping a molten puddle of alloy on the sprue plate.
Time between moving the mold from the spout and opening the sprue plate.
Time between removing the bullet and closing the sprue plate and starting the next pour.
Aside from the temperature and time variations are the wet sponge, fan, hot plate businesses.
Time has some value to us, even to old retired guys like me. I'd like to cast good bullets faster, that's what most of the gyrations are about.
The gyrations are necessary because there's an imbalance between the alloy freezing temperature and the mold dimensions.
If the mold is too small, it has to be cooled down.
If the mold is too big, it has to be heated up.
A small mold example is my Ohaus 45-405 mold that casts 45 caliber 433 grain bullets. It is 1" X 1.25" X 1.4" high with a sprue plate 1" tapering to .5" X 1.5".
This mold needs a lot of cooling time.
A big mold example is my custom made 30 caliber mold casting a 185 grain bullet. It is 1.38" X 1.25" X 1.6" high with a sprue plate 1.25" tapering to 1" X 1.86" long. A heavy mold with a big thick sprue plate, it needs the pot running wide open and dipping in the alloy every 2-3 bullets to cast good bullets.
Another big example is the Eagan 58 grain 22 caliber mold, that took a lot opf heat and a lot of time to cast good bullets.
During the casting process molds cool off more than I'd ever expected, from ~500-550F to ~250-350F between solidification and re-pouring. Molds are excellent heat dispersers. Heat dispersion with molds of a given material, iron or brass or aluminum in still air, at room temperature is a function of the total heat in the mold and the surface area of the mold.
If the mold is going to cast a great big bullet, the mold needs to be big.
If the mold is going to cast a small bullet, the mold needs to be small.
Mold size, for maximum casting speed, is a function of bullet weight, and maybe dimension ratios, but certainly of bullet weight.
This relationship is easily understood, I think, and easy to define.
What's the practical application, you (Pat) ask? If we understand the relationship, we can devise ways to build molds of the proper size, modify existing mold sizes, and/or insulate or enhance surface heat transfer.
I think that a too-big mold can be made smaller with an increase in casting speed.
I think that a too-small mold can be increased in surface area with an increase in casting speed.
Is this wrong? Or, is it time for some experiments?
joe brennan

[joeb33050]

The chart, maybe.

[joeb33050]

Another try at the chart. Is it me?

[Springfield]

You do have some valid points. I like to cast with 2 LEE 6 cavity moulds for the best use of my time. I have found that, in general, moulds with bullet cavities larger than 200 grains work OK. Smaller than that and you really have to move in order to keep the moulds hot enough. Too much larger than that, 300 grains or larger, and you really have to slow down or the bullets are too hot and break on hitting the towel, or smear when opened. I have tried using the wet towel but it is hard to be consistant. I just had this thought reading your post that maybe I should add some cooling fins(heat sinks?) to some of my moulds. Might work better than the wet rag, and should be more consistant.

[leftiye]

Joe,
How would a mold heater (used during the casting cycle) affect the need for proportionally sized mold blocks relative to the shape/volume of the cavity?

[kodiak1]

2 six bangers and the old 90 pounder at 750 plus and lets get to work and make a serious pile of those little silver projectiles.
Not to fussy if the start to come out a little on the frosty side either.
Ken.

[454PB]

The biggest alloy/mould temperature challenge I have is a Lee 500 gr. .45 caliber single cavity and at the other end an RCBS 55 gr. .224 double cavity. Running these two moulds back to back demonstrates exactly what you're saying.

I have to cool the Lee with every fill, and keep a torch going to keep the RCBS hot.

[joeb33050]

I spent a lot of last night thinking about this. I think that for the mold that is too small, that gets and stays too hot, that some might cool on a wet sponge or in a fan; maybe a BIG sprue plate would increase cooling speed. We're talking BIG.
For a mold that is too big, that takes a long time and a lot of heat and dunking in the alloy to make it cast good bullets; maybe reducing the size of the sprue plate would reduce the amount of heat dissipated.
Ric in Yakima suggests coating the mold with grill paint to reduce heat loss.
I cut the handle-part of a sprue plate on an Eagan mold way down, and it helped, although not enough.
Another alternative is to cut off a lot of the mold material.
I think the ideal is like my SC 311299 or my past SC 429421 that would cast good bullets as fast as I could operate the mold and dipper.
I'm going to measure some molds, but now I have to go shooting.
joe brennan

[joeb33050]

Joe,
How would a mold heater (used during the casting cycle) affect the need for proportionally sized mold blocks relative to the shape/volume of the cavity?

I'm still thinking about this.
I'm talking about a situation where good bullets are being cast, the process is underway and working. Not heating up the mold to get ready to cast.
We need a mold heater when the mold is too big, when it gets rid of more heat and lowers the temperature below where good bullets are made.
Assume that the pot temp has been turned up and fiddled with, and that varying the pot temp doesn't fix the "cold mold" problem.
Also assume that the speed of casting has been increased to the practical limit. Hanging around with the mold open cools it down, we need to get the bullet out, mold and sprue plate closed and the next pour made.
We can fix this "cold mold" problem by using a mold heater, or by changing the mold.
Changing the mold includes changing the sprue plate, changing the dimensions of the mold = cutting some metal off, insulating the mold.
I don't have a lot of hope for the insulating, but I'm often wrong.

For a hot mold, the time taken to let the mold cool slows the casting process. It would be nice to go faster. I'm thinking that the "hot mold" problem is/may be easier to fix. I'm thinking that a really BIG sprue plate might fix the problem, by acting as a BIG radiator and surface area to get rid of the heat and cool the mold quickly. Changing the sprue plate doesn't change the mold, everything goes together as it was.

Then I'm thinking that I approach the start up wrong. I let the mold heat up on the edge of the pot, at least 45 minutes. Then the first or second bullet is good, and I feel proud. But that ain't the ideal situation. The ideal situation is that the pour, open sprue plate, open mold, drop bullet, close mold, close sprue plate cycle happens without any/much waiting and the bullets are good.
Maybe I need to set the mold at a lower temp, let everything heat up, cast the mold at a lower temp, make some bad bullets, eventually get the mold hot and working ideally.

And I'm thinking of asking for information on molds so that we can start to understand how this works.
I'm still thinking.
joe brennan

[montana_charlie]

For a hot mold, the time taken to let the mold cool slows the casting process. It would be nice to go faster. I'm thinking that the "hot mold" problem is/may be easier to fix. I'm thinking that a really BIG sprue plate might fix the problem, by acting as a BIG radiator and surface area to get rid of the heat and cool the mold quickly. Changing the sprue plate doesn't change the mold, everything goes together as it was.
My idea for curing the 'hot mould' is 'fins'.

You know that the slots cut in the sides of the mould for the handles are at a safe distance from the cavity wall.
Close together saw cuts, parallel to and no deeper than those handle slots, would resemble the fins on a heat sink designed to remove heat from a sensitive item (like an electronic part).

Two cuts above and two cuts below the handle slot...on each side of the mould...would start the configuration. Need more cooling, add cuts.
They can even be deeper at the mould corners.

Leave enough stock for the handle mounting screws to thread into...and don't make the cuts with the screws in place...!

On the subject of 'letting it ride'...
Given a choice of being saddled with a mould that runs hot...or one that runs cool...I would prefer the 'hot' mould.

I much prefer the idea of just slowing down (to provide mould cooling time), more than the thought of having to 'do something extra' to keep one hot enough.

On the subject of which kind of mould will be 'hot' versus 'cool', I still don't have a clear picture of what you believe...

Using moulds for a 500+ grain .45 bullet as examples:
The Lyman 457132 is a 'small' iron mould.
The NEI 348A (same bullet) is a 'big' aluminum mould.
My Victory PGT is made of iron, and as large as the NEI (with a very similar cavity size).

How would your thinking classify these three when trying to predict which will run 'hot'?

CM

[joeb33050]

Some molds are "hot", they require some cooling off between pours. We wait for the cooling of, or have a fan blowing on the mold, or use the Bruce B, Dick Howes, A. C. Gould method of cooling the mold on a wet sponge or pad. These molds are too hot. An example is the Ohaus 45-405, a 45 caliber 433 grain SC mold..
Some molds are just right, normal unhurried and un-slowed cycling through the casting operation gives us good bullets, fast.
Some molds are "cold", they require quick casting or dipping the mold in the lead or heating on a hot plate or operating at a high pot temperature or a combination of these or other "fixes". If you stop for a bit you get wrinkled bullets. These molds are too cold. An example is the custom #78-185, a 185 grain 30 caliber SC mold.
I took a sample of molds, only iron/steel molds because I don't want to deal with brass or aluminum now. No Hoch molds because the geometry is so different from Lyman/RCBS/NEI/Ohaus molds.
I measured the length, width and height of the molds.
Sprue plates all covered the mold top, and then hung over some amount. I traced the overhang onto graph paper and used that to estimate the overhang area.
I measured the bullet length, estimated a representative bullet weight, put it all in a spreadsheet, and calculated the mold surface area.
Then calculated bullet grains per square inch of mold surface area.
Then calculated the mold plus overhang surface area; and bullet grains per square inch of that surface area.
The Ohaus mold had the largest number of grains of bullet weight per square inch of mold or mold/sprue area, at 49.71 and 42.65 grains per square inch.
The #78-185 mold had the smallest number of grains of bullet weight per square inch of mold or mold/sprue area, at 15.56 and 12.73 grains per square inch.
The Ohaus mold is too hot because it has too much lead going into too small a mold.
The #78-185 mold is too cold because it has too much surface area on the mold and sprue plate for the size of the bullet.
I've attached the WORD copy of this with the table.
I'm looking for data on iron molds for both smaller and larger than 30 calibers. Or any caliber, including light 30s.

Sprue Tot
L W H Area B Length B Wt. Gr./"^2 plate area Area Gr./"^2
#78-185SC 1.25 1.38 1.61 11.89 1.13 185.00 15.56 1.32 14.53 12.73
358495SC 0.98 1.20 1.36 8.28 0.60 148.00 17.87 0.33 8.94 16.55
308403SC 1.01 1.19 1.37 8.40 0.88 170.00 20.23 0.33 9.06 18.76
308241SC 0.98 1.19 1.36 8.21 0.90 170.00 20.70 0.33 8.87 19.16
311299SC 0.95 1.19 1.36 8.06 1.20 208.00 25.81 0.33 8.72 23.86
31141DC Sam Anderson Sprue Plate 1.23 1.38 1.49 11.15 0.98 170.00 30.50 0.84 12.83 26.51
311291DC Modified 1.38 1.23 1.38 10.57 0.88 170.00 32.16 0.57 11.71 29.03
314299DC 1.24 1.39 1.48 11.18 1.18 205.00 36.69 0.57 12.32 33.29
429421DC 1.24 1.38 1.48 11.12 0.77 248.00 44.60 0.57 12.26 40.45
45-405SC 1.00 1.26 1.38 8.71 1.09 433.00 49.71 0.72 10.15 42.65

[joeb33050]

I can't attach an .xls or .doc file here, if you're interested, just send a message and I'll attach both.
joe brennan
joeb33050@yahoo.com

[joeb33050]

If you'll send me the info on the iron molds and bullets, I'll forecast how they cast. Need length, width, height of molds, bullet weight, SC or DC ; to start.
I'm recording all suggestions including yours re fins.
joe brennan




My idea for curing the 'hot mould' is 'fins'.

You know that the slots cut in the sides of the mould for the handles are at a safe distance from the cavity wall.
Close together saw cuts, parallel to and no deeper than those handle slots, would resemble the fins on a heat sink designed to remove heat from a sensitive item (like an electronic part).

Two cuts above and two cuts below the handle slot...on each side of the mould...would start the configuration. Need more cooling, add cuts.
They can even be deeper at the mould corners.

Leave enough stock for the handle mounting screws to thread into...and don't make the cuts with the screws in place...!

On the subject of 'letting it ride'...
Given a choice of being saddled with a mould that runs hot...or one that runs cool...I would prefer the 'hot' mould.

I much prefer the idea of just slowing down (to provide mould cooling time), more than the thought of having to 'do something extra' to keep one hot enough.

On the subject of which kind of mould will be 'hot' versus 'cool', I still don't have a clear picture of what you believe...

Using moulds for a 500+ grain .45 bullet as examples:
The Lyman 457132 is a 'small' iron mould.
The NEI 348A (same bullet) is a 'big' aluminum mould.
My Victory PGT is made of iron, and as large as the NEI (with a very similar cavity size).

How would your thinking classify these three when trying to predict which will run 'hot'?

CM

[montana_charlie]

If you'll send me the info on the iron molds and bullets, I'll forecast how they cast. Need length, width, height of molds, bullet weight, SC or DC ; to start.
Well...if you want real numbers, I would need to use examples that I actually own.
The three I posted were just 'generic' examples, except for the Victory mould.

Otherwise, mine are all SC, large block NEI aluminum jobs, which you are not yet ready to deal with.

But, the dimensions on the (ferrous metal) Victory PGT are:

Length - 1.72"
Width - 1.48"
Height - 1.91" (including .195" sprue plate)
Bullet Wgt. - 550 grains
Single Cavity

Sprue Plate handle overhang - .815" x .955"

I haven't used this mould, yet. So your prediction should prove interesting when I do...
CM

[joeb33050]

But, the dimensions on the (ferrous metal) Victory PGT are:

Length - 1.72"
Width - 1.48"
Height - 1.91" (including .195" sprue plate)
Bullet Wgt. - 550 grains
Single Cavity

Sprue Plate handle overhang - .815" x .955"

I haven't used this mould, yet. So your prediction should prove interesting when I do...
CM

I get 34 grains of bullet per square inch of mold surface, not counting the .195" sprue or its overhang.
From the limited data I have, this mold is on the hot side, around my 314299DC, which takes a while to harden and cool.
I predict that you'll have to wait a while for the bullet to harden, that your casting pace will be slower than you'd like. This is a "hot" mold.
My 45-405 is at ~50 grains per inch squared and is VERY SLOW to use.
joe brennan

[montana_charlie]

Thanks, Joe, for running those numbers through your brainstorm.
If you are correct, it will reach operating temp quickly, and I will be able to cast at a leisurely pace that allows plenty of time for noticing details.

Additionally, I should be able to run the alloy at a 'low' temperature that produces frost-free bullets and retards oxidation in the pot.

We'll see if the proof is in the pudding...
CM

[joeb33050]

We have a volunteer for the machine work on, first, the "hot" mold. It needs more surface area, and more weight. I mailed the mold yesterday, asked him to make a new BIG sprue plate ~2" square, and plates to go on the bottoms of the molod halves, held on with the handle screws and needing also "no-rotation" screws.
I've updated the EXCEL file with some mold weights. Ask and I'll send it.
joe brennan

[joeb33050]

The biggest alloy/mould temperature challenge I have is a Lee 500 gr. .45 caliber single cavity and at the other end an RCBS 55 gr. .224 double cavity. Running these two moulds back to back demonstrates exactly what you're saying.

I have to cool the Lee with every fill, and keep a torch going to keep the RCBS hot.

Could/would you tell me about the RCBS mold. I need measurements of length = parallel to the handles, width across the two halves, height of the mold less the sprue plate;;;then an estimate of the area of the sprue plate overhang-the part extending beyond the mold. I trace it on a piece of graph paper and count the squares. Also need the weight in ounces, the lady at the post office is happy to weigh them for me.
Thanks;
joe brennan

[joeb33050]

But, the dimensions on the (ferrous metal) Victory PGT are:

Length - 1.72"
Width - 1.48"
Height - 1.91" (including .195" sprue plate)
Bullet Wgt. - 550 grains
Single Cavity

Sprue Plate handle overhang - .815" x .955"

I haven't used this mould, yet. So your prediction should prove interesting when I do...
CM

CM, could you tell me the weight of this mold? The post office lady weighs mine, ounces and tenths.
I'm eagerly awaiting your casting session.
Thanks;
joe b.

[BruceB]

The farther I am from doing things mathematical, the happier I am. Been that way since grade school, and it's not about to change after 60 years.

HOWEVER, as I've said before, it's endlessly interesting to see the methods and findings you more-scientific lads can come up with. This thread is yet another example.

An analogy comes to mind, regarding MY use of such calculations as are being discussed here. In mining, a bonus system is often used to reward productivity on a monthly basis. We have a whole department of people working all month to calculate the bonus for the next payday, based on tons skipped, feet of advance, number of rockbolts installed, tons trucked, DOZENS of possible factors are entered. At the end of all the calculating, there's a strong possibility that some manager will come along, look at the final tightly-calculated bonus figures, and say "Naw, that won't do, we are gonna pay THIS figure"...and with a stroke of the pen he will void the entire month's work for the bonus department. (Had an example just yesterday....the calculated bonus for August was "rumored" to be about $8 per hour worked, but it was finalized "by management" at $9.63.)

So, even while I'm aware of, and impressed by, the fine figuring done on threads like this, my moulds "do the talking" and calculations count for nothing. My temps are pretty consistent once the casting session is underway, because the rhythm is consistent. Same amount of fill time, same amount of wet-pad-contact-time, same amount of empty-mould time, and consistent melt temperature as well. Once the routine is established and functioning, I HATE to break the rhythm for any reason at all. Large blocks or small, aluminum or iron, I can make decent bullets with any of my moulds...as long as I PAY ATTENTION. I suspect that my cycle time, from dropping the bullet to the NEXT dropping of the bullet, doesn't vary by more than a second or two.

Keep it up, guys, I'm constantly learning stuff here!

[sundog]

Ah, yes. The ole BruceB Speed Casting Academy! Right on, bro.

Crank up the heat. If you get frosted boolits or have to wait too long to cut the sprue, back off a little. Then settle into a rhythm. It ain't rocket science (but durn close).

[TAWILDCATT]

me thinks you all do to much thinking and not enuf casting.what in heavens name did us old timers do to make bullets.I have made bullets in remington molds colt molds ideal and lyman also M&B and lee and saeco.I have cast by dipper, bottom pour and Gilbert caster/miller.you all are making it into working slavery.my god enjoy yourselves not suffer.
-----------:coffee: -----:Fire: ---------:coffee: -----:confused: -------[smilie=1:

[leftiye]

Ya know, it's all probly pretty simple. For a given alloy, a given mold will cast well at some given temp. That is, if there's no goop, mold release, or anything in the cavities, and the mold is made of a certain metal, there's a temp range at which it can be predicted to cast well.

The heat conductivity of the block metal, and the alloy are, I think the determining factors. The mass, and shape of the mold blocks, and the volume and shape of the cavity(ies) will also affect this, but I'd guess it to be less than the operating range of the mold. What you need is an infra red thermometer ($20 at Harbor fart), and a heat source that will allow you to control mold temp. This will allow you to control block temp, and minimixe the effect of the cooling rate of the given blocks, and boolit weight/cooling.

[454PB]

Could/would you tell me about the RCBS mold. I need measurements of length = parallel to the handles, width across the two halves, height of the mold less the sprue plate;;;then an estimate of the area of the sprue plate overhang-the part extending beyond the mold. I trace it on a piece of graph paper and count the squares. Also need the weight in ounces, the lady at the post office is happy to weigh them for me.
Thanks;
joe brennan

Here you go, Joe:

RCBS 22-055 FN

Mould 1.746" long
1.254" wide
1.499" tall

Sprue plate:

1.467" by 1.751" by .131" thick The tab on the sprue cutter is .880" by .880", for a total area of 3.342 Sq. inches. I don't have a scale that will weigh in ounces, and none of my reloading scales go over 1000 grains.

Hope this helps

Another variable to throw at you......

Years ago I made a bunch of aluminum sprue cutters for my steel moulds. It does seem to help remove heat from large caliber moulds.

[**oneshot**]

When I cast I do not cool my mould or my sprue plate, I just try to keep a good tempo to keep my bullets consistant. I get great results as long as I do my part throughout the cycle.

[joeb33050]

Here you go, Joe:
RCBS 22-055 FN
Mould 1.746" long
1.254" wide
1.499" tall
Sprue plate:
1.467" by 1.751" by .131" thick The tab on the sprue cutter is .880" by .880", for a total area of 3.342 Sq. inches. I don't have a scale that will weigh in ounces, and none of my reloading scales go over 1000 grains.
Hope this helps
Another variable to throw at you......
Years ago I made a bunch of aluminum sprue cutters for my steel moulds. It does seem to help remove heat from large caliber moulds.

If I did the numbers correctly this mold is close to impossible to cast with. Calculating bullet grains per square inch of mold surface gives 8.23. Ric has a mold that calculates 14.19 and he has trouble with it. I have a custom mold that calculates 15.56, I have to dip it in the alloy, cast fast and still get a lot of defective bullets.
These are what I call "cold" molds, there's too much iron for the lead.
A second calculation is grains per square inch of mold area plus sprue plate overhang area. Yours is 7.37, Ric's 12.19, mine 12.73. Again, I don't see how you get any good bullets from this mold.
Would you consider getting this mold weighed at the post office? I need the weight in ounces and tenths, with screws and sprue plate, for the third calculation.
Thanks;
joe brennan

[joeb33050]

The farther I am from doing things mathematical, the happier I am. Been that way since grade school, and it's not about to change after 60 years.

HOWEVER, as I've said before, it's endlessly interesting to see the methods and findings you more-scientific lads can come up with. This thread is yet another example.
So, even while I'm aware of, and impressed by, the fine figuring done on threads like this, my moulds "do the talking" and calculations count for nothing. My temps are pretty consistent once the casting session is underway, because the rhythm is consistent. Same amount of fill time, same amount of wet-pad-contact-time, same amount of empty-mould time, and consistent melt temperature as well. Once the routine is established and functioning, I HATE to break the rhythm for any reason at all. Large blocks or small, aluminum or iron, I can make decent bullets with any of my moulds...as long as I PAY ATTENTION. I suspect that my cycle time, from dropping the bullet to the NEXT dropping of the bullet, doesn't vary by more than a second or two.
Keep it up, guys, I'm constantly learning stuff here!

When casting with a given alloy, there are two and only two initial things that we can vary to affect the quality of the bullets. We can vary the pot temperature, and vary the casting speed-and what we vary here is the length of time we wait between pour and open-the-mold. Only two things.
The second order things we can vary help us to make cold molds hotter or hot molds cooler. For instance, from "The Modern American Rifle" A. C. Gould, copyright 1891: "...Before commencing, place a dish of water near you, and a mallet or stick of wood; the first to plunge the mold into when it is growing too hot,..."
Now A. C. is talking about a "hot" mold. And what he's doing is cooling the mold off so he can cast faster, so he can get more bullets per hour.
This is all about bullets per hour.
Some molds will cast good bullets as fast as you can go through the operations, no, that's NO waiting time between pour and open-the-mold.
Many molds operate in a satisfactory manner as we vary the pot temperature.
Then there are molds that require cooling with a fan or water or wet cloth or ...; and molds that require heating by dipping in the alloy or being on a hot plate or in a torch flame.
I think that there's a relationship between mold size and bullet size/weight and the mold's casting characteristics. I think that if I can get some more data from you guys that we can find out what this relationship is.
I think that we can devise add-ons for hot molds that will turn them into ideal molds. And I think that we can get the mold manufacturers to have more than one size of blocks-probably three sizes would work- that would allow ideal operation.
So, for once at least, I've got a practical application for all this number crunching in mind.
joe brennan

[sundog]

Two is rather finite. Myopic. As far as I'm concerned there are other things. Mould condition, cleanliness, prep stuff like Bullplate or release agent, venting, block alignment, sprue plate adjustment, sprue hole diameter, lubrication. And here's the one some may not agree with me on, but I have proven to myself for many years, year after year. Atmospheric conditions. I make my very best boolits on cool and damp or rainy days. Crunch all the numbers you want. I'll rely on just cranking up the pot and do what works.

[felix]

Without doubt, Sundog is right on. He actually means a condensing atmosphere is best to cast in, in a manner such that moisture drops out of the sky and lands on the mold between fills. Why this works best is unknown by me. Just cooling the mold with wet rags is just not the same. Success is measured by the consistency of a batch of boolits. ... felix

[montana_charlie]

CM, could you tell me the weight of this mold? The post office lady weighs mine, ounces and tenths.
I'm eagerly awaiting your casting session.
Thanks;
joe b.
This Victory mould weighs 19.6 ounces, Joe.

I have plenty of bullets waiting to be loaded, so I wasn't planning to use this mould in the near future. But, in the interest of this experiment, perhaps I'll de-grease it and give it a try in the next few days.

I would like to see if it casts as beautifully as the 'loaner' from Victory that I made these bullets with...


Two is rather finite. Myopic.
He said "two initial things" and left an opening for "the second order things".

Perhaps it could be called myopic to focus on 'mechanical considerations' when the discussion is one about 'temperature relationships'.

Mould condition, cleanliness, prep stuff like Bullplate or release agent, venting, block alignment, sprue plate adjustment, sprue hole diameter, lubrication.
Bullplate, release agent, and lubrication are 'foriegn substances' on the mould.
As such, you get to decide if they should be there, or cleaned off. That makes them fall under your 'cleanliness' heading, and cleanliness is not really a 'variable'. A guy does it...or doesn't.
But even so, they are 'mechanical' in that they prevent damage to the mould, or make bullets drop out easily. The quality of what falls out is not governed by the coating that makes it fall.

Except for sprue plate adjustment (still a 'mechanical' thing) the others are not things we 'vary' to affect bullet quality. Sprue holes and venting can be enlarged, but not made smaller. So they really aren't 'variables'.
That only leaves 'block alignment' which is a feature of 'mould condition'. If alignment is incorrect, it can be rectified, modified, or villified...but it's not something you vary back and forth to tweak your bullet quality.

Atmospheric conditions. I make my very best boolits on cool and damp or rainy days.
Finally...a factor which can affect mould and alloy temperature. Your myopia seems to be fading...
CM

[Dye]

Joe
When we cast a bullet all we are doing is changing a liquid to a solid. Alloys
all have different freeze temperatures. A mould is nothing but a form tool,
just like a ice cube tray. We a forming in the mould cavity,so if we keep the
mould cavity at a constant temperature the bullet will be constant. I have found about 100-150 above freeze temp for the alloy and 300-350 for the mould cavity
This is for 1or 2 cavity moulds ,I dont use 6 cavity moulds for target shooting. I take from your post that you don't have a I-R therometer.I wil donate you one if you will P-M me a mailing address. It will not be a Raytec or a Fluke but will pick one up at Harbor Freight. They do work and will give you a better idea on the mould cavity temperature, not the outside of the mould

Be carefull Dye

[joeb33050]

This Victory mould weighs 19.6 ounces, Joe.

I have plenty of bullets waiting to be loaded, so I wasn't planning to use this mould in the near future. But, in the interest of this experiment, perhaps I'll de-grease it and give it a try in the next few days.

I would like to see if it casts as beautifully as the 'loaner' from Victory that I made these bullets with...
CM

I've got to revise my forecast due to additional information. This Victory mold is on the hot end, but not too hot, not too close to the serious problem molds.
I think it will still be hot and take some time for the sprue to harden, but not be horrible.
It's beginning to look like hot and cold molds are affected more by mold weight than by mold surface area.
Still, more info is needed, particularly on molds that are very cold or hot in use.
Thanks;
joe b.

[joeb33050]

My idea for curing the 'hot mould' is 'fins'.

You know that the slots cut in the sides of the mould for the handles are at a safe distance from the cavity wall.
Close together saw cuts, parallel to and no deeper than those handle slots, would resemble the fins on a heat sink designed to remove heat from a sensitive item (like an electronic part).

Two cuts above and two cuts below the handle slot...on each side of the mould...would start the configuration. Need more cooling, add cuts.
They can even be deeper at the mould corners.

Leave enough stock for the handle mounting screws to thread into...and don't make the cuts with the screws in place...!

CM
Ken has my hot, so-hot-it's-a-pain-to-use Ohaus 450405 mold. I've asked him to make a BIG sprue plate and pieces to fit on the bottoms of the mold halves-held on with the handle screws and kept from rotating with a shelf or screw or pin.
It starts to look like hot molds are associated with light weight for the bullet size. I'm thinking that add-on pieces such as mentioned above will add weight and surface area to the mold, and make it run closer to ideal.
I think there are two things going on; the AMOUNT of heat the mold can absorb, and the SPEED at which the mold can get rid of the heat. Both are connected with size, weight varying as the cube of dimension and surface area varying as he square.
Fins would increase surface area and heat transfer, but reduce weight. And, for me the hobbyist, add-ons are possible but machining is not.
Fins might be the the solution for cold molds, put on by the manufacturer, but making the mold smaller is the simplest solution-I think.
Still thinking
joe b.

[Bret4207]

I think that we can devise add-ons for hot molds that will turn them into ideal molds. And I think that we can get the mold manufacturers to have more than one size of blocks-probably three sizes would work- that would allow ideal operation.
So, for once at least, I've got a practical application for all this number crunching in mind.
joe brennan

Joe- I'm all for improvements and I'm not trying to rain on your parade, but we can't get Lee to make a mould to size or Lyman to bring back any useful designs. And you want 3 different block sizes!?!? Methinks there's some windmill tilting at hand.

Best of luck. I admire your perseverance.

[Jim]

As a mechanical(read air conditioning) pipefitter, I need to have a good grasp on heat transfer in order to do my job and know how to solve problems that come up in my day-to-day work. I ain't no Veral by a long shot(no pun intended) but, at the risk of wavin' my own flag, I DO know heat transfer.

I use Lee molds exclusively, not because they're better'n any other brand but, because I can afford 'em. These puppies are made outa aluminum and aluminum can be a PITA or VERY user friendly if you know it's "language".

I put up with waiting for the mold to cool down a little for months before it dawned on me one day "You moron, think about heat transfer!". I drug out one of my older and more worn out molds and began to study the block halves. I quickly realized I could DOUBLE the surface area of the blocks, thereby transfering the heat to atmosphere(theoretically?) twice as fast.

I removed the sprue plate and gently clamped the blocks in the vice using cardboard as jaw lining. I put a new blade on my hack'emup saw and cut a groove into the block, the depth being about equal to the width of the cut. That triples the area of the surface that was actually grooved. If you put grooves all the way around the blocks, that doubles the surface area. I know that what I just said seems self contradicting, but ya' gotta get a picture of the area multiplied and do the math.

Anywho, I took the time to cut grooves all the way around the blocks and now it's got a lot of little fins. The mold, by the way, is an old .458-405- HB. I fired up the pot and let the mix get good and hot. I put the mold on the mix a little longer than I usually do to get the mold hot. I started casting and after the mold heat/casting speed ratio balanced out, it took me about 10 or 12 casts to realize it was not taking near as long for the sprue to solidify, allowing me to dump a lot faster.
I have NOT gone off the deep end and cut grooves in all my molds. However, I HAVE cut grooves in a few choice older of the larger molds. When I do use them, I'm gettin' a lot more boolits per hour than I usta.

That's my story an' I'm stickin' to it.

[44man]

Now Jim, you done gone and ruint all them molds. The only solution is for you to send me all of them to scrap for ya, course I have to test them first. [smilie=1:

[sundog]

MC, your are right about 'foreign substances'. However, some moulds require all the help they can get to make consistently good boolits. Yes we have the choice. There's more than just adjusting the temp or when to break the sprue. It's a 'big picture' kinda thing. We have a lot of control.

[Jim]

44, I dun tested 'em and they is all ruint, sure enough. Ain't no sense in spendin' good money fer shippin', seein' as ain't no need fer you to do sump'm I is already dun.

I love this forum.

[Bass Ackward]

The biggest problem we have in every step of the cast bullet process is the correct diagnosis of a problem. We see it here all the time. One step is taken to correct or compensate for something or the lack of something else. If the variables are fixed, then you must adapt.

I have been given a one cavity LBT mold of a 230 grain olgival wadcutter in 44 caliber. All my past experience with his molds have been two cavities. After trying every trick in the book from opening the sprue hole to improve venting and flow rate, this mold is impossible to cast unless you are at 800 degrees and 850 is better, regardless of mix or smoke in the cavities. And you still need to cast like a madman. You can forget frosting without going up in temp which my RCBS pot won't do. Two bullets in this same block size and material would have allowed normal casting temps and rates.

1. So mold size does matter. 2. Or block material does matter. 3. Or lead volume does matter and thus the temperature of that lead. Or your casting rate if you can't control variables one and two.

[montana_charlie]

Anywho, I took the time to cut grooves all the way around the blocks and now it's got a lot of little fins.
You seem to have proved my theory...but did it a little differently than I would have.

Many shallow grooves take longer to create than (say) two deep ones. But both can result in the same amount of metal removed from the mould, and might produce the same increase in surface area.

If you make two saw cuts .25" deep (about the same depth as the slots for the handles) which are separated by the width of your saw blade...you create one 'fin' but you have lengthened the (top to bottom) surface area of that side of the block by (essentially) 1 full inch. The amount of metal weight removed is probably too small to consider.
Taking those two cuts clear around the mould causes an enormous amount of extra surface for air to suck heat from.

The position of the fin might also make a difference in 'how' the alloy cools. My guess would be to place it above the handle slot...but who knows what's best?
Perhaps vertical fins would be better...
CM

[Single Shot]

me thinks you all do to much thinking and not enuf casting.what in heavens name did us old timers do to make bullets.I have made bullets in remington molds colt molds ideal and lyman also M&B and lee and saeco.I have cast by dipper, bottom pour and Gilbert caster/miller.you all are making it into working slavery.my god enjoy yourselves not suffer.
-----------:coffee: -----:Fire: ---------:coffee: -----:confused: -------[smilie=1:

YOU GOT THAT RIGHT.

Since getting seriously ill and fully disabled, I was selling THOUSANDS of bullets on E-Bay using stock LEE 6 cav molds and some ORIGINAL SAECO and IDEAL.

MANY BECAME DIRECT BUY CUSTOMERS often ordering 4000 BOOLITS every few months. When I told them what size company I was (1-man) and that it would take awhile. They just increased their lead time for me. When I sent out a E-mail stating that I could not cast for a while because of a severe car crash, the replies were. DON'T WORRY. THOSE ACCURATE BULLETS ARE WORTH WAITING FOR.

It is not about a complicated sophisticated control process. It is simple about DOING IT THE SAME WAY ALL THE TIME.

CONTROLLED POT TEMP BY WATCHING A THERMOMETER, FILLED POT, LET TEMP STABILIZE TO WHAT I HAD LISTED as a starting point for the mold I was using. AND RAN UNTIL POT EMPTY so I could take a break while next pot was heating.

Just touched the base of a lee mold to a damp cotton towel like they suggest to cool it.

Used my own lube formula.

[montana_charlie]

It is not about a complicated sophisticated control process. It is simple about DOING IT THE SAME WAY ALL THE TIME.
Full agreement. Consistent casting produces consistent results...which can be consistently good, or consistently bad...depending on the caster.

But, how does consistency alone correct a problem with a mould which always runs too hot, or too cold?

I haven't been troubled by that phenomenon (I don't think), but that is what the discussion is about.

CONTROLLED POT TEMP BY WATCHING A THERMOMETER,
Certainly, that is the first consideration...especially for the 'hot' mould. But, some of the members seem to have trouble getting their pots to go high enough to keep a 'cold' mould working right.

The discussion seems to be focused (right now) on the 'hot' mould, and your solution for that is the damp towel.
I tend to agree with your customers...the ones who say that "accurate bullets are worth waiting for". So my solution is simply to slow down the rhythm.

But, you and I both know that some will prefer to 'build in' a fix for any difficulty that arises...or at least try to understand 'why' a particular difficulty exists.
So Joe is hot on the trail of 'why' does a mould run hot or cold, and the rest of us are playing along with ideas for 'remedies'.

Does your bullet casting business experience provide you with the insight to put forth any theories for reaching that goal?

CM

[MT Gianni]

As a mechanical(read air conditioning) pipefitter, I need to have a good grasp on heat transfer in order to do my job and know how to solve problems that come up in my day-to-day work. I ain't no Veral by a long shot(no pun intended) but, at the risk of wavin' my own flag, I DO know heat transfer.

I use Lee molds exclusively, not because they're better'n any other brand but, because I can afford 'em. These puppies are made outa aluminum and aluminum can be a PITA or VERY user friendly if you know it's "language".

I put up with waiting for the mold to cool down a little for months before it dawned on me one day "You moron, think about heat transfer!". I drug out one of my older and more worn out molds and began to study the block halves. I quickly realized I could DOUBLE the surface area of the blocks, thereby transfering the heat to atmosphere(theoretically?) twice as fast.

I removed the sprue plate and gently clamped the blocks in the vice using cardboard as jaw lining. I put a new blade on my hack'emup saw and cut a groove into the block, the depth being about equal to the width of the cut. That triples the area of the surface that was actually grooved. If you put grooves all the way around the blocks, that doubles the surface area. I know that what I just said seems self contradicting, but ya' gotta get a picture of the area multiplied and do the math.

Anywho, I took the time to cut grooves all the way around the blocks and now it's got a lot of little fins. The mold, by the way, is an old .458-405- HB. I fired up the pot and let the mix get good and hot. I put the mold on the mix a little longer than I usually do to get the mold hot. I started casting and after the mold heat/casting speed ratio balanced out, it took me about 10 or 12 casts to realize it was not taking near as long for the sprue to solidify, allowing me to dump a lot faster.
I have NOT gone off the deep end and cut grooves in all my molds. However, I HAVE cut grooves in a few choice older of the larger molds. When I do use them, I'm gettin' a lot more boolits per hour than I usta.

That's my story an' I'm stickin' to it.

Fluted moulds, like a barrel? Gianni

[leftiye]

I think that if I had a mold that got too hot, and didn't cool down fast enough I'd set it on a heat sink (reads piece of aluminium) for a controlled amount of time each cast before I'd machine fins in it. Just my (lazy) opinion. Much easier, and you can mess with either the size, etc of the heat sink and/or the time. Reverse this if the mold can't be gotten hot enough- set it on a heat source during each cast. Of course, if things can be gotten to work without the delay, then just control heat with the alloy temp.

[joeb33050]

I think that if I had a mold that got too hot, and didn't cool down fast enough I'd set it on a heat sink (reads piece of aluminium) for a controlled amount of time each cast before I'd machine fins in it. Just my (lazy) opinion. Much easier, and you can mess with either the size, etc of the heat sink and/or the time. Reverse this if the mold can't be gotten hot enough- set it on a heat source during each cast. Of course, if things can be gotten to work without the delay, then just control heat with the alloy temp.

But wouldn't it be better if the mold cast perfect bullets as fast as you could operate it, without the delay for letting it cool down or putting it on the aluminum plate? By the way, I can get my molds to cool down pretty quick by putting the mold down square on my upside down muffin tin-ingot mold. I put it right on a muffin bottom. But, wouldn't it be..........
joe brennan

[leftiye]

Yup, It would be nice, especially if it weren't too much work or too much expense. So, how much metal will I have to take off of my single cavity Lyman .22 cal (225438) 43 grainer to get it hot enough?

[joeb33050]

Yup, It would be nice, especially if it weren't too much work or too much expense. So, how much metal will I have to take off of my single cavity Lyman .22 cal (225438) 43 grainer to get it hot enough?

If you will tell me the length(parallel to the handles), width across the two halves, and height of the mild; the area of the sprue plate overhang in square inches, and the weight of the mold with screws and sprue plate, I'll tell you how much weight to remove.
A sc Lyman 22 mold is probably 1" X 1.2" X 1.36", the sprue plate probably overhangs 3/4" and has an area estimated by tracing it on graph paper and counting squares of .33" squared. it probably weighs 6.6 ounces on a post office scale. If these numbers are ~ correct, this is a HORRIBLE mold to cast with, requiring a blow torch to get it hot enough and keep it hot so good bullets can be cast. To get it into the ideal range it would need to weigh a third to a half what it weighs now.
If I did the numkbers right.
joe brennan

[HORNET]

leftiye,
I would say that you need to remove all the weight by placing it in a box and sending it to me. I have very little trouble with the single cavity thast I have for that 225238 or the 2- cavity RCBS 22-055-FN or even the old 225462 HP. You use a little higher melt temperature and you can cast fairly quickly for a long time without them overheating. I did make new sprue plate out of 1/8" aluminum (with smaller openings) and can usually hold very tight weight ranges with a 50/50 mix of ww and lino.
On the other hand, I've got an old Lyman 2-cavity 375446 (the 265 gr gas check boolit) that only has about 1/8" between the cavities and overheats in a heartbeat....

[joeb33050]

leftiye,
I would say that you need to remove all the weight by placing it in a box and sending it to me. I have very little trouble with the single cavity thast I have for that 225238 or the 2- cavity RCBS 22-055-FN or even the old 225462 HP. You use a little higher melt temperature and you can cast fairly quickly for a long time without them overheating. I did make new sprue plate out of 1/8" aluminum (with smaller openings) and can usually hold very tight weight ranges with a 50/50 mix of ww and lino.
On the other hand, I've got an old Lyman 2-cavity 375248 (?- the 275 gr gas check boolit) that only has about 1/8" between the cavities and overheats in a heartbeat....

I find this fascinating. Another shooter tells me that the RCBS 22-055-FN requires a torch to keep it hot enough to cast. I think any Lyman SC 22 mold requires a lot of heat to cast well, torch or hot plate or dipping the mold in the melt or ?? This end of the range the problem isn't overheating, it's getting the mold hot enough to cast good bullets. And keeping it that hot.
I shot 375248 for years but had a SC Lyman mold.
Maybe it's the aluminum sprue plates.
My custom big mold is big, but the numbers aren't like the 22 Lyman numbers.
I think you should post all the info on these molds for inclusion in the data base.
joe brennan

[LiquidLead]

You guys are gonna scare the crap out of any newbies lurking around here. :mrgreen:

But, FWIW, I reserve the right not to disagree with none of the statements not made here :lol:

Mike

[HORNET]

O.K., Joe,
The numbers that I come up with for the RCBS .22-055-FN match those given by 454PB in post#24 - 1.50 x 1.252 x 1.740 with a weight of about 13 Oz., with the stock steel sprue plate. [My postal scale seems to have been hijacked (again) so I had to use my 25# capacity alloying scale which only reads in ounces.] The aluminum sprue plate knocks about 3/4 oz. out of total system weight, has 0.090 diameter sprue holes (Surprised me, I thought they were bigger), and matches the shape of the steel one. Sprue plate area is about 3.348 square inches. The weight checks about 13 ounces for several other RCBS molds that I checked and I think that you should be able to assume that the dimensions are RCBS standard.
The 1 cavity Lyman/Ideal blocks are much smaller at 1.353 tall, 1.190 across the parting line, and 0.990 long with a weight of about 7 oz. This is essentially the same for all 6 of the .22 molds measured. The aluminum sprue plates are 1-7/8 x 0.990 with a 1/4 x 1" notch for the stop pin, a weight of about 1/2 oz., and 0.102 diameter sprue holes. These have an area of about 1.606 square inches.
The 2 cavity Lyman #375449 checks out at 1.480 tall, 1.375 across parting line, 1.230 long and a weight of about 10 ounces. The actual distance between cavities checks at 0.040" by my calipers- extremely thin in my opinion.
Hope this helps,

[montana_charlie]

A sc Lyman 22 mold is probably 1" X 1.2" X 1.36", the sprue plate probably overhangs 3/4" and has an area estimated by tracing it on graph paper and counting squares of .33" squared. it probably weighs 6.6 ounces on a post office scale.
To get it into the ideal range it would need to weigh a third to a half what it weighs now.
Joe, I'm starting to get a little bumfuzzled.

I gave you the numbers for my big, beefy .45 cal. mould, and you said it would be a 'hot' one. You describe this little SC Lyman .22 as a 'cold' one.
My Victory weighs twice as much as the Lyman, yet you say the Lyman needs to be reduced by one third to a half to make it a 'warmer' mould.

Did you mean increased by a third or half?

Seems to me, if you reduced it by half, you'd have nothing left but the cavity and sprue plate.

CM

[joeb33050]

Joe, I'm starting to get a little bumfuzzled.

I gave you the numbers for my big, beefy .45 cal. mould, and you said it would be a 'hot' one. You describe this little SC Lyman .22 as a 'cold' one.
My Victory weighs twice as much as the Lyman, yet you say the Lyman needs to be reduced by one third to a half to make it a 'warmer' mould.

Did you mean increased by a third or half?

Seems to me, if you reduced it by half, you'd have nothing left but the cavity and sprue plate.

CM

Charlie;
I'm calculating three things. Maybe not the right things, but......
Bullet grains per square inch surface area of the mold
Bullet grains per square inch surface area of the mold and sprue plate overhang
Bullet grains per ounce of mold weight
Your Victory mold numbers are 34, 33 and 28. I keep the spreadsheet sorted, this mold is on the hot end, up around my 314299 that takes a while to harden and that I sometimes cool with artificial means.
My Ohaus 45-450 mild njumbers are 50, 43 and 68. This mold is HOT!!!
The 43 grain Lyman SC mold numbers are 5, 5 and 7. This means that there is a lot of mold for the bullet size, way lower than the next, RCBS 22-055FN DC, reported as needing a torch to keep it hot, at 8, 7 and I don't know because I don't have the mold weight.
It is all about mold surface area and weight vs. bullet weight. A ten pound mold with a 10 grain bullet is cold, you'll never cast good bullets. A 10 pound mold with a 14,000 grain bullet will need a lot of cooling.
Does this make sense?
I don't know if it does, I think it does, but need more data including mold weights.
joe brennan

[montana_charlie]

Does this make sense?
I can't say what makes sense, but at least I know which way your numbers are leading you.
I've been smoothing corners on my PGT mould this evening. I think tomorrow I will sizzle it for a while in the ultrasonic cleaner, then see how it casts...if I don't get sidetracked by anything else.

May have an 'opinion' soon for you about whether it's hot or not.
CM

[joeb33050]

I have at least partial data on 18 molds now. There are three variables calculated:
Bullet grains / mold surface area (grains/square inch)
Bullet grains / mold + sprue plate overhang surface area (grains/square inch)
Bullet grains / mold weight (grains / ounce)

It looks like the three variables track together, pretty well; so perhaps any of the three is a reasonable variable to talk about. So, Bullet grains / mold surface area (grains/square inch).

This varies from 8 to 50, rounding off.
At the 8 end we have cold molds that require a hot pot, a torch, a hot plate, fast casting, dipping the mold in the alloy or some other help. These molds tend to make a lot of wrinkled bullets.

At the 50 end we have hot molds, that require a long wait for the bullet to harden, air blowers, wet-pad-cooling, aluminum plate cooling or some other help. These molds tend to be quite slow in operation.

I still need some more information, particularly about iron or steel molds that are hot or cold.

I just got an RCBS 308-165-SIL DC mold with the variable of 25; this mold should be about ideal, casting good bullets about as fast as I can operate it.

joe brennan

[joeb33050]

O.K., Joe,
The numbers that I come up with for the RCBS .22-055-FN match those given by 454PB in post#24 - 1.50 x 1.252 x 1.740 with a weight of about 13 Oz., with the stock steel sprue plate. [My postal scale seems to have been hijacked (again) so I had to use my 25# capacity alloying scale which only reads in ounces.] The aluminum sprue plate knocks about 3/4 oz. out of total system weight, has 0.090 diameter sprue holes (Surprised me, I thought they were bigger), and matches the shape of the steel one. Sprue plate area is about 3.348 square inches. The weight checks about 13 ounces for several other RCBS molds that I checked and I think that you should be able to assume that the dimensions are RCBS standard.
The 1 cavity Lyman/Ideal blocks are much smaller at 1.353 tall, 1.190 across the parting line, and 0.990 long with a weight of about 7 oz. This is essentially the same for all 6 of the .22 molds measured. The aluminum sprue plates are 1-7/8 x 0.990 with a 1/4 x 1" notch for the stop pin, a weight of about 1/2 oz., and 0.102 diameter sprue holes. These have an area of about 1.606 square inches.
The 2 cavity Lyman #375449 checks out at 1.480 tall, 1.375 across parting line, 1.230 long and a weight of about 10 ounces. The actual distance between cavities checks at 0.040" by my calipers- extremely thin in my opinion.
Hope this helps,

The RCBS 22-055-FN, how does that cast with the steel sprue plate? With the aluminum sprue plate?
The 1 cavity Lyman 22. Pick 1. Bullet weight? What is the area in square inches of the OVERHANG of the steel sprue plate? Aluminum? How does it cast with each?
The 375449-what is bullet weight? Area sprue plate overhang, steel and alum.? How does it cast with each?
This is the data I need, keep it coming!!
Thanks;
joe brennan

[montana_charlie]

I have at least partial data on 18 molds now. There are three variables calculated:
Bullet grains / mold surface area (grains/square inch)
Bullet grains / mold + sprue plate overhang surface area (grains/square inch)
Bullet grains / mold weight (grains / ounce)

It looks like the three variables track together, pretty well; so perhaps any of the three is a reasonable variable to talk about. So, Bullet grains / mold surface area (grains/square inch).

This varies from 8 to 50, rounding off.
Got it...I'm starting to see the relationships you are following.

When I first gave you dimensions on my Victory PGT mould, you came back with...
"I get 34 grains of bullet per square inch of mold surface, not counting the .195" sprue or its overhang.
From the limited data I have, this mold is on the hot side,"

After telling you the weight of that mould, you still called it 'somewhat hot', but didn't specify a new 'number'. So, I was still going with the '34' from your earlier prediction.

Now, using my calculator to apply one of your ratios..."Bullet grains (550)/ mold weight (19.6)", I come up with a '28' for a number. Does this agree with your revised prediction?
If so, it is not far from the '25' on one of your moulds that you consider to be 'just about right'.

If this ratio - bullet weight/mould weight - turns out to be as good as (or better than) the other two you are watching...it would become a simple matter for a caster to know, from the start, how he will probably have to treat any particular mould that catches his eye.

It could also clarify a statement from the guy who says he has to run his pot at 1100° to avoid wrinkles in his "Teacup .222 HP".

When he posts that his 'number' works out to be '7', we would know that he has a 'cold one'...and not just go away thinking he's a frustrated pyromaniac.
CM

[joeb33050]

Got it...I'm starting to see the relationships you are following.

When I first gave you dimensions on my Victory PGT mould, you came back with...
"I get 34 grains of bullet per square inch of mold surface, not counting the .195" sprue or its overhang.
From the limited data I have, this mold is on the hot side,"

After telling you the weight of that mould, you still called it 'somewhat hot', but didn't specify a new 'number'. So, I was still going with the '34' from your earlier prediction.

Now, using my calculator to apply one of your ratios..."Bullet grains (550)/ mold weight (19.6)", I come up with a '28' for a number. Does this agree with your revised prediction?
If so, it is not far from the '25' on one of your moulds that you consider to be 'just about right'.

If this ratio - bullet weight/mould weight - turns out to be as good as (or better than) the other two you are watching...it would become a simple matter for a caster to know, from the start, how he will probably have to treat any particular mould that catches his eye.

It could also clarify a statement from the guy who says he has to run his pot at 1100° to avoid wrinkles in his "Teacup .222 HP".

When he posts that his 'number' works out to be '7', we would know that he has a 'cold one'...and not just go away thinking he's a frustrated pyromaniac.
CM
For your mold the grains per square inch of the molod was 34, grains per square inch of the mold plus sprue plate overhand was 33. Both of these numbers were 15th, on the hot side. The grains per ounce of mold weight number was 28. Now this is only 7th, this at 19.6 ounces. Now 28 is between my 308403 and 308241 molds, both about ideal-I can cast as fast as I want and get good bullets. So two measures give HOT and one gives IDEAL. I suspect that it will be WARM, some waiting will be required. But, I've got only a little data, and not many weights at all. I'm going to invent a HOT, WARM IDEAL, COOL COLD scale and start ranking these molds and asking others to rank theirs.
I'm going to write RCBS and Lyman asking for molds to cobble up, maybe adding smaller or larger or aluminum sprue plates will help.
As an aside, my new RCBS 308-165-SIL could easily be drilled with some big holes front to back!!!
NEED DATA!!!
joe brennan

[montana_charlie]

Here is some 'data' on the PGT mould, Joe.

I laid it on a hotplate set at 300° so it could be warming while I got my pot ready to go. Had to melt the contents, then flux...well, you know...
On the hotplate, it reached about 190° and stayed there while the plate's surface temperature stayed very close to 300°.

Ambient temperature was about 60° with a slight draft, but no wind.

When the pot was prepped, the 20:1 alloy was at 800° by my Lyman thermometer. So, I turned the heat down and set the mould on the edge of the pot to stabilize while the alloy got down to 750°...my preferred temperature.

Using an infrared thermometer (that tops out around 550°) I monitored all of the surfaces I could get readings from without going over it's range. The pot edge stayed somewhere above 450°, while the dipper floating on the alloy got up around 510°.

I forgot to check the mould temp when I started to pour, but I'm guessing it was about 200-250. The first six bullets were visual rejects, but the seventh was almost good enough. Just a tiny ding on the top edge of the baseband.

I cast a total of ten bullets in that first string...without checking temperatures...just to get some good ones. The final three were.

I put the mould on the pot edge, and added all of my sprues back in while fluxing the pot. Probably spent about five minutes doing the 'maintenance'. When the alloy was clean, and back up to 750° I cast ten more.

Of these, only the first one was slightly flawed.
I found that taking enough alloy out for twenty of these 550 grainers, drops the level in the pot by a good two inches. When it gets down that far, the pot temperature works it's way up to 800°...something I never paid attention to, because I don't usually keep the thermometer in the pot. It kinda gets in the way of my dipping...

The rhythmn I was using was casting about as fast as I could while not hurrying...and waiting about three seconds for the sprue to freeze...then another five before cutting the sprue.
I got no frost at that speed, even when the pot got up to 800°.

Before the third run of ten, I did the maintenance and added some fresh alloy along with the sprues.
All ten of the last bunch came out visually good, and I monitored the mould temp by holding it over the infrared unit at different stages of each pour.

It would read about 290° most all the time except when I had dropped the bullet, closed the plate, and checked it before going back to the pot.
During that short period, it would creep up around 315°. So it seemed to be hotter after the bullet was gone, than when it was still inside.

More careful measuring might produce a less confusing result, but that's what I got.

Anyway, I wouldn't call this a 'hot' mould.
I can cast at a comfortable pace, and don't feel 'delayed' waiting for the sprue to mature. It seems to spend most of it's time just below 300° and produces a smooth, shiney bullet the Lone Ranger could pass off as a silver one.

It doesn't appear to lose much of it's 'proper' heat while maintenance is going on, and quickly gets up to temperature if it is a bit cool.

I'm happy.

Hope the 'data' helps fill out your spreadsheet...
CM

[joeb33050]

CM
If you're waiting 3 then 5 seconds to open the sprue plate, I'd call this mold WARM at least. But, don't pay any attention to that.
On a scale of HOT WARM IDEAL COOL COLD, about making good bullets fast, where would you rate the mold?
Anyone else?
Thanks;
joe brennan






Here is some 'data' on the PGT mould, Joe.

I laid it on a hotplate set at 300° so it could be warming while I got my pot ready to go. Had to melt the contents, then flux...well, you know...
On the hotplate, it reached about 190° and stayed there while the plate's surface temperature stayed very close to 300°.

Ambient temperature was about 60° with a slight draft, but no wind.

When the pot was prepped, the 20:1 alloy was at 800° by my Lyman thermometer. So, I turned the heat down and set the mould on the edge of the pot to stabilize while the alloy got down to 750°...my preferred temperature.

Using an infrared thermometer (that tops out around 550°) I monitored all of the surfaces I could get readings from without going over it's range. The pot edge stayed somewhere above 450°, while the dipper floating on the alloy got up around 510°.

I forgot to check the mould temp when I started to pour, but I'm guessing it was about 200-250. The first six bullets were visual rejects, but the seventh was almost good enough. Just a tiny ding on the top edge of the baseband.

I cast a total of ten bullets in that first string...without checking temperatures...just to get some good ones. The final three were.

I put the mould on the pot edge, and added all of my sprues back in while fluxing the pot. Probably spent about five minutes doing the 'maintenance'. When the alloy was clean, and back up to 750° I cast ten more.

Of these, only the first one was slightly flawed.
I found that taking enough alloy out for twenty of these 550 grainers, drops the level in the pot by a good two inches. When it gets down that far, the pot temperature works it's way up to 800°...something I never paid attention to, because I don't usually keep the thermometer in the pot. It kinda gets in the way of my dipping...

The rhythmn I was using was casting about as fast as I could while not hurrying...and waiting about three seconds for the sprue to freeze...then another five before cutting the sprue.
I got no frost at that speed, even when the pot got up to 800°.

Before the third run of ten, I did the maintenance and added some fresh alloy along with the sprues.
All ten of the last bunch came out visually good, and I monitored the mould temp by holding it over the infrared unit at different stages of each pour.

It would read about 290° most all the time except when I had dropped the bullet, closed the plate, and checked it before going back to the pot.
During that short period, it would creep up around 315°. So it seemed to be hotter after the bullet was gone, than when it was still inside.

More careful measuring might produce a less confusing result, but that's what I got.

Anyway, I wouldn't call this a 'hot' mould.
I can cast at a comfortable pace, and don't feel 'delayed' waiting for the sprue to mature. It seems to spend most of it's time just below 300° and produces a smooth, shiney bullet the Lone Ranger could pass off as a silver one.

It doesn't appear to lose much of it's 'proper' heat while maintenance is going on, and quickly gets up to temperature if it is a bit cool.

I'm happy.

Hope the 'data' helps fill out your spreadsheet...
CM

[montana_charlie]

CM
If you're waiting 3 then 5 seconds to open the sprue plate, I'd call this mold WARM at least. But, don't pay any attention to that.
I must pay attention to how you might describe it, because, for one thing, this is your project. But, any description, if it's going to be useful to a membership with such a wide range of 'style' and 'opinion', needs to be calibrated to some standard that is universal to all of us.

If I don't see the sprue remain liquid for two or three seconds (which I have been) I would increase pot temperature until that did happen. I feel that these large bullets require that much time to assure fillout, air expulsion, whatever.

After freezing, I wait several seconds before cutting the sprue. Cutting at the wrong time causes that little divot (on many moulds) and I always want to avoid that. Giving the sprue 'time to mature' (as I call it) assures the divot doesn't appear.

A caster adjusts his pot temperature to make a given mould condition possible, then adjusts his rhythmn to maintin that condition consistently. If he feels the need to slow down, he might wave his mould in the air, place it by a fan, or just count off a number of seconds. When (within his cycle) he does this depends on his 'style'. Guys who cast many different kinds of bullet, using single and multi-cavity moulds, might have several 'styles'.
Since I always cast big bullets from single cavity moulds, and always use a dipper, my 'style' never changes.
That style allows two adjustable 'waiting periods' which provide the rythmn needed to maintain the mould condition I want.

One is the 'sprue maturing' wait, and the other is the dipper filling period. I can quickly scoop a dipperful, or I can fool around with stirring and surface clearing before letting the dipper fill (kinda) gradually.

One 'pause' occurs with the mould full of hot (but solid) alloy, and the other happens when the mould is empty.
I really don't think about them much (either one) but when things are working right, those two 'periods' stay pretty consistent at whatever thay have become...for that mould, during that session.
If I conciously change one, it will usually be to fill the dipper more quickly...to keep things hotter by going faster.

If I find that makes things a little 'frantic', I will raise pot temp, a bit.

On a scale of HOT WARM IDEAL COOL COLD, about making good bullets fast, where would you rate the mold?
That brings me to trying to give you a rating.
My inclination is to rate the mould based on how easy it is to get it to make good bullets...period.

If it was necessary to keep a torch going to bump up the mould temperature, or use a fan to cool it off, I would have no trouble selecting from your list. The difference between HOT and WARM...or between COOL and COLD would depend on 'how much' I had to use those accessories to get good bullets.

Since I can get good bullets without accessories, and can get them at a pace which makes casting a relaxing pursuit, and, since I find the mould can operate in a 'range of temperature' without either making wrinkles or causing frost, I would rate it as IDEAL.

However, you ask me to rate it according to a parameter I don't use, and don't fully understand.
That parameter is 'making good bullets fast'.
CM

[HORNET]

Hey Joe...
Finally solved a logistics problem and got the information that you requested back about post #56.
Lyman single cav #225415 Mold weight (exc. Sprue Plate) 5.8 oz, Factory steel Plate 0.7 oz, Aluminum Plate 0.3 oz, overhang area 0.5 sq. in. for Alum. plate, 0.27 sq. in. for factory, Boolit weight range 48.4 gr (Lino) - 50.9 gr (WW) ave. 49.6gr as cast - Casts about the same with both plates (see note for RCBS)- Sprue size was originally smaller in the Alum. plate and was opened up until it cast satisfactorily. I use the same size Aluminum plates on all my Lyman singles up to about .32 cal (and on some others :roll:) with the sprue holes opened up as needed.

Lyman 2 cav. #375449 Mold weight (exc. Sprue plate) 8.7 oz, Factory Plate 1.2 oz, no Alum Plate, Boolit weight approx. 275 gr (#2 alloy or thgereabouts), overhang area 0.50 sq. in.- Haven't cast from this mold in a very long time since it was such a pain to use even as a single cav. It was very touchy and took a lot of patience [smilie=b:.

RCBS # 22-055-FN Mold weight (exc. Sprue Plate) 11.8 oz, Factory Steel Sprue plate 1.8 oz, Aluminum Plate 0.6 oz, overhang area 1.09 sq. in. for both (identical shapes), as cast weight 53.0 gr - 55.6 gr ave 54.6 gr - both plates cast about the same but I seem to get better uniformity with the Aluminum plate and I think the smaller sprue mark gives a more uniform surface for the gas checks to seat against. I do notice that the front cavity (which would be more affected by the extra cooling from the overhang) is slightly more difficult to get good fill on. I had planned on opening up the sprue hole on that cavity another 0.005" but may trim the plate back instead (if it ever cools down- record high of 92 degrees 2 days ago :???:).

I cast about like MT Charlie, start with the alloy about 750 degrees, dip the front edge of the blocks in the alloy about 15 seconds to warm things up adfter cleaning then wipe off anything that sticks and smoke the cavities, then run things as fast as I can and adjust as indicated by fast inspection of the boolits between casts. I do find that my best consistancy comes using a dipper. YMMV. Once I hit the right conditions, I usually run about 6-7 pounds of .22's from one mold at a shot. I really need to start a log of conditions.[smilie=1:
That should give you something to think about. If you need more info, just ask. It might take a while......

[joeb33050]

"Ideal" is what I put down.
Thanks;
joe b.



I must pay attention to how you might describe it, because, for one thing, this is your project. But, any description, if it's going to be useful to a membership with such a wide range of 'style' and 'opinion', needs to be calibrated to some standard that is universal to all of us.

If I don't see the sprue remain liquid for two or three seconds (which I have been) I would increase pot temperature until that did happen. I feel that these large bullets require that much time to assure fillout, air expulsion, whatever.

After freezing, I wait several seconds before cutting the sprue. Cutting at the wrong time causes that little divot (on many moulds) and I always want to avoid that. Giving the sprue 'time to mature' (as I call it) assures the divot doesn't appear.

A caster adjusts his pot temperature to make a given mould condition possible, then adjusts his rhythmn to maintin that condition consistently. If he feels the need to slow down, he might wave his mould in the air, place it by a fan, or just count off a number of seconds. When (within his cycle) he does this depends on his 'style'. Guys who cast many different kinds of bullet, using single and multi-cavity moulds, might have several 'styles'.
Since I always cast big bullets from single cavity moulds, and always use a dipper, my 'style' never changes.
That style allows two adjustable 'waiting periods' which provide the rythmn needed to maintain the mould condition I want.

One is the 'sprue maturing' wait, and the other is the dipper filling period. I can quickly scoop a dipperful, or I can fool around with stirring and surface clearing before letting the dipper fill (kinda) gradually.

One 'pause' occurs with the mould full of hot (but solid) alloy, and the other happens when the mould is empty.
I really don't think about them much (either one) but when things are working right, those two 'periods' stay pretty consistent at whatever thay have become...for that mould, during that session.
If I conciously change one, it will usually be to fill the dipper more quickly...to keep things hotter by going faster.

If I find that makes things a little 'frantic', I will raise pot temp, a bit.

That brings me to trying to give you a rating.
My inclination is to rate the mould based on how easy it is to get it to make good bullets...period.

If it was necessary to keep a torch going to bump up the mould temperature, or use a fan to cool it off, I would have no trouble selecting from your list. The difference between HOT and WARM...or between COOL and COLD would depend on 'how much' I had to use those accessories to get good bullets.

Since I can get good bullets without accessories, and can get them at a pace which makes casting a relaxing pursuit, and, since I find the mould can operate in a 'range of temperature' without either making wrinkles or causing frost, I would rate it as IDEAL.

However, you ask me to rate it according to a parameter I don't use, and don't fully understand.
That parameter is 'making good bullets fast'.
CM

[joeb33050]

Hornet;
On the scale "COLD, COOL, IDEAL, WARM, HOT" making good bullets fast how do you rate
225415SC with stock sprue plate
RCBS 22-055 FN DC with stock sprue plate
375449 DC with stock sprue plate

Thanks;
joe b.





Hey Joe...
Finally solved a logistics problem and got the information that you requested back about post #56.
Lyman single cav #225415 Mold weight (exc. Sprue Plate) 5.8 oz, Factory steel Plate 0.7 oz, Aluminum Plate 0.3 oz, overhang area 0.5 sq. in. for Alum. plate, 0.27 sq. in. for factory, Boolit weight range 48.4 gr (Lino) - 50.9 gr (WW) ave. 49.6gr as cast - Casts about the same with both plates (see note for RCBS)- Sprue size was originally smaller in the Alum. plate and was opened up until it cast satisfactorily. I use the same size Aluminum plates on all my Lyman singles up to about .32 cal (and on some others :roll:) with the sprue holes opened up as needed.

Lyman 2 cav. #375449 Mold weight (exc. Sprue plate) 8.7 oz, Factory Plate 1.2 oz, no Alum Plate, Boolit weight approx. 275 gr (#2 alloy or thgereabouts), overhang area 0.50 sq. in.- Haven't cast from this mold in a very long time since it was such a pain to use even as a single cav. It was very touchy and took a lot of patience [smilie=b:.

RCBS # 22-055-FN Mold weight (exc. Sprue Plate) 11.8 oz, Factory Steel Sprue plate 1.8 oz, Aluminum Plate 0.6 oz, overhang area 1.09 sq. in. for both (identical shapes), as cast weight 53.0 gr - 55.6 gr ave 54.6 gr - both plates cast about the same but I seem to get better uniformity with the Aluminum plate and I think the smaller sprue mark gives a more uniform surface for the gas checks to seat against. I do notice that the front cavity (which would be more affected by the extra cooling from the overhang) is slightly more difficult to get good fill on. I had planned on opening up the sprue hole on that cavity another 0.005" but may trim the plate back instead (if it ever cools down- record high of 92 degrees 2 days ago :???:).

I cast about like MT Charlie, start with the alloy about 750 degrees, dip the front edge of the blocks in the alloy about 15 seconds to warm things up adfter cleaning then wipe off anything that sticks and smoke the cavities, then run things as fast as I can and adjust as indicated by fast inspection of the boolits between casts. I do find that my best consistancy comes using a dipper. YMMV. Once I hit the right conditions, I usually run about 6-7 pounds of .22's from one mold at a shot. I really need to start a log of conditions.[smilie=1:
That should give you something to think about. If you need more info, just ask. It might take a while......

[HORNET]

I rate both of the .22's as cool - very useable but you've gotta hustle a little to keep things running well.
The 375499 qualifies as very hot and very rarely gets used.
On the other hand, the RCBS 32-170-FN , 27-150-SP, and 35-200-FN all rate very close to ideal IMHO. The other Lyman doubles that I have tend to rate in the warm range, especially those over about 175 gr.
I do notice that you don't have any geometry factor involved for the design. I find that there's a lot of difference between casting .38 cal 148 gr wadcutters and .264 cal 146 gr Loverins.......

[joeb33050]

I do notice that you don't have any geometry factor involved for the design. I find that there's a lot of difference between casting .38 cal 148 gr wadcutters and .264 cal 146 gr Loverins.......

It appears that if the bullet is shorter/fatter, that the mold is not as HOT. The numbers suggest that 429421DC should be HOT and a bit of a problem. I rate mine a WARM, and it's not a big problem. The ratio of surface area to volume is lowest with a sphere, and short pistol bullets are closer to spherical than your .264 caliber bullets.
I'm not looking for real precision or perfect science here; it appears that the majority of molds are fine.
RCBS is sending me a DC 22 55gr and a DC 446 370 grain mold to try and then to cobble up "fixes" for-these are the molds with the least and most bullet wt. from the RCBS line.
I'll be looking for testers next week.
I wish I could put the EXCEL workbook up here.
Thanks;
joe brennan

[charger 1]

The biggest problem we have in every step of the cast bullet process is the correct diagnosis of a problem. We see it here all the time. One step is taken to correct or compensate for something or the lack of something else. If the variables are fixed, then you must adapt.

I have been given a one cavity LBT mold of a 230 grain olgival wadcutter in 44 caliber. All my past experience with his molds have been two cavities. After trying every trick in the book from opening the sprue hole to improve venting and flow rate, this mold is impossible to cast unless you are at 800 degrees and 850 is better, regardless of mix or smoke in the cavities. And you still need to cast like a madman. You can forget frosting without going up in temp which my RCBS pot won't do. Two bullets in this same block size and material would have allowed normal casting temps and rates.

1. So mold size does matter. 2. Or block material does matter. 3. Or lead volume does matter and thus the temperature of that lead. Or your casting rate if you can't control variables one and two.



There is an opposite side to that to Bass. I just got my 50 from Veral. Its apparent to me that Verals one size fits all sprue plate shoulda been made with the holes just a smidge farther apart to accomodate for 50 cal cavities. I'm not saying a fella cant pour two good boolits from it, but by golly you'd wanta be on yer game. With the wall between being SOOOOO thin the second one poured is almost gauranteed to have a frost on one side. Or if its OK that means you ran the first one so cool that it has rounded corners. Its a two cav that I can run twice as fast as a single as long as I stay to the same hole and keep the temp constant

[joeb33050]

I have been given a one cavity LBT mold of a 230 grain olgival wadcutter in 44 caliber. All my past experience with his molds have been two cavities. After trying every trick in the book from opening the sprue hole to improve venting and flow rate, this mold is impossible to cast unless you are at 800 degrees and 850 is better, regardless of mix or smoke in the cavities. And you still need to cast like a madman. You can forget frosting without going up in temp which my RCBS pot won't do. Two bullets in this same block size and material would have allowed normal casting temps and rates.

1. So mold size does matter. 2. Or block material does matter. 3. Or lead volume does matter and thus the temperature of that lead. Or your casting rate if you can't control variables one and two.

I can't deal with aluminum molds now, trying to understand the iron molds.
I've been busy with the book, we're selling copies on CD and in print now. But I'll be back.
The problem with this mold is that it gets rid of the heat too fast, it is a COLD mold. There seems to be a relationship between mold size and weight and bullet weight. If the bullet weight is too small for the blocks, the mold is COLD. If the bullet weight is too large for the blocks, the mold is HOT. Pistol bullets don't seem to cause HOT molds as much as do rifle bullets.
Now, here's how to fix the mold.
First, if the sprue plate is big, make a smaller one. If that doesn't work, start taking material off the mold. This takes, for me, an hour or so to figure out where to take the material off. You want to reduce mold WEIGHT and SURFACE AREA. Another alternative suggested is to paint the outside of the mold with barbecue paint, I have no opinion on this. Yet another alternative is to drill a hole or holes into or through the mold. Look it over, you'll see where holes can be drilled.
Keep us informed.
joe brennan
So, chop that sucker up

[leftiye]

I know you'll LOVE this.... Ever think that we can regulate the ambient temperature that the mold cools off in? I can think of several ways to make a mold that can't be easliy heated up from cooling down. The latest would be to find a way to actually keep the area/space that the casting takes place in hotter or (cooler). As we most of us wear gloves, and long sleeves while casting, this could be as easy as having our casting setup inside a hood.

[joeb33050]

I asked RCBS for samples of what I figured were their hottest and coldest molds, and they sent them to me, free. The plan is to have experienced casters use the molds, rate them hot or cold. Then return the molds to me, I'll find someone to modify the molds in some fashion to make them more IDEAL, back to the caster for another evaluation.
The DC22 055 FN was sent to a caster on the CBA page.
I have a new DC .446" 370 grain mold, for 11 MM Mauser etc., (It's marked incorrectly).
I'd like this mold to go to someone who can use the bullets he casts. And who will do the evaluation.
So, if you want to help out, send me your address and I'll send the mold.
Thanks;
joe brennan

[Bass Ackward]

There is an opposite side to that to Bass. I just got my 50 from Veral. Its apparent to me that Verals one size fits all sprue plate shoulda been made with the holes just a smidge farther apart to accomodate for 50 cal cavities. I'm not saying a fella cant pour two good boolits from it, but by golly you'd wanta be on yer game. With the wall between being SOOOOO thin the second one poured is almost gauranteed to have a frost on one side. Or if its OK that means you ran the first one so cool that it has rounded corners. Its a two cav that I can run twice as fast as a single as long as I stay to the same hole and keep the temp constant


Charger1,

Think about it. There are two factors that cause heat to a mold. The lead, and then hot air. Lead pouring down the inside wall is going to force more of the venting of hot air to the far side and top of the blocks away from the center. It is the venting of hot air in small spaces that causes the super heating. So he is trying to take the extra heat AWAY from the center of the blocks where it is going to affect the other cavity and channeling it to where the aluminum can convect it away.

You'll learn how to use that mold. Besides, there is no law that says you have to fill both. Personally, I'd pour one and alternate cavities. Probably will turn out to be faster and better quality.

[joeb33050]

On 11/20/07 I set the Lee 20# pot going with linotype and the 31141 DC mold balanced on the rim. Reduced the temperature, ended with the thermostat set at a bit over "7". Started casting at 2PM, fiddled a bit, stopped at 4PM. It was necessary to wait for the sprue to harden, else there were torn holes in bullet bases. I inspected two bullets in that sprue hardening time. In the 2 hours I cast 245 good bullets. Starting alloy temperature was 630 degrees, ending was 690 degrees. Don't know why the change, I thought the temp had stabilized when I started casting. Standard deviations were .085 and .124 grains, so the bullet weights remained stable.
joe b.

[joeb33050]

The time taken to cast good bullets is reduced when the alloy temperature is reduced.
I'm starting to believe that the first step in a casting session should be to find the lowest thermostat setting and temperature where good bullets can be cast.
I'm also starting to believe that recording the thermostat setting, alloy temperature at the beginning and end of the session and a description of the alloy and the bullet weights is important in allowing fast casting.
On 11/25/07 I cast 31141 at as low a heat as I could. Starting temperature at 1:45 PM was 660 degrees, ending temperature at 3:30 PM was 720 degrees, with the Lee 20# pot set at a shy "7".
I'm left handed, so there's a lot of hand-changing and fumbling going on. There was a wait of only a few seconds for the sprue to become dull, signalling that the alloy had hardened. If I opened the sprue plate too soon, the bullet bases showed holes-a sure signal. On 11/20/07 the sprue took a long time to harden, enough time to inspect two bullets before opening the sprue plate.
The bullets cast on 11/20/07 of "linotype" are too hard to go through the Lyman 450 lubrisizer, so lead was added to the "lino".
(Cavities are marked with dots, one up top and the other down at the bottom of the nose.)
There were 172 good Top Dot bullets, average weight was 166.1 grains, standard deviation was .168 grains.
There were 174 good Top Dot bullets, average weight was 166.8 grains, standard deviation was .159 grains.
(These standard deviations are high, however the outliers are used as foulers. Thus of the Top Dot bullets, only the center-weight 155 bullets, with average weight of 166.2 grains and standard deviation of .111 grains will be used "seriously".)
These bullets are ~4 grains heavier than those cast 11/20/07.
On 11/20/07 it took 2 hours to cast 245 good bullets, a rate of 123 bullets per hour.
On 11/25/07 it took 1 3/4 hour to cast 346 good bullets, a rate of 198 bullets per hour.
As I suspected, casting speed is determined by the temperature of the alloy as well as the dimensions and weight of the mold and bullets cast.

joe b.