Newbieee has 3 "Q's"

[DrBill33]

Beem reloading for over 58 years, now have begun casting ... and it is fun! I do have some "Q's":

1: What temp range is best for casting? i have been using ca. 700-750. Is this the proper range?

2: At times, the base has not a dimple, but an actual small hollow. What have I done wrong? It does not happen often, but it does happen, and the bulklet is recast

3: I am using a very close approximation of Lyman #2 (actual BHN = 14.769, instead oif #2 BHN of 15). In (say) a 240gr mold,how much lighter will the alloy mix be? My 240 are coming out at 216+/-1.5 What I am seeking, is some mathematical formulae to calculate th actual weight when using #2 in lieu of the Pure Lead figure of 240, etc.,

Thanks! And Keep your powder dry!


DrBill

[Leftoverdj]

DrBill:

1. Hotter than you are casting and your alloy will emit lead fumes. That's very bad for the caster.

2. Timing in cutting the sprue. A tiny bit longer before cutting will cure that, but exact timing can be tricky.

3. This ain't an exact science, but if you are getting 216 grain bullets out of a 240 grain mould, either your alloy is nowhere near Lyman #2 or your mould is nowhere near 240 grains. I'd guess that your alloy is some form of solder and is about half tin.

Mould are not as exact as we would like to think. The makers are likely to calibrate them with anything and I suspect that they sometimes just guess. Most of us are working with mystery metals anyway so a few grains one way or another is normal. 10% off nominal weight is not normal.

[theperfessor]

1. Proper temperature is whatever it takes to get good fill-out of bullet. Lee aluminum molds usually need to be run hotter than ferrous molds. The idea is to reach a stable temperature. This depends on mold, alloy, and your casting speed. Some people don't like the frosted bullet that come from casting hot, but its cosmetic only - frosty, well-filled out bullets work fine.

2. Leave a big puddle on top of sprue plate. This provides material to be pulled down into cavity as bullet cools, and helps keep mold hot.

3. Somebody will probably post links to various lead alloy calculator programs. They can be real useful, but don't try to cut things too fine. Unless you are working with certified materials, the scrap (WWs, etc.) used by most casters varies enough to make exact BHN/density/weight predictions difficult. And mold cavities vary in size also. They are a guide, not a guarantee. Throw away anything to the right of the decimal point for BHN, and give yourself a little more tolerance. A 15 BHN bullet isn't different enough from a 14 or 16 BHN bullet to worry about. Just make a big enough melt so that you have enough ingots made from one batch of alloy to make each bullet in a production run consistent.

[DrBill33]

Thanks. The alloy is tested at the BHN stated, and the Sn and Sb are equal in amounts (4.92% each), whereas #2 is 5% each. Materials are neither scrap nor utilized without BHN testing. I will try to wait a little longer before I release the bulltes. I actually a cast 2 different bullets at the same time. A .44 or .45 on my left and a .380 or 9 mm on my right. It seems better than sittting and waiting SO-O-O-O long for the initial cooling!

[montana_charlie]

It seems better than sittting and waiting SO-O-O-O long for the initial cooling!
How long is "SO-O-O-O long"?
If the sprue puddle stays liquid for five seconds, that should be long enough for all of the air to escape, and the cavity to fill well.

If five seconds seems TO-O-O-O long for you, you're in a much bigger hurry that I am.
CM

[MtGun44]

Don't worry about "lead fumes". You have to get far hotter that a casting pot will get
to have any appreciable vapor pressure with lead alloys. Run the pot at whatever temp it
takes to get the boolits to fill out properly. Frosty is just fine, too.


Democracy is a bad idea. That is why we have a Republic.

Bill

[runfiverun]

that small hollow is from there not being enough lead there,[on the sprue plate] to suck into the mold when the boolit cools
you just need to know how much less tin and antimony weigh than lead figure your percentages and that will give you a total..
slow up some and that 5-5 will pour fine at 750,unless you are using aluminum molds .

[Doble Troble]

Fill each cavity until lead pools on the sprue plate.

[mdi]

Check page 58 of your Lyman Cast Bullet Handbook for a chart of the "Predicted As-Cast Charistics". May not be as accurate as you like (4.92% vs 5.0%) but I'm sure it'll be helpful.
For my own info., how much differenc does .08% tin and antimony make in bullet alloy?

[ScottJ]

How long is "SO-O-O-O long"?
If the sprue puddle stays liquid for five seconds, that should be long enough for all of the air to escape, and the cavity to fill well.

Thanks for this. I'm new to this addiction too and was just about to ask how long this should be taking.

My first attempt was last Sunday and I was ladle casting into a Lee mold.

My process was to hold the mold over the pot, ladle into one chamber, go back to the pot for more (first sprue would solidify while I did that), then ladle the other chamber.

By the time I put the ladle down and grabbed my whack it stick the second sprue would be solid.

[Wayne Smith]

When anything (except water) cools from it's liquid state to it's solid state it contracts. The hole you are experiencing is most likely from this contraction. The solution is to have a sprue large enough and a sprueplate/mold hot enough that the sprue stays molten and is available as the boolit cools. This fills in the hole.

Don't worry about the heat, I have had my pot up over 900 degrees (unnecessary, I wasn't paying attention) and typically cast some of my molds at 800. Find out what your particular mold likes with that alloy and have fun.

When I have a mold running good I typically pour and the sprue will harden (you will see it suck down and change reflectivity) usually in a count of six, or six seconds. If it takes much longer than that your mold is probably a little hot. Some people use a fan, others a wet sponge, but cooling the mold periodically is necessary for some molds. If your mold is that hot you are probably getting frosty boolits - nothing wrong with that but it does slow down the process.

[EDK]

ScottJ Are you using a LEE ladle? Get a bigger ladle or a LYMAN/RCBS dipper. Filling one cavity at a time is awful slow...but I like four and six cavity moulds. Mass production of GOOD boolits is the name of the game.

I use an aged HENSLEY & GIBBS ladle from the late 70s and it holds enough to fill a six cavity mould.

It's beyond me why most mould makers don't cut a trough from sprue hole to sprue hole like the HENSLEY & GIBBS...you get more speed and more metal to fill out also. I did a pretty crude job with a die grinder on most of my moulds...need to take them to work and pretty them up with an end mill. You wouldn't believe how the trough speeds things up with no loss of boolit quality.

+1 on Wayne Smith's comments too.

:Fire::cbpour::redneck:

[Bret4207]

Welcome Dr. Bill. When casting you have two temps to keep in mind- the pot temp of the alloy, which might be anywhere from 675F to 825f +/-, and mould temp. Mould temp is what determines the fill out quality. You vary the mould temp by your casting tempo. The faster you fill and empty the moulds, IOW the more often the mould is being filled, the hotter the mould will run. What you need to find is the happy balance point where you are turning out as close to perfect boolits as possible at a rate acceptable to you. Some people cast at what to me is a snails pace, others tend to cast much faster. I fall into the latter category and like to run my moulds hot enough to get a light frost. With a light frost I get complete fill out without adding expensive Sn or Sb to my WW alloy. Of course a clean mould and alloy are needed too, but I wanted to get the mould temp/pot temp difference across to you.

I would strongly suggest casting with one mould at a time until you get things figured out to your satisfaction.

Here's a link to The BruceB Speed Casting Method- it works! http://castboolits.gunloads.com/showthread.php?t=57105

[ScottJ]

ScottJ Are you using a LEE ladle?

Yeah, Lee. I got it because it was cheap to see if the addiction stuck.

Now I'll just go ahead and get a bottom pour pot.

[Wayne Smith]

If you are pouring big boolits don't bother with the bottom pour, get a Lyman or RCBS ladle. If you are pouring, and will only pour boolits of under about 250gr, get the bottom pour. BTW, the 250 is WAG, I have no idea what the actual size that fails on a bottom pour is.

[EDK]

I've had a SAECO dipper 20 pounder, a LYMAN bottom pour 20 pounder and now a LEE 20 pound dipper (MAGNUM MELTER.) I get better boolits with the ladle/dipper...heavyweights for my 50/90 SHARPS don't come out worth a d*** with a bottom pour! My next pot may be a bottom pour, but I wouldn't bet money on it!

Before I switched to a bottom pour pot, I'd get a bigger ladle. A big ladle and a troughed sprue plate are mass production....and good boolits to boot! Ballisti-cast, sucessor to HENSLEY & GIBBS, has a nice one. The ROWELLS are a little bigger than I like, but they are worth looking at.

I cast mostly 44s, then some 357s, and a few 45/70, 50/90 and 30/30 boolits.

:Fire::cbpour::redneck:

[JIMinPHX]

I usually cast between 650-720, depending on the individual mold & alloy. Some guys cast a little hotter. If your boolits have a frosty finish on then, then you don't want the temperature to go up very much past where you are. That's a good indication that you are at the high end already.

If that dimple in the boolit base looks kind of rough & jagged, that might be because you are tearing the sprue off there instead of cutting it. You can try to wait a little longer before you cut the sprue or you can try to sharpen the sprue plate by rubbing it against a piece of sand paper on a flat surface like a piece of glass. It's more likely that you just need to wait longer to cut the sprue, especially if you are running a little on the hot side to begin with. Pressing the ladle up against the sprue hole & keeping it there for a few more seconds sometimes helps too.

[melchior]

[QUOTE=MtGun44;642752]Don't worry about "lead fumes". You have to get far hotter that a casting pot will get
to have any appreciable vapor pressure with lead alloys. Run the pot at whatever temp it
takes to get the boolits to fill out properly. Frosty is just fine, too.


Do you have any firm info on that?
When I was working in the electronics industry the safety people were pretty adamant about keeping our solder pots below 800. They said that 800 was the temp that lead started to vaporize.

[Edubya]

"Do you have any firm info on that?"
"any appreciable vapor pressure with lead alloys." 859 degree Celsius = 1578.2 degree Fahrenheit
http://www.engineeringtoolbox.com/melting-boiling-temperatures-d_392.html
EW

[Bret4207]

melchior- Edubyas explanation makes sense. You were told 800, but they meant Celsius.

[44man]

A lot of good info. I like the Lyman ladle best but I do NOT depend on the sprue to fill any boolit. I hold the ladle tight to the mold until the boolit takes all the lead it needs FROM THE LADLE before I tip it off, leaving a good size sprue. The larger the boolit, the more time I allow for a good fill. The center of my sprues will just settle as they harden, no divots allowed!
Let it harden enough before cutting.
If you watch in the ladle very closely, you will see it go down as the mold fills, stop for a short time, then the level will drop a little again. That is the time to tip it off, not before.
To just pour fast and leave a big sprue is what causes all of those voids in a boolit.
Another reason I don't like bottom pour. The mold has to be much hotter so the sprue does not set too fast. The line between frosted so bad that boolits drop small or bands do not fill, and boolits that are wrinkled or have internal voids is just too small for most pots to maintain. Thermostat shut off to turn on is too large a range. One drop of slag in the spout changes flow enough to ruin a whole batch of boolits too. Constant cleaning, fluxing and poking wires in the spout turns me off. I would rather make 100 perfect boolits then a fast pile that has to be sorted and weighed.
I don't think I have thrown more then two boolits back in the pot in years and that was trying to get two molds to heat on the hot plate. One will get hotter then the other but a quick play of the propane torch fixes it.