Uneven mould temp w/big boolits

[geargnasher]

Ok, I call on the wisdom of the more experienced again!

I've been dinking with my new Lyman 452664 two-banger trying to get the drive bands the right size (they cast .450 with air quenched ww when new, I've lapped it to .454") and I keep noticing that the middle and rear drive band areas in the mould start overheating just after the nose area fills out good. Shortly thereafter the sprue starts to smear, so experience proved a 20-second wait between pours was required for the upper half of the mould to cool off.

I never have this problem with smaller boolits in the same blocks because (it seems) that there is more iron surrounding the cavs. The 452664 has paper-thin walls around the sides of the boolits and almost the entire lower half of the blocks are solid. It takes a while to get the noses to fill out, then the drive bands start to round badly from overheating. I've done about a dozen casting sessions with this mould with a known good alloy and I haven't figured out it's sweet spot yet because it is so high in mass on one end an low on the other compared to other 2 cavity moulds.

Any techniques I should try to even the temp and keep a decent production speed?

I experimented with quenching the sprue plate on a wet sponge like I do with my Lee moulds, and the best I could do was get the base to fill out well. If I cooled it any more so the middle filled correctly the base was TOO cool and again I had fillout problems there. :roll:


Gear

[chevyiron420]

i think ifyou get some of the sprue plate lube, it will help with the smearing. i didnt have any of the regular stuff so i used a little dab of antisieze on the bottom of the sprue plate and then polished it with a rag untill it seemed gone. after that i didnt have any smearing anymore as long as i let the sprue harden up good. then i raised up my alloy temp some, and set up a ten or twelve inch fan about 10 feet away blowing accross my area. after that i could count to ten after the sprue frosted and cut it, drop the boolit, hold the mold up in the air path of the fan for a ten or so count, and pour another. your results may be different but thats what my mold wanted!:cbpour:

[MtGun44]

I you use Bullshop Plate Lube (see link at bottom of page or sponsor page) you will
never get smearing again and can run hotter.

I have no connection to them except as a very satisfied customer. The slightest hint
wiped on the bottom surface of the sprue plate with a Q -tip will totally eliminate this problem,
and if you have some smearing, it will gradually go away as you cast if you use Bullshop
Plate Lube.

Bill

[geargnasher]

I use a fan to that effect, and have 20 second cooldown intervals. I usually have 5 second-after-sprue-freeze intervals with my other steel moulds because they heat evenly and I can keep a good balance between alloy temp, mould temp, and casting rhythm and cast all day at a decent speed (about 5 pours per minute), but with this mould I can only get 2 pours max per minute and still have to constantly monkey with the routine. Even then I cull about 50% of these due to the middle band either being too hot (rough, rounded, and undersized) or too cold (shiney and wrinkled).

Maybe I just need to use Kroil [smilie=b:

Gear

[geargnasher]

I you use Bullshop Plate Lube (see link at bottom of page or sponsor page) you will
never get smearing again and can run hotter.

I have no connection to them except as a very satisfied customer. The slightest hint
wiped on the bottom surface of the sprue plate with a Q -tip will totally eliminate this problem,
and if you have some smearing, it will gradually go away as you cast if you use Bullshop
Plate Lube.

Bill
Thanks for the tip, Bullplate is on my "to get" list. Problem is the band areas overheat before the sprue starts to smear, seems I can't get good noses, good bands and bases all on the same boolit because the mould temp won't even-out across the cavities with the techniques I have tried.

I'm theorizing that this is due to the difference in mass (and heat-holding ability) of this mould with 2 big 250-grain cavities in only the top half of the blocks, but my 454190 casts with good fillout all day, no problem, as do a half-dozen other Lyman 2 cavity blocks of smaller calibers. Maybe the more tapered nose of the 454190 lets heat sink more evenly through the blocks than the huge meplat of the 452664, but I dunno.

Gear

[leadman]

I have been having problems with a lyman 4 cavity for the 200gr SWC. Not sure if it would help to use the alloy the moulds were designed for, Lyman #2. 90% lead, 5% tin, 5% antimony. Fairly expensive alloy, but should flow well.
I think I will add tin to my alloy and see if it helps.

[44man]

The problem is described right and it is because Lyman never makes larger blocks for larger boolits. Even a Lyman 12 ga mold is the same size as one for a .22 boolit. Heat distribution sucks.
This can cause out of round , large boolits too.

[runfiverun]

i use the 452664 mold and once the mold is hot i turn the heat down on the pot to about 675* and run a tad of tin.
i also turn the mold over so the sprue is down as soon as it flashes over to distribute heat more evenly.
try using a 22 cal rcbs mold you have to constantly heat the mold as you go.

[mooman76]

I was going to say what runfiverun said. Turn the hat down a little. Larger cavity moulds have more lead to heat them so need less heat than a small cavity. That and the bull plate lube should get you movin faster.

[MtGun44]

More tin.

Scrub with Comet and toothbrush.

Bill

[geargnasher]

i use the 452664 mold and once the mold is hot i turn the heat down on the pot to about 675* and run a tad of tin.
i also turn the mold over so the sprue is down as soon as it flashes over to distribute heat more evenly.
try using a 22 cal rcbs mold you have to constantly heat the mold as you go.

I tried as little heat as possible, thinking that the mould blocks had to disperse a lot more with the bigger boolits, and even cast until the noses were shiny again but then the bases wouldn't fill. I'm beginning to think I need to try another brand of mould with more mass to even the heat, or perhaps figure a way to whack about 1/3 of the bottom off this one so the cavities can heat evenly and STAY that way for more than 1 or 2 pours.

Any suggestions for a good .45 Colt boolit mould for general use on steel and game in pistol and rifle???

Thanks,

Gear

[Whitespider]

Ok, I call on the wisdom of the more experienced again!

Well I don’t know where my experience level is when compared to yours, but... here’s my two-cents worth.

First, I never change the temperature of my alloy; I always run it as hot as my heat source allows (an old electric kitchen range). It doesn’t matter if I’m pourin’ .22 or .45 caliber, single or double cavity, aluminum or steel molds. I don’t know what the melt temperature is because I don’t have a thermometer; I don’t care what the melt temperature is because I always run it the same... full hot. I’ve tried playing with the heat setting and found that I have much better results running full hot and varying my technique as the mold dictates.

Second, I pour with a ladle, I don’t own a bottom pour pot and when I read about the reject percentage that many guys get with bottom pour pots, well... I believe I’ll stick with the ladle. I cast over 350 Lyman 454190’s this past weekend and had exactly 2 (yes, that’s only about ½%) rejects.

Third, straight WW metal sucks for pouring boolits, I don’t care what anyone says. I learned real quick, straight WW metal needs too much heat in the mold for good fill-out and there’s a real fine line between good fill-out and an over-heated mold (resulting in poor driving band fill-out). The addition of about 2% tin improves the cast-ability more than enough to justify the small cost.

Fourth, I use a small $10.oo fan mounted to the wall and blowing straight down to control the temperature of the mold. I start by setting my mold on another one of the burners (set on medium/medium-high) as the pot comes up to temperature, this way I start with a fully pre-heated mold. I make the first pour and swing the mold under the fan (sprue up) for a couple seconds, cut the sprue and dump the first pour in the sprue/reject pile, if all looks well (almost always does) I drop the second pour on the towel. I don’t like frosted boolits, but use frosting to indicate when the mold is getting a bit too warm. So... I pour, swing the mold under the fan (anywhere from 2 to 8 seconds, depending), cut the sprue, drop the boolits, repeat. If at any time I notice some frosting beginning on the boolit (nose, side, base, driving band) I close the mold and sprue plate, and hold the side or area of the mold that was beginning to frost under the fan for about 2 to 3 seconds before making the next pour. When I need to add metal to the pot, or flux, I fill the mold, cut the sprue and set it on the pre-heat burner, when the pot comes back up to temperature I drop the boolits still in the mold and get right back at it.

Learning to precisely control the temperature of the mold (or area of the mold), and the addition of a bit of tin to WW metal, has given me the best results.

http://i624.photobucket.com/albums/tt321/Whitespider8591/DSCF0003.jpg

http://i624.photobucket.com/albums/tt321/Whitespider8591/DSCF0001.jpg

[geargnasher]

Whitespider, thanks for the tips, those boolits sure are purty.

I do use a fan, blowing from across my left shoulder (I hold the mould with my left hand) toward the general pot area, but not where I can put the mould under it directly.

The alloy I've been using is WW + 4% 50/50 bar solder, my standby stockpile mix that I use for everything except hollow points. It water drops to 18 bhn if I need it that hard for .357mag or some rifle applications. It air quenches at 13.5 bhn in 3-4 weeks and works like magic in all my moulds including Lees except for this one, which is the only one that has fillout problems. I have a Lee 20lb bottom pour that isn't the best at keeping temps stable, but I can keep it where it needs to be to work well. I have a setting I use that works for everything as long as the pot is between 1/3 and 3/4 full, so I stop and add, mix, flux, skim, and continue every 8 pounds or so.

This mould just stumps me. I tried again tonight with 20:1 and a freshly scrubbed mould, but it just seems to overheat the drive band area unless I can figure out how to effectively cool the top half of this thing.

Just had a thought, I think I'll try setting the poured mould on a thick piece of copper under a fan and casting with another mould while it cools. What a PAIN.:groner:

Gear

[geargnasher]

Oh, Btw Whitespider, I have a tip for your 454190 to help that mould seam: Polish the cavities for about a minute each with a boolit, electric drill, and cut-off 3" screw stuck in a 1/8" hole drilled in the base. I have lapped a lot of Lymans and found that 380-440 grit clover compound works best and you get virtually NO visible or measurable seam after doing it.

FWIW

Gear.

[Marlin Hunter]

http://i624.photobucket.com/albums/tt321/Whitespider8591/DSCF0003.jpg




I am totally jealous of your bullets. :lovebooli

[JCherry]

Geargnasher,

You might try smoking your mould with a BIC lighter. I have a similar problem with a single cavity 446187 470 grain mould and that seems to work for me. I'm using straight WW at 800 degrees, ladle poured.

Have Fun,

JCherry

[runfiverun]

just fix the base smear with a damp rag ,touch the sprue to it ,to help draw the heat out from just that part of the mold.
this will harden the base of the boolit enough to cut it and retain heat in the base.

[geargnasher]

just fix the base smear with a damp rag ,touch the sprue to it ,to help draw the heat out from just that part of the mold.
this will harden the base of the boolit enough to cut it and retain heat in the base.

Maybe I don't have my "English" right on the damp sponge technique, but as I've said in my original post I tried that, too, works great for evening the temp in the Lee moulds (the alum. loses heat so much faster than the steel sprue plate does) but just when I get the middle band cooled down enough to fill out and quit being dull and undersized, the sprue plate is too cold.

I will try again, there has to be a happy medium with this stubborn mould somewhere.

Thanks for the input, RFR.

Gear

[runfiverun]

it is [i think] my typing english, the computer service has been acting up all day.
if it is the middle of the mold i would look at the venting in that area and maybe go with my earlier suggestion of lower heat and tin.

[geargnasher]

No, no I wasn't being sarcastic, RFR, what I meant by my "english" wasn't that you didn't get my meaning, I was referring to "english" as technique, like a tricky curving billiard shot! Sorry to come off insultingly. I need to experiment more with sponge quenching and air cooling with a fan like has been suggested, maybe I can control the temp better that way.

Gear

[beagle]

Try casting one cavity at a time....alternating cavities between casts. If this produces good, filled out bullets, you don't have a vent problem but a cooling problem.

I'm suspecting a cooling problem as I experience this when casting with high volume cavities in Lyman blocks such as the 429421 and also with very large cavity .45s in small Lyman blocks.

The problem is that there is not enough mould block material to dissipate the heat. I seldom encounter this problem in RCBS moulds or Saeco moulds as they use generous sized blocks.

When Walt Melander was alive and running NEI, you could tell him what bullets you wanted in what material and he had worked up a computer program to tell him if it would work or not. I once ordered a DC .375 mould from him with bullets running over 300 grains and he did his magic and said it won't work. I persisted as I was wanting two different style .375s in meehanite blocks and figigured that worse case, I could cast one at a time or alternate cavities. Sure enough when it arrived and I cast with it, I had problems unless I alternated cavities.

Too bad that computer program is not available and adherred to by Lyman. But, they do have good designs and are worth messing with.

The only other alternative I can suggest has been suggested above. Slow down your casting tempo and use a "cool box" with a high volume fan underneath blowing upwards or use two different moulds./beagle

[geargnasher]

Thanks, Beagle, I hadn't thoght of alternating cavities. I bet that fixes it.

Gear

[runfiverun]

you wasn't being nothing, i re-read what i typed and it made poor sense to me too.
i must have just misunderstood what you had typed or didn't read it carefully enough.
not your fault at all.