As soon as mold gets up to temp, this happens... Why?

[alping45]

Been a while since I've done any casting, I'm using a Lyman 44 245 SWC mold with 16/1 lead/tin alloy. As soon as the mold gets up to temp to where it starts to fill out, it seems the top drive band is sticking in the mold and gets fractured when the mold is opened. I've tried cleaning/degreasing, smoking, the smoking works for a handfull of drops then the problem returns. What can I do?
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[dkf]

Wait longer before opening the mold and/or slightly reduce the melt temp. See if any of that helps.

[Dusty Bannister]

Let the castings harden just a few seconds longer. You are cutting at the right time, probably, no bases shown, but you need to pause a little longer so the bullet gets a little harder before you pop the handles open. Make sure that the blocks are secure on the correct handles so they are not flopping around too loose. Good luck, Dusty

[Bzcraig]

Wait longer before opening the mold and/or slightly reduce the melt temp. See if any of that helps.

both of these

[OnHoPr]

Are you using a gloved hand or a sprue mallet? If using a gloved hand be careful about twisting the mold or uneven pressure. If using the sprue mallet make sure your whacking at a right angle. I wonder what those would look like if they went through both shoulders and ended up under the hide on the opposite side.

[fryboy]

yup either slow down your cadence ( eg; let the boolt harden a bit longer ) and/or a wee less temp

nice knot btw on that t/c forearm ( i loves purty wood ! ) ( well ..what looks like a t/c forearm lolz looks can be deceiving sometimes )

[Tatume]

Lubricate your alignment pins. If they are sticking they will cause the mold to twist when it is opened. This can and will cause the problem you describe.

[alping45]

Ok thanks for all the advice, I will give it another go tonight. Now I suspect the mold is not opening straight, I remember seeing a slight angled flat on one side of the meplat. What can I use to lube the alignment pins?

[fryboy]

same as you would use to lube the sprue plate eg;bullplate,a very light oil, two cycle oil ,even bullet lube , please note that whatever you use to use it sparingly

[alping45]

yup either slow down your cadence ( eg; let the boolt harden a bit longer ) and/or a wee less temp

nice knot btw on that t/c forearm ( i loves purty wood ! ) ( well ..what looks like a t/c forearm lolz looks can be deceiving sometimes )

Good eye! This is from my G2 carbine, which unfortunately is vacant of a barrel at the moment...

[jcren]

I had that same problem with a 38-105 swc and it was popping the mold too soon. I now cut the sprue and wait 3-4 seconds for the pour to solidify/shrink before opening the mold.

[gwpercle]

You can lubricate with Liquid Wrench Dry Lube also, it won't contaminate the cavity or cause wrinkles. I have started treating my cavities with it because the release so well with it. I would always use too much oil or two-stroke oil and contaminate the cavities causing wrinkles, then I tried the L. W. Dry Lube...no more wrinkles. Put on top and bottom of sprue plate too, it works.
With those big boolits and iron mould I count to 6 or 7 after the sprue frosts over,( solidifies).

[GhostHawk]

I'm with gwpercle, the liquid wrench dry lube works wonders. At the rate I'm using it, should last a lifetime. I use a q-tip and treat brand new molds. Just rub it everywhere, cavity's, pins, sprue, the whole mold. By the time it is warm it is all evaporated. Bullets fly out, even problem children. If they start sticking let the mold cool a bit. Then when it is cool I'll do the cavity's again.

[44man]

Cutting too soon will spin a boolit in the mold too. The glove thing while soft is not the answer.
I use a hardwood stick with a large end that I cut special. Small taps with a downward angle to keep the plate on the mold top. Never a huge smack, just little taps to cut. You should see a bunch of little circles on the sprue cuts. Cutting early will make the sprue break and leave a divot but it does not hurt a thing.
I refuse to cut molten metal.

[Mal Paso]

Lapping the mold will help. 600 grit

Running 2 Iron Molds works too. I cranked out a Lot of 429421 boolits out of 2 Lyman 4 cavity molds. Had the same problem, Iron holds heat better than any other (mold) material.

I eventually lapped one of the Lyman's to cast .432 on all bands and that one casts just fine by itself now. I got a beautiful BC 1103 4C that tears the drive band too. I'll try running it with the Lyman just for kicks. I left one of the Lyman's stock to prove the front band casts almost .427" and the back .429 and a smidge.

With Brass and Aluminum I'm not fast enough to run 2 molds.

[gwpercle]

I'm with gwpercle, the liquid wrench dry lube works wonders. At the rate I'm using it, should last a lifetime. I use a q-tip and treat brand new molds. Just rub it everywhere, cavity's, pins, sprue, the whole mold. By the time it is warm it is all evaporated. Bullets fly out, even problem children. If they start sticking let the mold cool a bit. Then when it is cool I'll do the cavity's again.
My method and results exactly. Q-tip apply but I did find a can of spray in the garage and will give that a try also. Good stuff on moulds.

[Frank V]

I've used parifin to lube the hinge pin & sprue plate.
Don't use too much, it'll bleed into your mould & it'll take a number of castings to burn it out.

[alping45]

OK so here are my findings: first I lubed the alignment pins and sprue plate with high temp anti-seize. I tried waiting longer to open the mold, but unless I waited about 20 seconds it didn't do much good, still breaking the top bands. And after 20 seconds the mold was very hard to open and wouldn't stay hot enough to fill out on proceeding pours. So I finally looked closely at the mold when opening it, the bottom was clearly opening first, which was wedging the top bands in between the halves of the mold and breaking them. I don't really know how I would remedy this, as it was not the pins sticking, I think it was just the geometry of the mold having more to grab on up top than at the bottom. No matter how I tried twisting or manipulating the handles, I could not get any different results. So, I finally came up with a routine to remedy my problem, which actually turned out to be faster than what I was doing before. I would hold the mold in my left hand and fill from bottom pour pot, chop the sprue once solid with a mallet in my right hand, then apply slight outward finger pressure on the mold handles with my left hand, then give the top of the bolt holding the sprue plate on a very gentle tap to the left, the mold would spring completely open in one fluid motion and 90% of the time the boolits would fall free without having to tap the hinge. My old routine was to fill the mold, chop the sprue with the mallet, set down the mallet and use two hands to open the mold, then pick the mallet back up to tap the hinge. After getting the routine down, I was cranking boolits out faster than ever before, I could go as fast as I could, and I didn't see one broken band. I was on such I role, I refilled the pot and cranked out another 10lbs from my RCBS 44-240-SWC mold in 45 minutes. I never had any problems with this mold before, but I used the same routine and it worked fantastic, making the boolits drop free almost every time without needing to tap the hinge. I am not using any sort of lubricant or smoking on the mold cavities.

So in conclusion, next time you have a mold sticking or are getting broken bands, make sure to observe how the mold is opening before jumping to other conclusions.

Here are some pics!

Here's all the rejects from the first attempt going back into the pot:cry:
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The Lyman 44 245 SWC
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The RCBS 240 SWC GC
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And here are the gems that get to digest all these tasty boolits!!:bigsmyl2:
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.44 Mags up top, .44SPL's down low
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[country gent]

Seeral things to try also are 1) after cutting the sprue and bullet is hard enough a few light taps on the hinge pin of the mould handles while opening with one hand. This will usually allow the mould to pop open nd th bullet to rop easily. 2) lube alighnment pins sprue plate hingepins in blocks / handles and handles hinge pin. 3) when closing set blocks on a straight edge ( peiece of angle iron Vee down orks great) this helps to pre alighn pins and blocks. One check is to take a q tip and run over edges of the driving bands corners and edges, if cotton fibers are pulled out there are probably fine burrs on edge and will make mould sticky.

[44man]

Yes, when I open my molds I apply opening pressure and give the handle pin a small whack. Boolits spring free and drop.
I make my molds from thick aircraft aluminum and have run 3 at a time. 2 cavity molds. But I have no trouble with Lee molds either. Cast the first, let the sprue freeze, set the mold on hardwood and cast the second.

[Frank V]

Glad you got it sorted out.
I'm probably not the only one who'd like a range report when you get to shooting those nice bullets?

[fryboy]

So in conclusion, next time you have a mold sticking or are getting broken bands, make sure to observe how the mold is opening before jumping to other conclusions.


no fair you didnt show us how it was opening ! ( i mean how could we see ??? ) :kidding:

[runfiverun]

look at your alignment pins.
I'd bet one is sticking out further than the other, allowing the mold to open unevenly and twisting the 2 halves out of alignment.