Trouble with aluminum molds (sticking)

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iraiam

New member
I am new to aluminum molds (Lee), so far I can say I much prefer the steel Lyman molds, of which I have many, and no problem operating them.

I am having trouble with the bullets sticking in these Lee molds, I have adjusted the casting temp all over, I have been re-smoking the mold every 10-12 castings, this is the only thing that has been effective. bullets come out in good quality, they just get hard to remove after about 10 castings.

I am considering trying one of the various mold release products, or just spending some money on new Lyman molds.

Anyone have any idea what I am doing wrong?
 
Solved

Yes, I lapped the molds lightly by hand with a fresly cast bullet, which I installed a sheet metal screw in and painted a coat of pumice paste.

It is considerably better now.

Thanks
 
First step with a new Lee mold: check alignment and deburr.
Second step: face the top of the mated blocks and the sprue plate with emery cloth on a piece of glass.

Third: cast with it, so you can figure out what else is wrong.

I haven't lapped one yet, but I do have a mold that would probably benefit from it.
 
I NEVER smoke any mold. Lee says to in their destructions, but you don't need to smoke any mold that's made right.

iraiam, your problem is with burrs that hang onto bullets, preventing them from releasing from the cavity.

Bullet design has a lot to do with whether it will fall free from a cavity. There has to be some taper to a flat pointed bullet, and square lube grooves are another culprit.

Some molds just have to be used to get broken in. The longer you cast, the better they work.
 
On a side note, make sure the alignment pins are properly 'staked' in the mold. I had a couple pins fall out because the person staking at the factory wasn't paying attention.
 
I have thirteen Lee molds,all I've had to do to several of mine is sand the top of the mold block with some 500 grit paper and light oil,knock a few burrs off the sprue plate or use my chamfering tool to lightly deburr the bottomof the pour hole.

I wash my molds and degrease them with mineral spirits before use and heat them on a hot play before the first cast. I lube the sprue plate and pins with synthetic 2 cycle motor oil a little goes a long way.

I smoked a couple of my first Lee mold but soon found out it wasn't necessary anymore. And as snuffy said the more you use them the better they work
 
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I use Lee moulds and have for decades. I do not smoke or lube them. I just pick up and use. The key is to make sure they are up to temp and work with a steady rythmn to make sure they stay at proper temp.
That said, I still much prefer Lyman moulds but their price is prohibitive.
 
I have several LEE molds. There is a learning curve, and once you get the hang of it the molds perform well. The other day I cast a bunch of 9mm round nose bullets. Normally I have to toss the first few castings back into the pot. This time I started casting good bullets and continued to cast good bullets throughout.

I preheat he molds on a hot plate set between low and medium. This takes about thirty minutes or so. When the mold is ready and the pot is about 750 degrees I get started. Most of the time this works very well for me.

I have never seen any benefit from smoking a mold.
 
Smoking a mold, or using a spray mold release, causes the vent lines to be plugged up. It also causes the boolit to be undersized,,--smaller that it was designed to be.

I'd like to ask John Lee why he insists on putting that in his instructions. It's never recommended over on castboolits . com, but a lot of people start out that way because the mold maker says to.

I sent a 6 cav. 9mm 124 RN mold back to lee. It was misaligned. I got back a mold that had been tested, it was already smoked. First thing I did was remove the black junk from the cavities!:mad: The replacement works just fine.
 
I've been casting a long time and I've never smoked a mould. It is un-needed. Lee moulds work very well but there is a learning curve with aluminum moulds and with 4 to 6 cavity moulds. With proper casting technique the Lee moulds should give a good service life.

When my boolits are of a design that is prone to sticking (very squarish) then I run a little hotter and this helps with it, especially the Miha HP mould with the pins. With the 4 to 6 cav moulds you will want to preheat the mould and when you begin casting with it, only use the two cavities nearest the sprue cutter hinge for a few casts and then use the next two cavs and so forth. This seems to help bring the mould up to casting temperature easier than trying to begin filling all 6 cavs. and saves on handles too.
 
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