lead build-up

[fishboy747]

Can I get some help with a problem that I seem to be having with mt mihec mold. I am getting a bit if lead between the sprue plate and the mold on both surfaces. What can I do to prevent this and any help is appreciated. Thanks

[onondaga]

Smear on the sprue plate or mold block top is usually caused by too high heat somewhere; mold blocks, sprue plate or alloy. Opening the sprue plate too early can also cause smear because the metal isn't cool enough to shear with the sprue plate.

Cleaning the smear off and preventing it is another story.

Getting the mold hot enough to rub the smear off with a stick works but molds can be overheated and damaged so be careful. I have used a small pencil flame torch to work on a small spot. A Bernz-O Matic with the flame adjusted small would work with care.

I use clear Silicone Dielectric Grease from a car parts store and only rub in enough with a Q-Tip to spread out a shine on the mold block top and the sprue plate bottom...This is a tiny amount and will keep lead from sticking. Do not use an amount that could possibly flow into your mold cavity. Silicone grease does not melt at casting temperatures and an amount in a mold cavity will be reflected in your casting.

An easy alternative that is hard to over do incorrectly is to scribble with a #2 lead pencil on the affected area after it is cleaned. The graphite in pencil lead is a very effective anti-flux and lead bullet alloys will not stick to graphite. Scribbling is very easy also. Just blow it off lightly after you scribble, you don't want graphite in your mold cavities either.

Gary

[btroj]

Did you get a little bottle of sprue plate lube with the mould? If so, that is what you want to use. A tiny, and I mean tiny, amount on the top of the blocks will keep lead from sticking.
You also may be cutting the sprue just a second too soon. This will cause much of the problem you are having.
If you did not get a little bottle of lube with the mould I can sum up the answer in one word- Bullplate. Get it from Bullshop here and you will never have this problem again.


Brad

[largom]

Get Bullplate lube from Bullshop on this site and allow your sprue to cool a little longer.

Larry

[fishboy747]

I am guilty as found Yes I was trying to knock off the sprue a bit too soon but will just have to slow down a bit. Mihec molds are addictive the 4 cav .44 mold has been great did just shy of a 1000 and had about 100 rejects MY FAULT now to the range for some testing.

[MtGun44]

With Bullplate Lube, you can cut the sprue plate very, very soft - where it would normally
smear very badly and it will NOT smear. As a matter of fact, a smeared up mold top and
sprue will slowly clean up and be totally lead free by the end of a casting session with
Bullplate lube. You are not cutting to early, you are just not using the right lube.

Really.

Bill

[Doby45]

Spoken for truth!!! A drop goes a LOOOOOOOOOOOONG way.