Mould ?

[Sneakfoot]

I tried to pour some Boolits today using pure lead. Other then the thermostat going bad on my Mould Master everthing else went down hill. I kept getting voids in the Boolits. What is that little allen screw on the die used for?

[Gohon]

You talking about the allen screw on the side of the mold? The one that locks the tension adjustment screw for the sprue plate in place?

[Sneakfoot]

You talking about the allen screw on the side of the mold? The one that locks the tension adjustment screw for the sprue plate in place?

If that puts pressure on the spur plate whats the purpose for the tension spring under the spure plate screw?

[geargnasher]

Gohon didn't say the allen screw put pressure on the SPRUE plate, he explained that it locks the tension adjustment screw in place once it is set to preload the wave washer correctly.

If you don't snug the setscrew, the SPRUE plate pivot/tension adjustment screw will back out from opening/closing the SPRUE plate when casting.

Gear

[Buckshot]

..............Sneakfoot, I don't know what mould you're using but the big secret when casting with pure lead is HEAT! LOTS of it. Crank the heat up as far as it'll go and cast as fast as reason and safety allow. The only limiting factor is getting the blocks so hot it takes too long for the sprue to harden [smilie=1:

...............Buckshot

[mooman76]

Yup! What Buckshot said. A little tin can help allot too but crank the heat up and after it gets real ho you can probably turn it down some till you find where it works best.

[Sneakfoot]

Got it, thanks guys.

[mroliver77]

While we are on the subject. I find that most guys tend to run their sprue plates too tight. I run them only tight enough to take the rattle out of them. I have found that most Lyman, virtually all Lee and some RCBS and other brands of sprue plates are not flat.
I use a machined steel block 2" thick or a glass plate on top of my workbench with emmory cloth on it. I work the plate in a figure 8 and rotating it occasionally until it is perfectly flat. I break the edges of the hole with a countersink including the threaded hole in the mould blocks. If sprue hole is not sharp I sharpen them with a countersink followed by a breaking of all edges and corners.

After a preheat and a few casts I treat mould and plate with Bull plate or mihecs version of it. Casting is a dream!!
J

[theperfessor]

If it's a Lyman tension spring of the old style, it's main purpose is to dig gouges into the underside of the pivot screw and the top of your sprue plate, periodically seizing up and loosening the pivot screw.

I replace mine with stainless steel flat washers, others use 1/4" or 6mm cup/Belleville/wave washers.

[RidgerunnerAk]

Anyone have a specific temperature to put to the comment of "lots of heat" when moulding pure lead?? At some temp the lead will vaporize and become a serious health issue if ventilation is not the best. I'd like to hear a good target temp to shoot for with the pot thermometer if anyone has one. I sometimes mould pure Pb bullets for my .45cal rifles and .69cal musket.

[Old Caster]

My RCBS will only go to 740. My Waage pot will go to 805 because that's what I asked them to set it to for the top temperature and my 4-20 Lee will go to about 880 to 920 depending on which time you would like to measure it. Also the Lee will go less and less high over time and it has a replacement stat in it now that is almost new. I have molded pure at the 805 mark with ladle and it worked fine.

[whisler]

+1 on 800 deg. for pure lead

[Buckshot]

At some temp the lead will vaporize and become a serious health issue if ventilation is not the best. I'd like to hear a good target temp to shoot for with the pot thermometer if anyone has one.

............I don't believe any pot intended for casting boolits will heat lead hot enough to have it vaporize. The hottest my Lee 20# will get with just about 1.5" of lead in it is about 950º according to the Lyman thermometer. However, ventilation is never a bad idea regardless.

............Buckshot

[Sneakfoot]

I got my Lyman Mould master up to 850 degrees but had to take the cover off of the thermostat to do it and I still couldn't pour boolits without voids, then I noticed the stream of lead coming out was much smaller then the hole. I started pouring from my steel pot and in a few minutes started getting nice boolits.