Frosting only in the middles

[abunaitoo]

I casted a bunch of boolets over the last week.
Noticed that if I didn't really cool down the mold, only the middle of the boolet frosted.
I guessing it's telling me it's to hot only in the middle of the mold.
Probably because the handle is in the middle and heating is uneven.
Boolets drop from the mold fine.
I try to keep the lead temp around 700 or less.
Bottom pour Lyman pot.
Is there a trick to cooling the middle of the mold????
Trick to keeping the temp of the mold more consistant????

[Bird]

Here is my opinion based on my limited casting of 2 different styles in two different iron molds.
The handle in the middle has little or nothing to do with it.
Pot temp will not solve your problem, all it will do is heat up your mold slower or faster over a given period of time, it will also vary your bullet diameters, larger with cooler pour temp, smaller with hotter pour temp.
There is no real way of cooling the middle of your mould that I know of, but that is not really your problem. If your are casting large diameter bullets in a 2 or more cavity mould, the lead will always be hotter in the middle of the bullet, as there is less surface area for heat to tranfer to the rest of the mould.
The trick to keeping the mould temp more constant, is to get the top of the mould and sprue plate hotter as it is running too cold. This will give you even frosting from the center of the bullet and up to the base. Once you get to that stage cooling the mould a little on a damp sponge between cast will regulate the temp. I always cool the base of the mould, but never cool the sprue plate or top of the mould. In fact, I have trouble keeping the top of the mould hot and always pour extra lead onto the sprue plate.
If you water quench your bullets that you have cast, you will find the diameter at the hottest point will be smaller than the base. On my .458 mould I can measure a difference of 0.0005'' smaller at the hot spot, which may, or may not affect what you want to do with the bullet. I think that is why the large caliber and heavy bullets are made in single cavity moulds for more even heat dissipation.
What mould and bullet are you casting?

[Tatume]

Run the pot a little bit hotter, and cast a little bit faster. You should warm things up until you have a light, uniform frosting all over the bullets. Frosty bullets are good bullets.

[popper]

You are correct, usually happens with long rifle boolits. Doesn't seem to bother anything. Just cool the bottom if you want.

[Greg S]

I've had the same problem I'm working through with a Mihec 475 mold. If I preheat too much, the bands frost yet the lube grooves are fine. Mold temp appears to be a delicate balance.

[abunaitoo]

Mold is a Lyman 457193 single cav.
It's a kind of long fat boolet.
I do use a wet pad to cool the mold when the boolets start sticking in it.
Also cool it when the puddle in the sprue takes long to harden.
When cooling I start on the bottom, go to one side, then the other.
I'll try and just cool the bottom next time.

[44man]

Ignore time for the sprue to harden. It is timing after casting and what does a few seconds matter?
I cast at 750 for all. Time to cut varies for mold temps is all.
You have a hot spot and cooling a mold is doing it. Plates must be kept hot. To speed sprue set up is not in the cards. Let it go and don't set the mold bottom on a wet rag. You are defeating yourself.
Frosted all over is not bad but will give you smaller boolits and more out of round. Too hot is not good. Timing between casts is where it is and slower can be better. You might make 10 more boolits then I do in the time but mine are perfect while you dump more back in the pot. I can cast 20# of lead without a reject and might get one in a while. I can fill a mold and step out the garage to pee and continue. I have run 3 two cavity molds at once.
Cooling a mold is nonsense.

[fatelvis]

I can fill a mold and step out the garage to pee and continue. I have run 3 two cavity molds at once.
Cooling a mold is nonsense
I agree with 44 on this. After filling a mold, time is much less a factor as after you dump your boolits from the mold. I know this because I pee many times during a long casting session! Lol

[hutch18414]

Look for a thread by Goodsteel called consistency applied. It gives some interesting information on molds, timing and how to achieve consistency. It helped me a whole bunch. And 44man is correct, doing them all perfect with your timing is a lot better than throwing half back in the pot.

[44man]

I agree with 44 on this. After filling a mold, time is much less a factor as after you dump your boolits from the mold. I know this because I pee many times during a long casting session! Lol
Yeah glad the door is a few steps with no neighbors. Mostly split pee with half on a boot! [smilie=1: