Have not seen this before

[fastfire]

105958The boolit Lee 312-155 I use 2 2 cavity molds that do this. Why 2 molds, that's another story. One side of the boolit is nice and shinny, the other frosted in the center area.
I have tried these molds now for 5 sessions. Temp ranges from 680 to 750. All with this frosting in the same place each time.
Cleaned the mold with dish soap and tooth brush, many times also used brake cleaner and (white gas which Lee recommends).
Using 75% COWW 25% Lino spacers.
Have 2 Lee 20 lb pots hooked up to a PID.
Seems there must be a substance on the mold surface that is causing this, that's the only thing I can figure............

[RickinTN]

Just on a hunch here but do the frosted side of the bullets come from the side that adjoins the other cavity or in other words from the middle of the mold? This would be the "hottest" part of the mold because it's getting heat from both cavities. Sounds like it is the beginning of frosting, and I would suspect it to begin in that region of the mold. Two suggestions would be to cast only one cavity for a few bullets and see if it goes away. The other would be to slow down just a touch and let the mold cool for 15 or 20 seconds after the bullets are dropped.
Hope this helps,
Rick

[fastfire]

Both cavities get the frosting on the side towards the handle.

[trapper9260]

I say slow down on your casting and let the mould cool down alittle and see if that helps.But you can still use the boolit still if it have some frost on them .Test in a round and see how they go .I have use some that had some frost on them and had not any problem for how they shoot.

[fastfire]

If I get the mold any cooler I get wrinkles and rounded corners.
The frosted areas are a bit of a depression in the side of the boolit.
So far I have got the mold hot enough to get completely frosted boolits a couple of times, but it is a ruff kind of frosting.

[Tatume]

Speed up your casting so the mold gets hotter. Bullets should be uniformly frosted.

[243winxb]

Vent line problem? Return to Lee.

[zuke]

Speed up your casting so the mold gets hotter. Bullets should be uniformly frosted.

I agree