Bubbles on ingot

[Exousia]

My wife bought me a 24 mini-muffin tin to use for making small ingots. The tin has some kind of coating on it (I assume to be non-stick). I used it yesterday but the ingots came out with pits on the bottom.



My old muffin tins molded the lead normally. Do you know what causes this? Is it contaminating my lead? I like the little ingots. They weigh about 1/2 pound each.

[cbrick]

Exousia, welcome to Castboolits,

Probably the coating bubbling, boiling, flaking (something) off. Take some steel wool to the muffin tins before you use it next time to see if you can remove any more of it & see if it does the same thing.

Doubt the alloy was harmed, just flux well before using it for bullets, but then you should do that anyway.

Rick

[mooman76]

Someone else mentioned this before and it came from the same stuff. Non-stick coating. Probably getting hot and making gas bubbles. Don't look that great but won't hurt a thing.

[quack1]

I bought some well used (caked on cooking oil and grease), non coated, muffin pans at a flea market to use for ingot molds. The first couple of times I used them the ingots came out looking like yours. Once all the residue completely burned off from hot lead the ingots came out nice and smooth.

[gray wolf]

It's the coating, take a torch and burn it off.
Stand with the wind at your back the smell is nasty.

[HammerMTB]

I bought some well used (caked on cooking oil and grease), non coated, muffin pans at a flea market to use for ingot molds. The first couple of times I used them the ingots came out looking like yours. Once all the residue completely burned off from hot lead the ingots came out nice and smooth.

Same here. The coating will burn off in time and the lead is not harmed in any way. It kind of dates my ingots....

It's the coating, take a torch and burn it off.
Stand with the wind at your back the smell is nasty.

Worse than that, if it's Teflon or most non-stick coatings, they are toxic.

[Hanzerik]

I had the same thing, and the ingots were sticking. I saw someone mention grabbing some of those little stainless-steel condiment cups from Wally-World. They work great and don't stick at all, and no bubbles. I'm smelting with a Lee 10lb pot so they work ok as far as amount of lead you can use. I can get three full cups out of each pot.

[Cowboy T]

Got two muffin pans. One's coated, the other's not. The coated one produces "bubbled" ingots like the ones in the pic. The uncoated one doesn't. Both cast just fine, so no worries.

[Exousia]

Thank you all. I think I will just use it as is.

[Jailer]

Wash the pan real good before you use it and you won't have that problem.