Never tried the Teflon coated pans, but have read they are no good for ingots, over the years I have picked up heavy aluminum muffin pans, they work great.
I just read an article in one of the gun rags about using the old Army mess kits, they are stainless and broke up into 4 sections, the guy that wrote the article claimed the 3 smaller wedges drop ingots that fit nice into a lead pot, and are cheap.
But the aluminum pans can still be found at yard sales or goodwill stores cheap.