You think this is zinc or some other type of contamination?

Just saw this in the facebook marketplace. I've "smelted" quite a few wheel weights into ingots and never seen cratering like in these pics. Im not buying them so it's not really a concern. I just get curious sometimes and try to learn so thought I'd run it by the experts here Attachment 293165

That happens when you have new non stick muffin pans. Something gasses off and causes craters on the bottom

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Originally Posted by Michael J. Spangler

That happens when you have new non stick muffin pans. Something gasses off and causes craters on the bottom

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Oh ok thanks. Ive not used new pans, which would explain why Ive not run into it before.

I get that sometimes when pouring the first couple ingots in a cold pan. Please, no comments about the tinsel fairy. I am well aware of her.

Quote:

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Originally Posted by Michael J. Spangler

That happens when you have new non stick muffin pans. Something gasses off and causes craters on the bottom

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^^^^correct^^^^ For my purposes and my OCD, I took a propane torch to my pans burning/cooking the coating and no more off gas cratering.

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Originally Posted by oley55

^^^^correct^^^^ For my purposes and my OCD, I took a propane torch to my pans burning/cooking the coating and no more off gas cratering.

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I did that to my pans. Avoid inhaling the fumes: I didn’t and was coughing for a week afterwards.

I put my last ones on the big meltuing burner for a bit then tolled them out tin the yard for a few weeks did a nice job of getting the coatig off and got a little surface rust on them they drop right out and i get none of the craters

Agreed that, in this case, a bit of rust is your friend.

I agree with the others, thats just the non stick coating gassing off and causing voids. You might go back if the prices were fair.