Golden sheen on pewter ingots?

[Hiaboo]

Well I've been melting down my pewter that I've been getting from thrift shops into easy to manage ingots --

A whole bunch of them had this golden sheen on the bottom, so was wondering what it could be - antimony, high tin content? I searched and cannot find info so I'm posting here to see what you guys have to say.

Here's the photo - https://photos.app.goo.gl/BowrTjp1Q61fKh7w8

[Bazoo]

All mine has it. It seems to get more intense as they age.

[OS OK]

I had that occur when I did a large batch of 60/40 solder into ingots. As you can see it only yellowed in the larger ingot moulds (cupcake pans or some such thing?)
I think it may have to do with the coating on the pan? All this 60/40 was done on the same day.

https://i.imgur.com/joSG6uP.jpg

[Bazoo]

Mine is ungotsni got from the forum. Supposed to be pewter. But I’ve had it a while and it’s starting to get darker.

[imashooter2]

Never had gold on mine and I’ve melted many hundreds of pounds. Always beautiful silver.

http://imashooter2.com/pictures/pewz1.jpg http://imashooter2.com/pictures/pew6s.jpg

[kevin c]

I have seen that color on occasion, but it's not consistent, not even in the same batch, poured into the same molds at what I think was the same temperature.

ETA:

And those Potter ingots sure look yellow to me, imashooter2!

[NyFirefighter357]

From what I have read it's tin oxidation caused by the alloy being too hot. I have a 1lb Lyman ingot I got somewhere that looks like a gold bar. Here is one thread about gold tone ingots https://castboolits.gunloads.com/showthread.php?401079-How-much-tin-to-cause-gold-color

[Retumbo]

From what I have read it's tin oxidation caused by the alloy being too hot. I have a 1lb Lyman ingot I got somewhere that looks like a gold bar.

This, happens when it gets too hot

[William Yanda]

I heard it described as tin oxide. That is consistent with a) higher temps, b) coating on quality drill bits and, c) my experience with pewter. I cast ingots from hallmarked pewter, sometimes I get the gold, sometimes I don't. Thinking back, temperature seems to be the variable.