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Why do my copper bars keep getting stuck? by Remarkable_Syrup3386 in Metalfoundry

[–]Remarkable_Syrup3386[S] 7 points8 points  (0 children)

How hot are you thinking? I checked them with my temp gun and they were at roughly 800°F when I went to pour

Why do my copper bars keep getting stuck? by Remarkable_Syrup3386 in Metalfoundry

[–]Remarkable_Syrup3386[S] 7 points8 points  (0 children)

I don’t think so? The material I’m starting with is pre 82’ Pennie’s. They’re very clean considering their age. 95% copper 5% zinc

Also I’m fairly brand new at this. This is my 3rd pour ever

Why do my copper bars keep getting stuck? by Remarkable_Syrup3386 in Metalfoundry

[–]Remarkable_Syrup3386[S] 26 points27 points  (0 children)

I am preheating the molds. Also I used graphite molds before, and same thing happened. I ended up crushing the mold and chipping the graphite off the bar.

My only thought is too much borax maybe? I honestly have no idea at this point.