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rampa_room_artillery
12-16-2010, 09:23 PM
any thoughts on making a mold out of aluminum for a zinc projectile. 6 inch round stock for a 2.25 projectile. ??? I think it will be ok , my smith mold is aluminum and it works great.

what do you guys think??
rick bryan11434

John Wells 3rd US
01-22-2011, 03:21 PM
Zinc alloy casting temperature is too high to use in an aluminum mold. I've done it. After a lengthy pouring session, the part of the mold directly below the sprue starts to degrade/erode due to constant impact of the stream of hot metal. Zinc alloy needs an iron mold for durability. Lead alloys cast well at temps 100-150 degrees below zinc, and even then, the hardness of the aluminum is notably decreased while the mold is hot, according to articles I've read.