Author Topic: More zinc casting questions (Read 687 times)

threepdr · « **on:** March 11, 2005, 04:18:37 AM »

I have a aluminum mold for making fishing sinkers. It casts a 2 1/2 inch ball which is just about right diameter for my 3 pounder gun. However, the lead balls from this mold are much too heavy for the gun.

Can this mold be used to cast zinc balls? Also how hard is it to melt zinc? Can I used a lead melter for that or can I melt zinc on a propane burner?

I've cast alot of lead bullets in my time, but have never experimented with anything else.

Here are some pics of the gun

http://community.webshots.com/album/231133419pBaOUJ

GGaskill · « **Reply #1 on:** March 11, 2005, 09:23:37 AM »

Pure aluminum melts at 1220°F, zinc at about 780°F. Aluminum loses strength at elevated temperature, although how much strength is needed for this application is unknown. It looks like it would work but there is some risk of damaging or destroying the mould. A steel mould would be better.

Most electric lead melters get hot enough to melt zinc but once you have melted zinc in one, you can't use it for bullets again as the zinc contamination makes the lead not cast well. If you use a fire heater to melt the zinc, be careful not to overheat the zinc as zinc oxide fumes (white "smoke") are toxic. See the "Source for zinc" thread for further info on "Metal Fume Fever."

Will Bison · « **Reply #2 on:** March 11, 2005, 10:07:40 AM »

That's a big nyet on the aluminium moulds. I've done everything from small arms bullets to cannon balls with zinc. Zinc is wonderful stuff but I have learned that aluminium is too close in melt point. To get a good pour with zinc it has to be a few hundred degrees above melt point.

It never hurts to repeat, zinc is a heavy metal like lead, arsenic and mercury so be careful.

One other point, if you pour zinc into a mould with a sprue cutter don't expect the sprue cutter to work very well. Zinc is hard stuff and will lock up a sprue cutter.

savageT · « **Reply #3 on:** March 11, 2005, 12:02:34 PM »

Quote from: Will Bison

That's a big nyet on the aluminium moulds. I've done everything from small arms bullets to cannon balls with zinc. Zinc is wonderful stuff but I have learned that aluminium is too close in melt point. To get a good pour with zinc it has to be a few hundred degrees above melt point.

It never hurts to repeat, zinc is a heavy metal like lead, arsenic and mercury so be careful.

One other point, if you pour zinc into a mould with a sprue cutter don't expect the sprue cutter to work very well. Zinc is hard stuff and will lock up a sprue cutter.

Hey Guys,
SERIOUSLY, Zinc is a heavy metal I would NOT consider melting. If you do a search for safety data on zinc on Google, it should tell you that like lead, it's not something you want to breathe the vapors from.
Hate to be a wet blanket ....but lung disease is not fun!

Jim