Zinc flux

[Double D]

I finally heard from my friend in SA who works with zinc.  Here is his flux receipe:

Take 6kg river sand mix with 1kg zinc chloride add 4kg magnesium chloride with1kg ammonium chloride. This should have the desired effect as claimed by my supplier but keep off the ground if it gets damp it begins to melt, then its ruined

[cannonmn]

That's nice to know, and I hate to sound dumb, but exactly how is it used?

[carronader]

Hope that ain't some potion for polishing DD...........I must be dumb too........come on DD.........give !  what is it ?

[Max Caliber]

Sounds like a formula that a zinc producer would use to make chemically pure zinc. A lima bean size piece of candle wax or paraffin wax mixed into 3-4 pounds of molten zinc would do what we need in casting projectiles.

[KABAR2]

Didn't we see this stuff used in a movie dealing with time travel?


Oh Wait! that was a flux capacitor........

[Double D]

We are working with 15-20 pound pot of zinc and the wax doesn't work. 

John, you use it just like you use paraffin or sawdust on top of molten lead to remove the impurities and oxidization.  We had some issues with it when we were melting zinc for our round balls at the Montana shoot.

[Max Caliber]

DD, usually zinc does not have to be fluxed or degassed like aluminum or brass.  Most of the dross will float on top and can be skimmed off.  If you're having problems with dross, you might check your crucible.  May need to use a stainless or graphite crucible.  Your crucible should be used only for zinc and nothing else.

[Double D]

Crucible is mild steel and only used for zinc.  The problem seemed to come from drips. drops, over runs and sprues.  The seemed to carring a lot of contamination.

[GGaskill]

Some of the drips, etc., made it to the ground (we were casting over bare dirt) so they must have picked up contamination from that source.  The zinc ingots I brought were fresh, commercial die casting material.  No melted carburetors in there.   

[BoomLover]

I have cast in small units, and the dross as you call it does float to the top, once the Zinc is hot enough, so it can be skimmed off with no problem. BoomLover