Stearic acid for flux

[snuffy]

Somewhere on this forum in the past, people have discussed the use of stearic acid for fluxing casting alloys.

I was at a hobby lobby looking for candle making supplies. Specifically, for some sort of emulsifier for paraffin wax. I spotted a pound of stearic acid for 6 bucks. I remembered the discussion here, so I bought it.

Doing a search, I see I can get it for 15 bucks for 10 pounds.

WOW! It works better than anything I've ever tried. It's nice that it's a powder so you can scoop a bit into a spoon to stir into the alloy. It smokes a lot, but igniting the smoke with a lighter eliminates the smoke.

I've been using the wax that midway sells, the blue stuff in a cardboard tube. It works, and I wonder if it may have some stearin in it. Once this pound is used up, I may get some more. It's uses in candle making are many, as well as being useful as bullet lube hardener.

[snuffy]

Ya, here's where I saw it!

http://castboolits.gunloads.com/show...ht=steric+acid

[gyrogearhead]

Hi,
I've been lurking here for several months now learning all I could and trying my hand at casting from time to time. One question I have that I don't think has been resolved on the discussion boards yet is:

Does powdered pine rosin flux Boolit lead as well as stearic acid or sawdust?

I know that sawdust has the added property of forming a protective blanket over the melt to slow down the oxidation. That said, from a chemical standpoint would a "pre-treatment" of rosin or stearic acid make the sawdust more effective? Would a mixture of 50-50 rosin and stearic acid be even better? And lastly, what about mixing it all together with a little candle wax in a plastic ice cube tray to make "Flux Candy" pellets that could be tossed into the melt as needed?

I tried the ice cube tray buisness mixing pine sawdust and candle wax, putting it in a tray that makes 1/2" ice cubes and using the resulting cubes to add flux during my last WW smelt. It worked pretty good but I'm not satisfied it got as much of the tin oxide back into the melt as I would like.

The friend I cast with who has more experience than I showed me the ice cube tray trick but he used parifin and stearic acid in his mix and no sawdust. It seems to me that came out with a cleaner melt than wax and sawdust (less dross after fluxing).

You guys have all the experience. Anyone been down this road before and if so what did you discover?

Gerry