Stearic Acid Flux

[38 Super Auto]

I had read about using stearic acid for fluxing bullet metal. Well, I tried it this weekend, and I was amazed. I was schmelting a magical alloy of range lead, WW, sheet lead, linotype, and a little solder. BTW, I ended up with 150# of BHN 10 (measured after 12 hours) ingots

I fluxed with paraffin and got my usual pretty good results. Just for grins, I added a couple of teaspoons of stearic acid and lit it off. After it all burned off, the melt surface had an incredible shiny quality that I have never witnessed (except in dreams) While paraffin, wood chips, and pine resin had always left a powdery waste on top, the stearic acid left a blackish goo that was pretty easy to skim.

It reminded me of results you get when you add rosin core solder to the melt.

I think it's worth a try.

[mtgrs737]

I keep a little bottle of it by my pot, it is also good for making bullet lube sticky so it will stay in the grooves.

[crabo]

Isn't Ivory soap contain steric acid?

Crabo

[454PB]

Isn't Ivory soap contain steric acid?

Crabo

Yes, and it works quite well as a fluxing agent. I put it in a ziploc freezer bag and beat it into dust, then flux.

[docone31]

Ivory soap.....Hmmm.
I like that idea. I use solder flux. I like a clean melt.

[38 Super Auto]

Solder flux works very well. On some alloys, after I clean all of the chaff out of the alloy, I add scrap solder. The rosin flux works very well. The stearic acid fluxing gave me similar results.

[docone31]

Acid flux has eaten the walls of my pot. The Lee pot is thin walled. I got porosity with long use of acid flux.

[utk]

Stearic Acid is not an "acid" as we know it. Stearic Acid is used for making candles and is similar to paraffin but has a higher melting point. Candles made out of this hold their shape much better than paraffin candles. Various blends of stearic acid and paraffin are common in candlemaking.

Another name for stearic acid is stearine. (I've googled these two words and found that in candlemaking these two words mean the same but chemically speaking stearic acid is a substance in stearine).

[38 Super Auto]

I assume docone is referring to rosin (pine sap based I believe) flux, as opposed to acid flux. I think some plumbers use acid flux. I have always used rosin flux for electronic and copper pipe soldering (and alloy fluxing)

[Lloyd Smale]

If you can find the old 20 mule team borax. It works real well.

[montana_charlie]

I assume docone is referring to rosin (pine sap based I believe) flux, as opposed to acid flux. I think some plumbers use acid flux. I have always used rosin flux for electronic and copper pipe soldering (and alloy fluxing)
Rosin core solder contains the 'pine sap' flux, and is correct for electronics and other copper applications. I have also used it for projects in brass.
When using rosin core, it is expected that the parts being joined are already scrupulously clean, and the flux just prevents oxidation in the solder joint.

Acid core solder contains an acid-based substance which is needed for soldering ferrous metals like gutters and flashing.
It's purpose is to etch the metals being joined, to get down to a 'clean' surface.

I wouldn't allow acid cored solder anywhere near a bullet casting operation.
CM