Borax

[solvability]

I heard adding Borax to the pot will pull undesirable impurities. I added some to a pot of what I was told was metal from wheel weights and it pulled up a good bit of something, but I am really not sure what.


Anyone know about Borax - Boric Acid?

[tall grass]

Solvability

I don't remember what the chemistry is on these two but they are different. Borax is found in the laundry section and boric acid is found in the cockroach killing section of your favorite place to shop.

regards


Jim

[runfiverun]

borax is the 20 mule stuff and also the white powder stuff you get from marvelux and midway.
anyways it will form a glass like air barrier on an alloy helping keep oxidation to a minimum.
which is how it works as a flux by creating an oxygen free barrier alowing oxides to return to an alloy.
it will also pull some heavy metals [nickel] from an alloy and trap them in that glass like hardness, unfortunately it will also do the same thing to tin.
it also does not have carbon to create a carbourization affect in the alloy helping clean it, and also helping the alloy [SbSnPb] chain form more readily.
thats about all i can think of that i know about borax at the moment.
hope this helps some.
i have successfully used borax to alloy antimony ore into a tin richened alloy through use of the oxygen free zone and temperature control.

[Defcon-One]

How about Sawdust? Better and complete flux! Easier to get!

[cbrick]

Welcome to CastBoolits solvability,

Here's a link that will explain the chemistry of Borax as a flux and how it can clean an alloy but do nothing to reduce tin, only remove it.

From Ingot To Target: Chapter 4, Fluxing the Melt

It will remove tin just as effectively as it does what you would consider contaminants. It will also gunk up your pot to the point that a stiff wire wheel in a drill motor is needed to remove it. When you get to the point that this is needed wear a quality dust mask, the clouds of fine black dust are pretty nasty.

I used Marvacrap for years right up until I took my head out of my hieny. Won't allow the stuff in my shop ever again.

Rick

[geargnasher]

+1 as usual, Rick. It is criminal that borate fluxes were ever foisted upon the boolit caster.

Gear

[hiram]

A little off the topic, but borax can be used as a flux when brazing.

[solvability]

Thanks guys - looks like it is pretty useless for the desired purpose.

[geargnasher]

A little off the topic, but borax can be used as a flux when brazing.

And for that it does very well. The borate glass that hardens on the surface of the weld turns dark with impurities that it pulls out of the base metal sometimes, sometimes it's just clear, depends on the base metal and how clean you got it.

Gear