Legit DIY Flux Recipe?

Hey everyone,

Looking around for some DIY flux recipes and came across this one:

90% Borax
5% Potassium Nitrate (KNO3)
5% Ammonium Chloride (NH4CI)

Anyone have a strong opinion on this recipe? I know Potassium Nitrate is used in gunpowder as an oxidizer, but that seems bad for soldering right? I’m about 10% confident in what I’m saying about that though, so please chime in.

This is more of a melting and refining flux than a soldering flux. The potassium nitrate is an oxidizer, and the ammonium chloride will help slag off impurities in your melt and toughen the ingot. This would be a useful flux for melting and pouring ingots of gold or silver to be processed into sheet or wire.

Great, appreciate the info.

Any home brew recipes for soldering flux?

I don’t think you have to bother, just use borax. It’s a tried and true method that’s been used for a very long time.

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