Silversmithing
(c) 2005 Jerry Davis

Notes about Flux

I think the type of flux a person uses in soldering is almost as important as practicing the soldering process.  I struggled for years with Battern's Flux and others that dried to a "popcorn popping" state while I tried to keep pallions in place.   What a frustration.

The following information can change one's success in soldering in a positive direction.  I wish I had known these techniques years ago. 

Use home-mixed spray flux (Ethanol and Borax):

The spray flux while burning off the alcohol will preheat the silver and allow the heaver paste flux to melt into the joint better.  The coating of powder flux will give some protection from fire scale. 

The ethanol I buy is completely denatured. HUMCO Formula 19-190 proof it is 90.5% ethyl alcohol. Denatured with some other stuff such as Methyl Isobutyl Ketone (which doesn't really matter which chemical it is denatured with).   You dissolve at room temperature all the HUMCO Boric Acid powder you can in it at room temperature.  You want a saturated solution with some that will settle to the bottom.  After you are certain of a saturated solution, let it settle and carefully pour off into a spray bottle for use.

Heavy flux paste known as Stay-Silv:

The heavy flux paste that I use does the cleaning of the joint to be soldered.  The cleaning can be seen as it is heated to 800 degrees.  You will see it flow and clean.  It looks like solder flowing but isn't.  You learn to use this as a temperature gauge while heating.  The flux I think is the best in the world, is a white brazing FLUX named Stay-Silv part no. 40021 bought at welding suppliers.   Use distilled water drops mixed with it to keep the consistency wanted.  The methods I now use don't require cleaning of the silver before soldering.  An amazing time saver.  I no longer pickle between every solder.  The flux will do the cleaning.  Put liquid paper where you don't want the solder to flow.

Handy Flux paste from Rio Grande seems to be the same flux.

For best results and longer lasting pickle, use distilled water to mix with Rio Pickle.   Tap water always has some iron and will shorten the life of pickle.  Properly mixed Rio Pickle can last for days with proper use.

PS:     I mentioned the HUMCO brand only because it is the one I happened to have bought at the drug store.  Other brands with the correct percent and purity should work as well.

 

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