Flux for silver braze

Oct 25, 2010 11 Replies

I have a little "kit" from Alpha Metals that I got years ago (and sadly, I don't think they're available any more). It has a roll of silver-braze wire and a tube of flux. Originally, the flux was creamy, but over time it's gotten so stiff that I can't squeeze it out of the tube, plus, it seems to have grown some crystals that make it hard to work with.



The flux contains potassium fluoride and potassium fluoroborate; is there some way to "rejuvenate" it? I tried mixing some with a bit of water, but that didn't seem to work so well.



Alternately, is there another easy-to-get flux I could use? I only rarely need to silver-braze anything, so I don't need/want a gallon jug of something...



thanks



Isaac


Hey Isaac,

Do a Google for Handy & Harmon.

I get

but that's because I'm in Canada. Have a look at the different fluxes they offer, some of which are a powder to be mixed with water.

Take care.

Brian Lawson, Bothwell, Ontario.

XXXXXXXXXXXXXX

I've heard it called 'soldering salts'; it will soften with water, but after you apply it, you'll just have to drive off the water anyhow (the less water, the better). The only easy way to get a little more flux (if it's in a tube, the mix-water-in step is difficult) is to find an arts store that has jewelry-making supplies.

Most of that stuff is water-based, you could cut the tube open, dump the contents into a small beaker, add a little water and heat it up. You'll need the heat. Once you've got it back to a creamy stage, stick it in a wide-mouth jar. Or just go see what your local weld-supply shop has. Go easy on the water, what you add in has to be driven off when you use it. The flux I've gotten usually comes in a jar, have never seen stuff in a tube. Easy to heat up a filler rod and dip it in. Also water is easy to add. The jars are usually about 4-6 oz.

Stan

FWIW, I used plain old borax dissolved in water for silver soldering in jewelery work for years without problems. I have tried to revive commercial flux and have always been unsuccessful

I use Borax on gold and silver without a problem; the fluoride-containing fluxes are pretty toxic though they do work well. You could always drop in at your local jeweler's holding a small jar and wearing a smile....

I've heard it called 'soldering salts'; it will soften with water, but after you apply it, you'll just have to drive off the water anyhow (the less water, the better). The only easy way to get a little more flux (if it's in a tube, the mix-water-in step is difficult) is to find an arts store that has jewelry-making supplies.

************************* +1 on the jewelry flux! I get this watery flux that the shop makes in house. It goes in a sprayer and works better than anything for silver solder and brazing and I also use it with Stellite.

Plain old Borax will work well. It is not as aggressive as fluxes with florides. So clean the metal well. You can get it in a lot of grocery stores in 4 plus lb boxes. Just put a bunch in a jar with a lid and use the rest in the laundry.

=20 Dan

I have a little "kit" from Alpha Metals that I got years ago (and sadly, I don't think they're available any more). It has a roll of silver-braze wire and a tube of flux. Originally, the flux was creamy, but over time it's gotten so stiff that I can't squeeze it out of the tube, plus, it seems to have grown some crystals that make it hard to work with.

The flux contains potassium fluoride and potassium fluoroborate; is there some way to "rejuvenate" it? I tried mixing some with a bit of water, but that didn't seem to work so well.

Alternately, is there another easy-to-get flux I could use? I only rarely need to silver-braze anything, so I don't need/want a gallon jug of something...

thanks

-------------------------------------------------------------------------------- I have a jar of fluoride based flux which is now about 16 years old. It dries out periodically. I put a little bit of water in the well I created in the middle and I stir it up a bit. It is slow to dissolve. I then use the parts that have a sort of creamy consistency. It works just fine for me.

It is also useful to keep pallions of the silver wire in the flux jar to stop them from tarnishing.

-- Michael Koblic, Campbell River, BC

Or just go to the local supermarket, and buy some laundry borax! Mix to a paste with water to use. It's cheap, it works, and you get a lot of it in a box. I have been using it for over 50 years

Steve R.

I like the borax idea; I'll try that. I didn't heat the mix when I added water to what I have; I'll try that too.

thanks

Isaac

You can also mix it with cookie dough to get rid of cockroaches and ants. ;-)

Cheers! Rich

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