Removal of flux
 

Any recommendations as to which solvent to use to remove solidified residues of flux from silver soldering (brazing). Most of it forms a glass like layer that will crack away when using a scraper. However, some of it is hiding in pores left behind after removing rust. I would like to use a suitable solvent and the miniature wire wheel on the dremel.

So which solvent?

Re: Removal of flux
 

It's important to remove the flux as it is corrosive. However, I don't believe there is a solvent that will remove it. All you can do is chip and sand blast .

Re: Removal of flux
 

The best way to remove soldering flux is to use a mixture of water and baking soda. make a saturated solution and then scrub the flux with a red scotch-brite pad and the mixture. This will lift the flux and neutralize it in one go. Then rinse the clean area with clear water and dry. If your body soldering then you need to wash the area with lacquer thinners as a last step to remove the lubricant from the paddles. Then your good to prime.

John Poole

Re: Removal of flux
 

The flux eyestein is talking about is boric acid which turns into a glass like substance. Its very different from the flux that's used for soft soldering.

Re: Removal of flux
 

I agree with the sandblast. That will also leave the surface better for the paint to adhere to.

Re: Removal of flux
 

Just go to an auto body supply store and get a mule Skinner brush. They are a 2" brush with epoxy molded in the bristles. They come with a Mandrel and brush. After you have the mandrel you can buy just the brush. Use them in 1/4" drill. Mule Skinner
is a brand name so sometimes they don't use that name. They work very well for cleaning up welds rough metal etc.

Re: Removal of flux
 

There is a product we use on aircraft wiring that is a thread like material that wicks the flux off like magic.
I'll get the product name and repost, I have some in the garage...but damn if I can find it right now.

Re: Removal of flux
 

Be aware that using solvents to remove borax flux could result in the solvent getting in places it can not be reached to be completely neutralized.

There are chemicals that will remove the flux but you had better research that yourself.

Re: Removal of flux
 

Funny it works for me on Silver Solder.

JP

Re: Removal of flux
 

Quick Braid
Rosin
mfg. by
Easy Braid
Cat.No. Q-B-5AS

We use this item on military heavy's, (bombers/tankers/E-3's/E-6's) it's a flat copper like thread that comes in a little blue spool, heat the area with your solder gun touch the braid on it and it wicks the old solder and flux right off the contacts like magic, clean and ready to go again.
I'm sure there is a civilian equivalent, if not this particular product,
for sale at fine stores that sell solder and solder accessories.

Re: Removal of flux
 

AKA solder-wick

Re: Removal of flux
 

We use Quickbraid all the time here, it's a normal consumer product.
However, I highly doubt rosin soldering braid will do anything to a silver soldered product. You silver solder at 1400+F not 650. I think when I solder using Stay-Silv 15 I'm over 1600F. The nice thing about Stay-Silv 15 is for copper to copper joints you don't use a flux.

I've also never seen it remove flux but could be wrong there.