Silver solder flux

[hoppercar]

After silver soldering some brass tubing, what can you use to remove that hard , clear silver solder flux crust

[jkimberln]

I bead blast it off usually, but where I worked they chipped off as much as they could, then put the workpiece in boiling water until the flux was gone. The flux does eventually dissolve in water.

[Builder01]

I use citric acid as a pickle bath. It never fails to remove all traces of flux. Then scrub with Scotch-Brite or a brass brush.

David

[Fred_V]

I've used Muratic acid. but don't leave the part in the acid overnight!!

[John Hasler]

Hydrochloric acid will always remove some metal, though.

[JohnK]

The Charlie Purinton pickle recipe: 1 pound of salt, dissolved in 1 gallon of vinegar.

Keep this 1:1 ratio for whatever quantities you need. For example, 5 pounds of salt to 5 gallons vinegar.

Soak your part in it & rinse thoroughly.

[Harold_V]

The use of either hydrochloric acid or muriatic acid isn't a good idea, as the fumes are quite destructive. If you must make that choice, use the acid out of the shop, not in the shop, and don't store containers of either of them in your shop. Even well capped, they release fumes that rust exposed surfaces (like your mill table).

H

[John Hasler]

Hydrochloric acid and muriatic acid are exactly the same thing.

I agree that it should never be used indoors (unless you have a fume hood).

[Greg_Lewis]

When you run out of the white flux you might try the black stuff. It comes off much easier, usually with nothing more than hot water.

[Harold_V]

That's a good observation, Greg. I've used both types, but have never considered the difficulty in removing either one.
The black stuff is really superior, at least in my opinion. It's a little more aggressive in its cleansing action, and more forgiving of overheat. It's now my first choice.

I usually bead blast soldered items. Does a nice job of cleaning the flux and making the parts look uniform. I don't know what I'd do without my blast cabinet. It's one of the most used tools in my shop.

What John said about HCl and muriatic----they are one and the same, although often labeled differently.
When I refined precious metals, I kept my fume hood operating 24/7. Even then, there was a deterioration of ferrous items in my lab, as well as the dyed bronze anodized aluminum window frames. This occurred over a period of about 11 years, however, and I was in the lab for long, hard hours daily. The home shop likely wouldn't suffer the same degree of degradation, but then the home shop also has machines with surfaces that are far more critical of being exposed to acids that lead to rusting. Considering my experiences, I don't think I'd use HCl in my shop, even if it had a fume hood, which It doesn't. I sure miss the one I used to have, though.

H

[Sandiapaul]

I have been using this for years. Some of the comments say to heat it up, I've never done that and it still works well:

https://www.amazon.com/Sparex-Granular- ... B0058ED064

[JBodenmann]

Hello My Friends
Yes that's the stuff I use also. I keep it in a cheap crock pot on the low heat setting. It works faster if its heated.
Jack