Hello Orchid family. I am having a problem with a residue after pickling on sweat soldered pieces. On the edges of the piece soldered on are left areas that seem like hardened flux that won’t pickle off. I have used Pripps flux as well as cupronil and I use Sparex for pickling. I can only get it off with a silicone disc abrasive. Am I using too much flux? I can’t figure out what is happening. Any help is greatly appreciated.
Anne Hanson
I would guess that you are not pickling it long enough. The melted flux hardens into a “borax glass” that is hard to remove mechanically. Your pickle may not be strong enough or warm enough. Notice that I said “warm.” You do not want the pickle to boil. It is not a healthy thing to breath.
Marilyn Smith
Qiuckly quenching the hot work in water will cause the glassy flux to crack and fall off.
jesse
Hi Anne. I often have the same experience especially when using Pripps and found that “pickling” with a warmed alum solution is the answer. It seems to dissolve that flux “glass” better than sparex or pool acid.
Pam Chott http://www.songofthephoenix.com
I’ve had that problem, and I’ve found the only way to get it off is to leave the piece in plain water for several hours or overnight. It will eventually dissolve.
Janet Kofoed
Actually, it’s said to be better to remove the flux before putting it in the pickle—keeps the pickle cleaner longer. It comes off just by boiling it in plain water…! It’s a whole extra step, but it works…
Janet in Jerusalem
