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-----:Soldering Brass -- Discoloration Problem
Quickstart:
Brass is an alloy of copper and zinc. But various actions can cause a degree of "de-zincification" such that some of the zinc is dissolved, leaving a copper-rich surface. This is sometimes manifested as a copper-colored or pink discoloration.
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Q. WHEN SOLDERING .032 BRASS TO .032 BRASS USING A 60/40 FLUX CORE SOLDER ALONG WITH STAY CLEAN SOLDERING FLUX THE BRIGHT BRASS FINISH WILL DISCOLOR TO A PATCHY REDDISH COPPER COLOR IS IT POSSIBLE TO GET THE BRASS TO SOLDER WITHOUT THE DISCOLORATION? WE USE A HIGH WATTAGE SOLDERING IRON.
THANK YOU,
ROBERT HERMAN- PORT ORANGE, FLORIDA
2003
A. Sounds like you are burning or etching away the zinc in the alloy.
Check with a brass supplier regarding the proper solder and temperature to solder this material as it sounds like it is possibly getting too hot.
A protective coating over the brass around the joint may help, as may heat sinking the metal nearest the joint. Kool Jool ⇨
(a jeweler's compound for protecting stones and fittings near solder joints) is one possibility.
Charles M. Barnard
- Menomonie, Wisconsin
Q. Is there a way to remove the copper that has come to the surface after soldering brass?
Jann Greenland- Little Rock, Arkansas
July 31, 2009
A. Hi. In response to brass turning pink, on thread 351/45 Goran B. suggested trying ammonium citrate; Liz G. followed his advice and said her components turned back yellow. It's certainly worth a try 🙂
I'm not sure if it's practical, but it it possible to bright dip the brass, which may get it back to a nice color. Many types of bright dip are available, but the most popular is probably the proprietary sulfuric acid + hydrogen peroxide formulations. I'd suggest asking a plating shop to do a sample, as that way you won't have to learn everything all at the same time 🙂
I haven't done such soldering and experienced such a problem, but from book knowledge it seems more likely to me that the flux is the culprit rather than the soldering temperature; for one thing, brazing can produce a nice brass color despite its higher temperature.
Good Luck & Regards,
Ted Mooney, P.E.
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