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  for Metal Finishing since 1989
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Achieving a nice finish on copper

I took a work project home (sadly, my work is my hobby...) and reached a point where I don't know where to turn. I'm the guy that the platers don't want to be bothered with - too few parts, too infrequently. I don't blame them, either. This time I have copper sheet which I have oven soldered copper tubing to. Before the soldering, both were dipped in a cold tinning solution a "stannaous tin acidic solution" that contains hypophosphorous acid, as a prep for the soldering. This worked well, but the resulting finish out of the oven is nasty. If I could get a finish like the original cold tin, I'd be thrilled. Any ideas?

Chris Loiacono
- Brooksville, FL 34601
2000

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I'm probably misunderstanding the problem completely, but ... In electronics work they 'reflow' the solder to give it a shine or restore the shine. One way of doing this is to 'float' the items on the surface of a bath of hot oil. Could your solder be substantial enough in thickness to be reflowed, and could you rig some kind of hot oil bath into your oven?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2000

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I suspect that what we're dealing with is an immersion tin deposit; I don't think that this can be reflowed. A better process in this case would be to hand tin with solder prior to going into the oven. If you need to rework, you'll probably want to strip the solder and immersion tin first.

James Totter, CEF
- Tallahassee, Florida
2000