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Letter 16039
Plating aluminium tubing to allow
soldering
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Dear sir,
We want to solder aluminium (heat exchangers), but we can't.
According to experts, we must electroplate it first with copper. We
try to plating it with copper but not success, please explain the
process, and also what is the pre treatment for the aluminium
(zincate ? = zinc sulphate?).
Hartono Hadiprojo
steel - Cilegon, Babten, Indonesia
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Yes, you need to zincate the aluminum before you cyanide copper
plate it. In fact, you should "double zincate" it (zincate it, strip
the zincate in nitric acid, zincate it again). But zincate is not
zinc sulphate, it is zinc dissolved in caustic soda and stabilizers.
You should either buy a proprietary zincate or research the subject
via a compterized lit search. Good luck.
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Ted Mooney, P.E.
finishing.com
Brick, New Jersey
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