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Letter 11803
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Tom Pullizzi |
Tom,
Yes, eventually gold will become a contaminant in a solder pot, and it may affect solderability. However after this point, everything will start failing solderability using the same solder pot. Not just parts with thick gold. Solder pots need to be changed regularly. In fact, it is cheaper to change most solder pots, with fresh solder, than to perform analysis to check for foreign contamination.
Karl Weyermann
- Lebanon, KY
Perhaps a good starting point is to define is how thick is the gold? Then is it too thick? Since gold is soluble in a "solder pot" assume tin/lead....60/40 ...90/10 The gold is only there to protect the solderability of the underlying base metal.i IF the underlaying base metal is free of oxides and in a "solderable" condition then the gold is the Saran Wrap to preserve it. Gold does enter the equation as it is soluble and can contribute to brittle solder joints but that gets to be blah blah blah to this situation. Dull solder from poor cooling or bad wetting angle all are another subject.
Jon Quirt
- Fridley, MN
I think, as the first poster, that it is a contamination on the surface. Usually it will be removed when running the pcb:s in an acid cleaner.
Peter Fogel
- Sweden
Hi
I'm a qc inspector, I facing the problem with the gold plating with
solderability.
If gold plating got stick with mold flash it will become non wetting
after solderability test?
Liew Siew Ling
electronics - Singapore
A few years ago, I requested gold plating on one of our PCBs as part of changing over to surface-mount technology. The solderability was terrible. I was told that gold plating above a certain thickness creates bad joints because the gold dissolves in the solder and creates a brittle, nasty-looking joint. The next iteration, I went with "Immersion gold" which is much thinner. Solderability was excellent, and we have done all boards with immersion gold since then.
Paul Boisseau
- Lexington MA USA

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