Thanks, Rudy,
Gaby
  ----- Original Message -----
  From: Rudy Sedlak
  To: [log in to unmask]
  Sent: Saturday, July 05, 2003 1:37 AM
  Subject: Re: [TN] Nickel separation


  Gabriela:

  We saw something which I suspect is related to this often in the old days of fusing Tin/Lead on the PCB...and I would bet the cause of the problem is what is causing your problem.

  In the old days, they would immerse the board into a fluoboric acid solution then into the (fluoboric based) Tin/Lead plating solution, and we saw non-adherent Tin/Lead deposits (they were called "dewetting") if the Fluoboric acid pre-dip had enough Copper, and the boards were left long enough.

  The Copper in the fluoboric acid pre-dip would react with the Copper on the boards to create an insoluble (and invisible) Cuprous salt deposit on the Copper.   You could plate over it, but the plating was non-adherent.

  Suspect the same may be happening to your board... The fabricator is parking the board in an acid pre-plating dip, and not changing the acid dip often enough, and picking up Copper in the acid, which is causing you your problem...

  And remember the wise words someone once said, "Free advice is often not worth what you paid for it...:-)"

  Rudy Sedlak
  RD Chemical Company ---------------------------------------------------
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