We have a number of printed wiring assemblies that are showing
indications of bad (?) solder mask.  Tape test is fine on PCBs prior to
wave solder. And overall appearance prior to wave solder appears normal.

After the wave soldering process, boards are water washed and dried.
There is a powdery, whitish, streaky look to the boards.  This does not
come off, and it apparently is not on the surface.  It appears to be
inside the solder mask.  Tape test still passes, no blistering or loss
of adhesion is apparent.

The customer wants Class 3 standards to apply, and cosmetically this
looks terrible (yes, 610-C says okay - but also says customer must
determine what is acceptable).

Checking with a third party board house, we are being told this may be
caused by the solder mask not being applied over  clean PCB, or improper
mixing of the mask and catalyst.

Our concerns are: what is the long term consequences - will this break
down, allow growth of something, or what. The boards are used in power
distribution systems for 19 inch computer racks.

Any help would be appreciated.

Tom Parkinson
WinTronics, Inc.

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