Hello Ed. Pinholes and Blowholes, don't they every go away?
What's the temp and humidity in the plant down in Florida. Sometimes all the
baking in the world won't work for surface moisture from the local
environment. If the moisture is high also check the flux for water content,
which would take more energy out of the preheaters to get it all and it
could be blowing out at the wave.

A wild guess could also lead to investigate outgassing of the intermetallics
at the knee of the pth.  John DeVore did lots of work in this area years ago
and found that the intermetallic at the knee did outgas and when solder
joints were microsectioned void could be seen at the knee. When this
condition occured you also did not get flow up to the pad on the top side as
the outgassing prevented the solder from climbing up over the top of the pad.

Third thing to look at is non metallic contamination in the solder pot. Get
an analysis done to check out the non metallic elements.

Good luck, keep us posted.


Leo Lambert
Technical Director
EPTAC Corp.
WWW.eptac/.com 

Check us out, we can help
At 12:59 PM 4/7/97 -0400, Ed Gavin wrote:
>Trying to elimenate pinholes(many) and blowholes(some)
>
>Situation:
>Through hole technology, 0.062 double side PCB
>OA 20% solids flux, .905 spec gravity
>Wave Temp - 500*F  Preheat top side temp of 190*F
>Speed 4.5 FPM
>
>Have tried baking 215*F for 2 hours
>Have microsectioned board, copper in holes looks good
>
>Believe some components could be contaminated, could this cause the
>condition?
>Looking for suggestions
>
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