Dave,

Possible problems that you might encounter are:

1.  Lower viscosity with solder/adhesive due to moisture contamination

2.  "Pop corning" of adhesive during the oven process due to moisture
pockets getting trapped inside and exploding when heated.

3.  Board processing problems due to moisture absorption


If you keep encountering these problems, try a convection oven to "bake out"
your moisture prior to oven processing or, if possible, set up a "bake out"
zone on your oven.


-----Original Message-----
From: David Hipp [mailto:[log in to unmask]]
Sent: Monday, August 14, 2000 9:12 AM
To: [log in to unmask]
Subject: [TN] Excessive Humidity


Hello.

With the Midwest summer in full swing, we're having trouble staying below
our requirement of 65% relative humidity.
Our assembly area is in the basement and we have two store-bought
dehumidifiers running full bore in addition to the building's HVAC system.

My questions are:
1) What are the possible problems with excessive humidity? What should we
look for?
2) What can we do about the possible problems until the humidity goes down?

We build and repair class 2 and 3 board assemblies. We use single and double
sided boards and hand-solder.
Throughput is 80 - 100 boards per month.
Components and boards are stocked in plastic bags (static dissipative, if
required) in the same assembly area.
Occasionally we fire up the old Electrovert for a large batch of boards
(about once every two months).


Regards,
Dave Hipp
Woodward Aircraft Engine Systems
Electrical Production Engineering
(815) 639-6732
FAX (815) 639-6040

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