In a message dated 3/21/2002 10:24:53 AM US Eastern Standard Time,
[log in to unmask] writes:

<< Is conformal coating a good protection against dendrites? >>

Graham's answer is a very good one.  In a way, this question reminds me of an
advertisement that I often saw in bicycling magazines during my college days.
 It was for a new type of lock to hold one's bicycle to the parking rack, and
it had for a headline "Resists Atomic Bombs".  The key being that it was not
100% successful, but it did offer resistance.
   In every comparative test that I have ever done, uncoated boards fared far
worse than coated ones with respect to dendritic growth.  Does that mean that
conformal coating will prevent dendrites from EVER appearing?  Clearly not.
My typical tests were 100 hours at 85 C and 85% RH, with power applied, with
the acrylic coated boards normally surviving the entire test and the uncoated
boards failing in 2-8 hours, depending on the soldering process variables
involved.

Jon Moore

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