July 31, 2004

We had a military application wherein a tin plated box with electronics included therein had numerous tin whiskers growing therein.  Since we had numerous fielded equipment we did not want to scrap, we repaired it by cleaning off the tin whiskers and then conformal coating with Type UR. Since that was done we had no further tin whisker problems.  However, that does not necessarily mean that conformal coating prevents tin whisker growth.  It could have been that once the tin whiskers were removed, the initial whisker growth removed the internal stress, and therefore, once the whiskers were cleaned off, no further whisker growth was noted, independent of whether or not we conformal coated the box.
  ----- Original Message ----- 
  From: David Douthit<mailto:[log in to unmask]> 
  To: [log in to unmask]<mailto:[log in to unmask]> 
  Sent: Monday, July 26, 2004 10:46 AM
  Subject: Re: [TN] Tin Whiskers


  Edwin,

  NASA did some experiments and have pictures on their web site
  (   http://nepp.nasa.gov/whisker/index.html<http://nepp.nasa.gov/whisker/index.html>  )  of whiskers "punching"
  through
  coatings. I don't know if the coating "inhibited" growth (time, length,
  or amount).

  David A. Douthit
  Manager
  LoCan LLC

  Edwin Louis wrote:

  >Does anyone know whether a Polyurethane conformal coating would inhibit Tin
  >whisker growth or at least contain it?
  >
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