Jack:
	The pot, from what you explain of the obsolescence of it, may be
old and breaking down as iron filings. Check the surface of the pot next
time you empty it. It may be time to buy a new one.
	Regards,
	Ramon 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Evans
Sent: Wednesday, March 21, 2007 11:57 AM
To: [log in to unmask]
Subject: [TN] Whisker contamination is solder pot

Hi Folks,
We use a small solder pot with a nitrogen atmosphere to pre tin
components. 
We are using Kester ultra pure 63/37 bar solder at 260C (500F) and
tinning in the neighborhood of 500 components per month, then the solder
is changed. 
The problem that we are seeing is some kind of contamination in the way
of very small, fine, hairlike, polarized metal stuff.  Analysis of this
stuff claims that it is copper or iron, but we can't get a real good
sample to know exactly what it is. Kester has been sent samples and they
have come back with nothing and I have had an outside lab, as well as
our own look at this solder with nothing definitive as to what it is or
where it comes from.  I have tried three different lots of solder and
the problem continues to show up on  a random basis. Our tinning pot is
obsolete and I can't go our and buy a new pot, so that option is not
available.  Just wondering if anyone else has ran into this problem and
possibly found a solution?

Thanks,
Jack Evans,
Aeroflex Colorado Springs

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