Julie,



This tinning pot is used exclusively for tinning copper Litz wire.  Pot would usually be set to max temp and allowed to be on all day, 5 days a week.  Brilliant!  Stuff at the bottom is so hard it kills carbide drills and dulls chisels when attempting to dig it out.  This pot is supposed to hold about 2 pounds of solder.  When I got it, it might have held only about 1/4 pound due to the stuff caked into the crucible.



Phil



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Julie Silk

Sent: Wednesday, March 15, 2017 1:37 PM

To: [log in to unmask]

Subject: Re: [TN] grunge at bottom of tinning solder pot



I agree with Dave that it's likely to be an IMC.  What are you tinning?  Back in my first job in printed circuits in the through-hole days and when we used gold-plated boards, I was engineer for a drag solder machine (note that I did not pick this equipment, and do not advise it).  We had to lower the temperature in the pot, let it sit for a while, then dredge out the gold-tin intermetallic from the bottom of the pot.  You should definitely have this stuff analyzed if you've been pre-tinning gold parts.  It could have some commercial value.