Blair, if you are tinning stranded wire, your pot temperature should be  500 +/- 25 F. The reason is that that is the ideal alloying temperature for tin/lead solders. If the pot is being used to remove enamel (magnet wire)insulation and tin wire at the same time it will need to be run at a higher temperature, per the wire manufacturer's recommendations. Tin/lead solders oxidize rapidly when in the molten state therefore dross formation is normal. If you are concerned about the color of the dross, it may come from your atmosphere or what you are tinning. If it is a small pot why not just dump it and refill it with fresh solder.

Ron Dieselberg
Trainer/Auditor
CMC ELECTRONICS
CINCINNATI
[log in to unmask]


-----Original Message-----
From: Hogg, Blair K. [mailto:[log in to unmask]]
Sent: Wednesday, October 23, 2002 17:27 PM
To: [log in to unmask]
Subject: [TN] Dross on Solder Pot


Hello Technetters,

I'll readily admit that I'm not an expert on solder, and something has been
bothering me lately here at the shop, so I'll see what insight the forum can
yield.

We have a small solder pot used for tinning wires in our harness area.
Periodically as I walk by this pot I notice fairly thick black dross
covering the surface of the solder. This gets wiped away before they tin
wires, but lately I've noticed it turns brownish fairly quickly after wiping
off the dross from the surface.

What can be the typical causes of this? Could the pot be too hot? Could the
pot be contaminated (e.g. with copper)? Could it be contaminated because
it's too hot? I'm suggesting heat here because they run this pot at a fairly
high setting, I'm not sure why.

Thanks,

Blair Hogg
QA Manager
GAI-Tronics

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