jim rozen wrote:

In article , Jeff Wisnia says...

I think it could well be...The resistance (cold) of No.12 wire is 1.6 ohms/1000
feet, so the four inches or so of copper tip on my Weller would have a
resistance of only about half a milliohm. (And I bet if I actually measured and
calculated the tip would be closer to a piece of No.10 wire, so even lower.) The
pressure contacts are brass on copper, socked down damn hard. Consider
that...'eh?

And those guns won't work if the nuts aren't 'squeaky tight.'
My former boss actually calculated what was optimal - and it
turned out to be 5.25 inches of no. 14 wire for the tip,
bend into a hairpin shape.

Jim


snipped

Now you've got me wondering what approach he took when "calculating" that length. If
I had a "need to know" that fact I'd probably just do empirically by trying a few
different lengths of wire and measuring their dissipations with the same kind of
current/voltage measurements I barfed off about earlier in this thread. Then, I could
plot power vs. wire length and find the max.

Or maybe one should shoot for maximum tip temperature, or...or...or...

Jeff (Who abviously has *way* too much time on his hands this week...)
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the
blame on."