Oren wrote:
On Wed, 20 Mar 2013 11:38:06 -0500, "HeyBub"
wrote:


I guess I'll stop the weld when it seems done.

I dunno. With to much heat there is risk of damaging the battery cell?

The spot welder is a better choice -- I think. I have a link to build
one from a (free) 1500W Microwave. I can post them.

No need. There must be 100 plans on the net.

The simplest seems to be the capacitive-discharge model. You charge up one
or more capacitors whose combined capacity is in the neighborhood of 1 Farad
(with a 12-24V battery charger) and discharge the pack through the substance
to be welded.

There's more to it, of course. The switch is a Thyistron that can handle
2400Amps, and it, in turn is driven by a 12v wall-wart and a doorbell
switch. The electrodes are copper rods, and so on. Parts, however, should be
less than $100.