Andy Dingley wrote:

On Thu, 17 Nov 2005 16:20:37 GMT, "Pete C." wrote:

You most certainly can, it's essentially a current shunt. With a welder
happily pumping 200A+ through the bar, you will develop a voltage across
it based on it's resistance.

Of course you will. And for 200A current, that's about 8kW of power and
a voltage of 40mV (for a nominal "copper bar" shorting link of
0.0002ohms). To develop 2V across this sort of resistance needs 10kA,
not 200A - just how powerful a welder are we talking about here?.

You just can't get 2V across a "copper bar" - it would melt almost
instantly.

You've clearly never had any experience with a quality TIG welder
before.

Nope, my experience is all with Ohm's law.
Good on electrons, bad on bogons.

If he's going by the volt meter on the welder it most likely represents
the voltage across not only the copper bar, but also the welding leads.

Pete C.