First results are quite encouraging. I was told by the helpful folks
at Boston Scientific that 1 gauss is an acceptable level of field
strength for 60 Hz fields. I don't know if that's RMS or peak to zero,
doubt if it's that precise. Being medical and actually in print, it's
probably quite conservative.

I did two experiments with MIG today. Machine is a Millermatic 210. I
had it set at where it seems to run well on 1/8" mild steel which is
what I mostly MIG. Settings were 3 on voltage knob, 50 on wirespeed.
I'll have Mary read an ampclamp tomorrow while I'm welding, but
current is whatever it is. I'd guess about 150 amps.

Cables were dressed fairly carefully. The sensor was clipped to my
shirt near my left shoulder. I welded in normal position at normal
distance, which is with my chest maybe 18" from the puddle.

On the first run the peak value recorded was about 1 gauss. I moved
the groundclamp to within 6" of the weld zone. Then the peak value
recorded was about 0.38 gauss.

This setup (or lower current for thinner metal) would do about 90% of
what I do with MIG. I have welded heavier stuff, but not often. Now
I'll get help if/when I need thicker stuff done.

I hope things go as well with TIG. I'll be trying that tomorrow.