Learned about an HF welder today

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******************* In my trade for some reason we called it 'air-arc'. Loud, hot, noisy, and very sparky. We used to keep at least 50 psi on the hose and full amps on any machine we were running. Once one got on to it, one could flush and gouge with a very smooth remaining surface. I would imagine since one is applying carbon to the base metal, one would have a heck of a time passing a bend test.
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Carbon arc gouging was invented where Tin Lizzie works. A couple of welders started a company called Arcair. The company was sold and I believe the same welders started a company that sells a metalizing system that uses two wire feeders.
Dan
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says...

snip
CAC is also handy when making (quick and dirty) full pen butt welds in thick material with poor fitup when both sides are accessible. Heavy beams can be quickly and easily sliced this way, (as always) it is easiest if weld can be positioned to make all welding slightly uphill so slag will run away from weld pool.
Just plain or J bevel (one or both sides) with CAC (or OA torch) and remove slag with quick grind, then use thin (~1/8") bar stock for backing. High amps and big rods will usually fully penetrate the backing plate and fill the grove quickly with few passes and no need for root pass or root cleanup. Functional as is, but when required for appearance, backing bar can be quickly removed and root gouged with CAC then one weld pass finishes the job.
Good luck, YMMV
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says...

should be 'spliced'

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Pintlar wrote:

I once saw a dc welder(bullet shaped vertical thing with motor and generator vertically) the leads were wrapped round the whole thing and someone started welding, the whole thing blew up and made a hole in the roof of the shed,
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amdx wrote:

And the FCC is going nuts wit all of the gruesome RFI complaints. Spark gap transmitters are almost 100 percent illegal now. "Almost"? if that was the only to transmit an SOS in a life-and death situation, then it is "just" barely acceptable (but do not do that again).
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Bullshit!
Hobbyists operate tesla coils and it is legal as long as you don't get too many neighbours complaining. They also operate in museums and at shows. Also some medical electrosurgery units that are still in use today use a spark gap.
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Shaun expounded in

I still have my Model-T 6V Ford ignition coil, that I bought on ebay (I was hoping then to interest my son in electronics). I haven't operated it in a little while ;-)
When I was young, I had made an HF coil using a paper towel cardboard roll form, and an outer coil of a dozen turns or so. There was a HV cap involved to cause it to resonate.
I'm not sure what the output freq was, but it was fun drawing sparks to your hands. Being HF, it would only tickle slightly.
I'd love to know what the lowest minimum frequency for human tolerance of HF HV arcs is.
I once knew a guy that claimed that he'd test TV HV power supplies by arcing the transformer +HV lead to his fingers (approx 15.7 kHz). I've never had the guts to try it.
Warren
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