An idea for $.02 LiftArc for HF TIG

rashid.karimov 20 years ago

Being kind of tired of electrode sticking when trying to scratch-arc-start, how about adding say 5-20 Ohm wirewound high-wattage (nichrome) resistor in series with either electrode, to get tungsten hot and arc start and then shorting the resistor ?

Assuming working voltage of 40V, 20Ohm would limit current to 2A - which should be enough to get tungsten hot w/o sticking and initiate the arc and this is where you'd release the foot swith and eleminate in-series resistance ...

SPST momentary switch rated for high amperage ?

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Ipeak 20 years ago

Interesting idea, please let me know if you figure this out, it could really be helpful.

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rashid.karimov 20 years ago

I am looking to get 200A relay. Interrupting/initiating 100A current flow is not a trivial task - mostly in terms of wear and tear on the contacts.

Also, having a relay do that means one can mount a microswitch onto the torch.

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Ignoramus21303 20 years ago

That relay would only need to initiate the current, not to interrupt it. Much easier on the relay in a welding circuit. You can buy a contactor like this for $10-15 on ebay.

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I bought two similar ones for $9.99 a while ago.

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john jacob 20 years ago

Car starter relays are 12 volt coil, and handle high amps. Although, the way I do it is tape a small micro switch to the torch, that operates the start circuit of the tig welder.

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