TIG to Plasma Conversion?

[Jack(IAT)]

Hello, this may sound like a really dumb question, but can an old TIG welder be converted into a plasma cutting unit? I have an old Miller TIG 250 here that only works in DC. From what I have read, a plasma cutter is just a DC TIG with a different torch. I really don't want to throw away this old welder and figured it would save me $2k to just convert it to a plasma cutter instead. Could this be as easy as just getting a plasma cutter torch/cable and integrate it into my own TIG with a built-in air line? Can or has this been done? Am I way off base here? I'm new... love the site! Thanks in advance for any help.

Jack

[Mat-C]

No direct answers, but I want to do the same thing
From what I have found so far:
* Plasma is also DC, electrode negative.
* The starting circuit may be different.
* The voltage/current source is probably similar to tig (plasma = const current, tig = drooping const current).

The torch looks straight forward... swirl ring, electrode, shroud and that's about it. Apply dry air and off you go. My concern is more the starting and voltage/current required. I'm pretty good with electronics so I could add diodes and constant current/voltage circuits but rebuilding a transformer gets tricky.

Anyone know a bit more about plasma voltage/current supplies?

[morehelium]

Short answer is no. At least not easily.

The main problem is output voltage. Plasma torches operate at around 100 volts as the higher voltage is needed to ionize a pressurized high flowrate airstream. Tig power supplies usually operate between 20 and 40 volts.

It might be possible to modify the transformer but probably more work than its worth.