From the looks of it, it seems to be a welder with compressed air blown thru the center.

Is it an arc and compressed air?

Just wondering how these cutters work...

 

It's higher voltage than a welder, about 90 volts. There are actually two streams of air, a low pressure and a high pressure. The low pressure comes on as soon as you hit the trigger, and the pilot voltage from the power supply ionizes this air, actually making it conductive. Once the pilot arc is established, the main power switches on, along with the high pressure air. The current breaks the base metal into it's components and breaks the bond with surrounding metal, and the high pressure air blows it out as slag. The arc the machine produces is something like ten times the temperature of the surface of the sun, give or take a few degrees.

 

Kind of an advanced newfangled Air Arc machine! Those were fun to operate back in the 70's.

 

weren't they though eric?? none of the "kids" today believe me when i mention the air-arc rods. they look at my like i am on drugs.

 

I may just try to find a rod holder and see if I can crank enuf amps out of my welder to operate one. The unit I used had an air blast and used a standard carbon rod. I may have to fabricate a rod holder for something like that tho. Not real difficult. With an Air Arc I can pick a weld bead out of something if necessary. -Kind of handy to have but I have to use two hands to control it nowadays.

 

Eric - tried and failed ! I used a Lincoln 170T mig welder for the experiment. All I did was melt the end of my homemade plasma gun. I ended up buying a Miller 375... gross overkill for my needs but it works fantastic.

 

I have a good industrial Miller 225A AC/DC stick welder that may work for an air arc.

I also have been looking at using it as a power supply for a MIG since I have a good wire feed unit. Unfortunately a stick welder is a constant current machine and a MIG is a constant voltage machine (or maybe that is backwards). I have heard it will still "work" and since I have the head for free I might as well try. It will only cost me a roll of flux core. If that works well enuf I would hook up gas.

 

eric, your miller 225A stick should be more than enough for an air-arc gun. the graphite rods were still available a few years ago, the thing to find is going to be the air blast tip/ rod holder.

 

arc-air torches and gouging carbons are still available and sold at any well-stocked welding supply. A lincoln 225 stick machine is the bare minimum to try and arc gouging is really rough on a power supply. Plasma cutters use much higher voltages than a welder.
Typical open circuit voltage is in the 200-300 volt range. Actual cutting voltage is in the 100-200 volt range. conversely, a typical welder open circuit voltage is in the 60-90 volt range and weld volage drops way down anywhere from 15-50 volts depending on machine, process, arc length, etc. etc. A proper setup for a plasma transformer would essentially be 1:1 as the voltage and current are nearly identical to the input to a 230 volt welder( 230 volts/50 amps). Since I have 2 or 3 plasma torches laying around, I've seriously considered taking a junk welder I've got, wiring it up where the primary and secondary are reversed, putting the rectifier on what WAS the input, and using the output of my tig as it's input. This way the tig's current control would also be the plasma's output control. Haven't had the time to try it, but it should theoretically work. BTW, plasmas also have a way of starting the arc, and beginning the conversion to plasma. Ususally this is the same high-frequency setup as used in a TIG machine.

 

It'll "work" but not good enough to want to use it! (LOL). This is why there are special(expensive) feeders and adapters to do MIG off of constant current machines. You REALLY need CV to mig with. I'm in the other boat myself. I've got a good CC/CV power source and a box of parts that I'm trying to make into a viable feeder.

 

I have seen the carbon rods but not the holders in the local supply store. I figured I might have to fab the holder or even scrounge one from some surplus/salvage outfit.

Maybe having a CC power supply will make MIG a challenge instead of something a trained monkey can do...

 

at work we use air-arc rods everyday. Also the cnc plasma-table is really neat to watch. as for getting holders, try thermadyne arcair or praxair.

 

Oh, it'll make it a challenge alright
The torches are probably special order or might not be out on display. They are also VERY rebuildable, so I've seen a lot of places that stock enough parts to build one from scratch but not have a whole torch in stock. They don't sell enough of 'em to stock 'em sometimes. Even if they have them, you might have to ask.

 

If I don't find one used at some salvage place I will ask at the local shop. -Thanks!