Carbon arc gouging questions

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Hi.. While checking Thermal Arc's website for specs on their TIG machines, as I'm planning to buy an AC/DC inverter TIG in the near future, I ran accross an interesting feature of the Arc Master 300 machine... carbon arc gouging.   I was initially looking at buying the Arc Master 200 and planning to buy a plasma cutter at some point down the road and when I saw that the 300 can do both TIG and carbon arc, as well as MIG and stick, whereas the 200 machine is only for TIG and stick, I thought.. maybe I should get the 300 machine for its cutting capability instead of the 200 and the plasma??I know next to nothing about carbon arc cutting so I'm wondering is it a good process to cut with?   Can it make smooth cuts like a plasma or is it rough like an oxy/acetalyne torch?  What thickness and types of metal is the carbon arc process used for?   Is it more expensive to run than a plasma?   Does the process use alot of current input or is it about like a stick welder?  The 'torch' for the carbon arc looks like it doesn't cost too much, doesnt look much different than a stick electrode holder.. is there any truth to that?I only have 30 amps of 220 single phase available to run either machine, so I would never be able to use the extra 100 amps output of the 300 machine, but the carbon arc and MIG capabilities might make it worth buying instead of the 200.   I should be able to use most of the 200 machine's output, maybe 175 amps before breaker trips.   It would be nice to have the bigger machine for some time in the future  if I end up in a place with more power available and I usually buy the biggest machine I can afford even if I can't use all of it.     I dont want to waste money though either, so I'm asking my questions now before I spend it...Another consideration is I might be able to use the 300 machine as a power supply for one of the extra Cobramatic feeders and torches I have here, IF the Cobramatic can run on a constant-current power supply (I've only used them with constant-voltage before).   The MIG capability of the 300 machine isn't too important, as I use a PowCon MIG supply to run one of the Cobramatics with, but it could be a little extra icing on the 300's cake that could sway me away from the 200 since I could then make more use of the extra equipment I have hanging around here.   This is only if the carbon-arc cutting process is a suitable substitute for plasma, as I dont think I can afford the 300 machine AND a plasma machine...I dont know the pricing on the 300 machine.  Air Gas quoted me about $2400 for the 200 and I dont know if that was for the bare machine or if that included the torch and everything else.   Another shop quoted me $2900 and again, I dont know if that was just the machine or the whole setup.  I was figuring on spending about $1000 on the plasma cutter and a guy at one of the other shops thought the 300 machine would probably run about $1000 more than the 200 machine but he wasn't sure.  Sounds like maybe I would spend close to the same money for either the 300 machine, or the 200 plus the plasma.I intend to use the TIG for steel up to 1/4" thick max, usually more like 1/8 or less though, and probably not very thick on the aluminum either cause I dont think I will have enough amps to do aluminum thicker than maybe 3/16", if that, if my breaker only allows the machine to hit 175 amps out.   Going by the specs for both machines on Thermal Arc's website, my calculations indicate that at 20% duty cycle I would hit 30 amps in at about 160 out, so if it was only for a short period of time, maybe I could get 175 out of it.  Is that enough to AC TIG aluminum with?  Anyone have any thoughts on this??Thanks for all replies and any advice you wish to give!
Reply:Carbon arc gouging or air arcing requires a healthy supply of compressed air. I'm guessing at least a 10 HP compressor,someone correct me if I'm wrong. It will cut almost any metal that will conduct electricity. It usually doesn't cut very pretty. It is normally used to gouge out cracks in very thick metal so it can be welded up hopefully as strong as original or to remove weld to take a welded item apart. Maybe someone else will chime in here to give their knowledge/opinions.  I've used it a lot over the years,but not fond of it due to the fact it is extremely noisy and blows sparks and globs of molten slag EVERYWHERE!!!!It is my last option for removing metal.                         MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:Thanks for your reply!   "It usually doesn't cut very pretty" ... "not fond of it due to the fact it is extremely noisy and blows sparks and globs of molten slag EVERYWHERE!!!!It is my last option for removing metal."I was hoping that wasnt the case...So it looks like carbon arc wouldn't be a good substitute for the smooth clean cuts of a plasma machine...  Guess it looks like I'll probly go with the original plan of the 200 TIG machine and seperate plasma cutter.  Thanks for your advice!Last edited by DesertRider33; 10-22-2006 at 11:03 PM.
Reply:Depending on rod diameter the amperage varies, Larger diameter electrodes such as 3/8 require around 500 amps. So if you are going to loose 100 amps right out of the gate I wouldn't air arc with it because you would more than likely have to use a 1/8 electrode. And as stated above Mla2ofus has described the process so if you want the cutting characteristics of plasma it won't happen. I would check with an electrician as you might be able to install a larger breaker depending on how many amp service you have.
Reply:So it looks like carbon arc wouldn't be a good substitute for the smooth clean cuts of a plasma machine...  Guess it looks like I'll probly go with the original plan of the 200 TIG machine and seperate plasma cutter.  Thanks for your advice![/QUOTE]When I carbon arc I use a 3/8 flat rod at 350 amps @ 120 psi.  Not a good cut, but it can cut thick stuff unlike a plasma cutter.
Reply:Thanks for the additional replies!It would be great to get a 50 or 60 amp circuit in there.  I could use the full capacity of both of the machines I have now and that should be enough to run whichever TIG and plasma machines I decide on that are in my price range.  I have an oxy/acetalyne torch for rough cutting thicker metal than a plasma in my price range can cut so I should be ok without the carbon arc.  I dont usually cut anything thicker than 1/4" and I think 3/8 is the thickest I've had occasion to work with so far.Thanks again!
Reply:I don't have any experience with plasma, but I have good results with oxy-acetalyne. It takes some practice to cut evenly, but if you can keep your hand steady and closely follow a soapstone mark, It does a nice enough job for me. I've cut 1" plate with a mechanically driven o/a torch, it looks almost machined. You have to know what to set your gas pressures at and have a clean tip. Not to downplay plasma, I've heard nothing but good about it. Another thing is you don't need shop air to cut with o/a, you'll need it with carbon and plasma. And yes, I have used carbon in the past, not the tidiest cut but it's been around forever and it works. Good luck!If you don't have the time to do it right, then you definitely don't have the time to do it over.
Reply:I think your original plan was the best for your situation.  If you have a O/A setup and a plasma you should be set.  You should be able to cut whatever you need.  If you got a steady hand you can get just as good of a cut as plasma with the O/A.  Plasma will be nice for SS and aluminum though.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:Thanks for your insights!
Reply:If you use guides when you run your acetylene torch, it will  make an almost smooth cut.
Reply:a waterjet machine will do all that and more..and it dont care what its cutting..granite..stainless..aluminum..your hand..dont matterand in the long run for less$$$$...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Zapster, can you tell me more about these water jet machines?  I have heard of the technology but know very little about it.   I've not seen any for sale at the local or online welding supply outfits so I'm thinking maybe this is more for industrial applications?Thanks!
Reply:Water jet = MONEY$$$.  You also need to know CNC to use one.  It's just a table with a water jet nozzle.  You program the movements set a plate on it.  It controls the cutter head and cuts the shape you programmed.  It's not for the small volume user.
Reply:Here is some info on the CAC setup. It needs about 100 amps per 1/16" of electrode and about 70-90 psi for air. It's loud and hot. Very good for gouging out welds, but not nice clean cuts. Just my .02. HenryA bad welder makes a good grinderA grinder and paint makes a welder that ain't!If you can't put a good weld on it, put alot of weld on it!