Carbon Arc questions

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Ok I finally tried carbon arc cutting, which I know next to nothing about except that it's done with a stick welder.   I've been blessed with plasma, oxy-fuel and all sorts of rotating and reciprocating tools to cut metal with, so never had a reason to try carbon arc, but I thought what the heck, I'll experiment with it.   So, I got some 3/16 ArcAir copper-clad carbons and used them with the PowCon in stick mode on some 3/8" thick flat stock.   I don't know if I did it right, but they cut through the stock easy enough.  Cuts came out rough, but I will probly get better with some practice.   I didn't see how they could be used with air, as the rods don't appear to be hollow tubes, so I stuck a rod in the stick welding stinger, cranked up the machine and got to cutting.  After a few cuts, I found that pushing the rod forehand and using a little up and down 'sawing' motion  with the end of the rod seems to work better than just dragging the rod accross the metal like stick welding.What is the proper rod action when cutting with carbons?How does one go about using these with air?Also, I think on the first rod I musta had it in the stinger upside down.  I saw one end was bare for about the last inch, so, thinking it was kinda like a stick welding electrode, I put that end in the stinger.   It struck up and cut, but in a matter of just a few seconds, the whole rod heated up red, yellow, then almost white hot, like a glow stick, and the stinger was smoking and actually flamed up!  It was spectacular, and hot in the glove!   Figuring that was probly a mistake, on the next rod,  I put it in the other way with the bare end to the metal and it seemed to cut better that way, could be re-struck easier, didn't light up like a glow stick so much and the stinger didn't catch fire.Which end of the electrode is supposed to go in the stinger?Any other suggestions?Thanks for your help!Last edited by DesertRider33; 03-10-2008 at 12:24 AM.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:From what i've seen of carbon-air cutting, the 'stinger' also has air jets on it.  The arc heats/melts the metal, the air blows the molten puddle out of the way.I guess in a pinch, could put a metal tube coming off your air blow nozzle.  Strike the arc, use the air nozzle to blow the metal around.
Reply:google arcair gouging torches.   The electrode holder has an air connection.  The air blast comes out of orifices in the jaws of the electrode holder.  You need at least 80 psi and large volume.  You also need a large welding machine with a high duty cycle.
Reply:Desertrider33, the carbon arc can be used to make rough cuts, but is used mainly for gouging welds that I have seen. You can pick up a good new gouging lead for about $200 they aren't the cheapest things, but it sure saves you hours of miserable grinding and if you strive to perfect the gouging skills you can do some pretty amazing things with it. Making loud noises and throwing long distance sparks the whole time. Mine is an arcair K3000 and it looks kinda like this
Reply:Hmmm, ok, now that makes sense.   I thought maybe the rods had to be hollow so the air could shoot down the center of the rod or something.   I'll check out that Arcair torch next time I go to the welding supply.The welding machines I can use it with are a Bobcat 250NT, a PowCon 300SM or a Dialarc HF.   I'm most interested in using it on the Bobcat.   I have a 2-stage 175 psi compressor on the truck that puts out plenty of air so air shouldn't be a problem hopefully.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:If  .....you have a large ENOUGH machine, and learn how to air-arc properly , it is not so awful loud . You need to have a steady gouge, NOT where it goes  "blap, blap, blap !". It should sound more like SHHHHHHHHHHHHHH ! Use plenty of air ! with enough practice, a welder can gouge almost good enough and clean enough  that the gouged area does not have to be ground clean to then do an x-ray quality weld . I know , on submarines , i did hundreds of hours of air-arcing, with up to 1/2" carbons & 1000 amps. At Kaiser Steel ,i used up to 1200 amps , with a 5/8ths " carbons, on roundabouts for rotary kilns .[SIZE="5"Yardbird"
Reply:Before I got the proper lead, I used a blow gun and carbon rod.  With the proper holder, you can do some nice work burning old welds off.  250 amps is almost big enough for 1/4" carbon.  Like Roy Hodges said, 1,000 amps for a 1/2".  1/8 gouge rod will work around 150 to 200 amps.  I use 3/16" on the ranger 250.  It beats the heck out of using the torch especially if you are gouging crappy bird dung welds.Its worth the couple hundred bucks for the proper stinger.  I have seen them for $141.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:"What is the proper rod action when cutting with carbons?"Usually, a sweeping washing movement, with slag being blown away in the clearest direction possible.Mainly depends on access and the objective."How does one go about using these with air?"Position the torch so that the air jet has the best possible blast at the molten metal. Preferably with the air blast not blocked by the work, or the carbon itself. The air is controlled with a thumb valve."Which end of the electrode is supposed to go in the stinger?"For starting, the bare end toward the work. I usually clamp a long carbon in the center; lessens rod overheating, gives better control, and more air blast to the work. Again, depends on access; in tight quarters, snap the carbon to size, clamp it any way that works."...I thought maybe the rods had to be hollow so the air could shoot down the center of the rod or something...."  Some rods are hollow, but not for airflow, it's a theory about current flow. "Any other suggestions?"Compressor CFM is more important than peak PSI.Start looking for leathers! Good LuckBest carbons I ever used, were left over stock from the drive-in movie projector! Seriously
Reply:Thanks guys!Wow, Roy, that's some serious juice there!   I don't think I've even seen a machine that big before.   Sounds scary.David, so I should I stick with these 3/16" carbons to use with the Bobcat?  It's 100% @ 250 amps DC, if I remember right.   The compressor has it's own gas engine, so all the generator juice can go out to the electrode.I will start saving for a proper 'torch' for holding the carbons.  Denrep, I don't know what the cfm on the compressor is, but it runs multiple sanders at the same time continuously with no running out of air and the plasma cutter never lacks air with it either.  It fills the 30 gallon tank in very short time.   Thanks for the explanation on the rod action and correct way to clamp them and use them!   Yep, I got plenty of leathers .This is why it's good to be on the forum  .   Great information, thanks!MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:You are going to like it.  I have a 5 hp gas powered compressor on my truck and it will run the arc air all day long with 3/16.  So will the ranger 250.  Its not hard to do with a blow gun. Just don't use a safety (30 psi) blow gun.Watch where you aim it.  I wear earplugs.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Cool!  My welding instructor is gonna show us how to use the carbon arc in the next week or so! The process sounds great for removing old suspension brackets that were welded to the frame.
Reply:Cool! My welding instructor is gonna show how to use the carbon arc in the next  week or so! The process sounds great for removing suspension brackets that were welded to the frame.
Reply:I've used 3/16 carbons with an SA200 in a pinch though they were definitely all it wanted. They also come in 5/32 and 1/8 either of which would probably work well on the bobcat. Just like with welding electrodes you size them to the machine and the work. I've used a 1000 amp Miller, but not for gouging. Running gas shielded flux cored wire with it at 650 - 700 amps it will burn your eyes in seconds and if you stand too close your clothes will start to smoke. Bet it would make a heck of a fire gouging, heheh. Once you get the gouger down it works really well. It is also faster and cheaper than using an O/A scarfing tip and works like a dream on stainless and cast iron.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:You get a little time in with one of those and you will love it. So much faster than a lot of other methods at times and You can gouge out a weld and not even need a grinder to clean it up. One of the very useful tools for heavy equipment repair. One thing to remember is that you are throwing a lot of fire around around. Be careful you don't start any unwanted ones.
Reply:Choose your weapon!  Attachment 17698Last edited by denrep; 10-19-2010 at 11:25 PM.
Reply:Denrep, that's some thick carbon there!   What's the difference between the round and square?Thewelder, yes, I will watch out for brush fires.  God knows we don't need any more of them here in southern California.Jolly Roger, I may pick up some skinnier carbons too if the local weld shop has them.  When I got the 3/16 ones those were the smallest I saw on the shelf.Stickkid, from what I saw of it when I experimented the other day, I think enough juice with these things would remove about anything made of ferrous metal.   Maybe other metals too, don't know about that yet.David, that's good news .   I think the motor on my compressor is 10 hp, it's an old Kohler gas motor.   I'll try not to point the carbon at anyone I don't like.  MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I use the flat carbons quite often when I am putting bevels on piling. They take a lot of power but one pass and you can have the nicest bevel you have ever seen.
Reply:Polarity is important too, I think that you CAG with DC Rev, but, I may wrong. Its been awhile, but, you'll know if it's wrong. You'll get black smears on the metal if polarity is wrong.....KennyYeah, yeah, I know you are a weldor too. But, are you a good one?
Reply:The metal doesn't have to be ferrous. If it conducts electricity the Arc-Air will gouge it. It's a really handy tool.
Reply:I was using them in DCEP.   I dont recall seeing black smears.Flat carbons for beveling.  Works with all metals.  That was good information, thanks!MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33Denrep, that's some thick carbon there!   What's the difference between the round and square?
Reply:I picked up an air arc stinger yesterday. Hmmmhmmhmmwhooowhooowhooohaaahaaahaaa!  I'll start in with my sample pack of 3/16ths carbons soon. Too much going on to jump right into it yet. Glenn at the LWS says, "Now don't go cutting those trailers in half!" City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:I've read all the above posts about the arcair. I just bought a new K-2000 with 3/16 in carbon rod. I haven't used it yet. All I have is a Emglo 4gal, 1.5HP air compressor. In their literature, Thermodyne recommends 8 cfm @40psi to do intermittent gouging. I don't think that mine can do more than 5 or 6 cfm @40psi. My question is, has anyone done the small diameter gouging successfully with the small "nailgun" compressor. Although a new large capable compressor "only" costs another $440,  I don't have anymore room in my shop for a large, tall compressor. I'm assuming that these large compressors don't want to be set up outside, outside my shop. Am I wrong?  Any comments by experienced folks appreciated.Miller XMT304 w/22A Wire FeederLincoln Electric 3200HDHarris OxyAcetylene TorchesHyperTherm Powermax 45
Reply:I think your compressor is too small.  You can use 1/8" carbons and less air.  I use 80 PSI with a 5 hp gas (11 cfm) or 15 cfm electric one in my shop.  You will be able to gouge for about 30 seconds and wait for air. I did this one with 1/8" carbonhttp://weldingweb.com/vbb/showthread.php...hlight=arc+airDavid Last edited by David R; 02-21-2009 at 04:36 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:I bought an Arc-Air setup a couple of years ago.  Didn't like it, sold it on eBay.  I used to sell a "cutting/chamfering rod" when I was with a welding supply company.  Cronatron Welding Systems has what's called the #110.  Like Arc-air, you use DCEN.  Really "U"s out material for weld preparation.  Eutectic has one also.  I bought some cutting rods at my LWS, did not work like the #110's.Good Luck with your Arc-Air.What size of airarc torch you have will will effect how much air you'll need. Your air will last longer if you use a regulator rather than runnig it straight from the tank. There is no reason to get the larger torches/holder unless you need them. I got a k4000 set up becuase I got a real good deal on ebay. I would be jst as happy with a k2000 because like many of you i only have a 250 amp machine. The air arc torch is pushed rather than drug.  The ear plugs are not just for the noise cause it really isn't that bad, not like an air hammer or something. Wear the earplugs because if you get a hot one down your ear you will have no other problems at that moment.Tough as nails and damn near as smart
Reply:Are you saying that my 4 gal comp will only be able to go for 30 seconds? Any idea on recovery time.Is thirty seconds enough to blow out, say, 6 in. length of 3/16 fillet weld.  If that were the case, I could live with that.I'm trying to get an idea of how much time, effort and money is worth putting into this new compressor issue.  Finally. ifI do go for  a new larger one it,are there any compressors made to live outside?ThanksMiller XMT304 w/22A Wire FeederLincoln Electric 3200HDHarris OxyAcetylene TorchesHyperTherm Powermax 45
Reply:All I am saying is your compressor is too small.I do use a regulator set at 80 psi.  For smaller stuff I could go lower.David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Sure, portables stay out in trucks all the time! If you get an electric, maybe cover it in a proper fitted shed or cover, like a water heater. I had considered that option myself at one point.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:DONT  RUN IT DCEN!! You just need enough air to to move the removed metal. No reason to blow molten metal across the yard. always go downhill and leather up. I use the flat rod to gouge thicker metal. seems to handle it better when you are beveling out a crack. Long smooth enen strokes and dont try to hog out alot of material in one stroke. skim an 8th at a time and it will come out nice. always work away from you. if you dont you will be doin the fire dance in no time.Air vantage 500 on the 08' KWharris torchesl25 pro suitcasecomletely restored 1969 SA200 redfaceon my 08' duramaxPIMPN AINT EASY
Reply:yeah no kidding! make sure the air holes always trail the electrode.only thing worse than an ugly woman is an ugly weld