Air arc questions

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I've bought an arcair K3000 off of ebay yesterday.  I won't be doing anything very heavy with it. Mostly using it to remove short intermittent welds attaching wear strips and gouging out the occassional crack rather than grinding. Any tips or things that I might need to know that I might not be aware of? What's the best method of starting the arc tap and pull back or strike the match? or does that matter? I plan on using 3/16" carbons what arc length should I hold? I'll be using a bobcat 250. I know that's not the best machine for the job but I won't be doing a lot of air arcing and a bobcat is what I have.
Reply:Carbon Arcing is a little bit different than welding. As long as you have a clean surface free of paint and have a good ground, using the right setting, the arc should be easy to start. I believe the mix is something like 7 inches from holder to work piece. I stick with about four inches or so. I mainly use the 3/8" rod though. Carbon arcing can be your best friend or be your worst enemy.AWS Certified Welding Inspector
Reply:Just scratch the carbon on the metal as it won't stick like a welding rod. You'll figure out what to do right quick as it isn't diffucult to operate. The stick-out on your carbon depends a lot on how much air pressure you have at the torch. I love the things for washing off welds. Faster and easier than a scarfing tip.
Reply:Your gonna like that one!I push the rod with the air blowing underneath it.  Turn the machine all the way up and have your way with it.  You will soon learn the control is great.  DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:pretty much gotta agree with everyone else, I do alot of air arcing, you will pick it up quick. Its kinda a crude process but you can get some very clean results, you will start using it instead of the grinder for lots of stuff. I love having it available. You can take anything apart that is welded together in short order. Its the anti-welder Yup
Reply:Be careful not to gouge straight in with it-causes like a carbon/copper coating on the base metal and that does not gouge off. you pretty much have to grind it or try to chip it off when that happens. Also happens when you try to gouge too deep.
Reply:Wear Ear Plugs!!....hmmm, thats odd. I did that in all caps and when I submitted, it went as shown. Wonder why.....Last edited by TEK; 04-27-2008 at 01:01 AM.Reason: curious about something
Reply:For proper effect, run the sound through a 1500 watt amplifier.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 never had to start the arc with it. Seems once it close enough it fires itself off. You might try 5/32 carbons as it will be easier on your machine.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:DCRP, Use amperage as recommended for the diameter you have. Hotter is not always better. Excessive amperage can make it hard when you 1st start because the travel speeds necessary to keep the arc going are higher. As you develop more skill, increase the amperage.One of the key things already mentioned is to keep the air between the rod and the workpiece. This keeps the molten out of the groove. Air with moisture can also cause problems. If the air holes on the electrode holder get clogged or deformed you can have difficulty.In addition to the ear plugs, a respirator is not a bad idea.Last edited by gaustin; 04-27-2008 at 09:29 PM.Reason: Add note about respiratorHave a nice dayhttp://www.weldingdata.com/
Reply:Still haven't received it yet. Not surprised because it's coming from Canada. 1/8, 5/32, 3/16" how should I size the electrode for the job? Diameter of the electrode about equall to the size of the weld I'm trying to remove or a bit smaller?
Reply:Originally Posted by tresiSnip.... how should I size the electrode for the job? Diameter of the electrode about equall to the size of the weld I'm trying to remove or a bit smaller?
Reply:Sizing the electrode depends on what you're trying to do ....  Are you trying to save both pieces of metal?  Assuming you're cutting out a weld? Then the smaller one is better; you only want to dig far enough to find the fusion line; without digging, a little more precise .....  If you only need to save one piece (say, cutting off old wear-strips), bigger is better, assuming you have the amps and air to do it.  Faster, and who cares if you dig too deep in the piece you're throwing away.  Plus, it's easier to remove the raised part of the weld on the piece you're keeping; much less grinding afterwards.  Cutting out cracks?  Deeper you need to cut, bigger the carbon ....   otherwise it takes more passes, then more grinding clean-up afterwards, plus with too small you get too much of a chance of the aforementioned carbon buildup, which is very difficult to remove .....Start by clamping the rod about halfway up; 6" above and 6" below the holder; then adjust as necessary .....you'll soon find what works best for you, with your machine and air supply.