Minimum Amps for Air Arc Gouging

[woodlandfarms]

Was looking into this for a project instead of trying to get the steel seperated with grinders and cut off wheels. All I have though is a AC/DC Lincoln Tombstone which is 225 AC and 180 (?) DC. And what kind of air is needed? I have a 40 gallon...

 

[Shield Arc]

You might get away with 1/8-inch rods. I think the smallest I've ever used was 1/4-inch.
I always liked 400 + amps, with couple hundred pounds of air, but I was always in a hurry!

Products

 

[Gary Fowler]

I don't think your Tombstone Lincoln's duty cycle will allow you much time to air arc, but then again neither will your air compressor. You need a lot of air volume to do that and not many home duty air compressors will get above 135 PSI. I don't think either of your machines are capable of doing arc gouging.

 

[woodlandfarms]

Thanks guys. I didn't know much about it so this all makes sense. Will head to Harbor for some cutoff wheels.

 

[stuckmotor]

I tried arc gouging with my AC Tombstone and an air gun hooked to a Harbor Freight compressor. The results were disappointing.

 

[yomax4]

The way the tomstone is built, You would burn out the heat selector by doing a wide open dead short. Rule of thumb..350+ amps to carbon arc with a machine that is not wired up like a tombstone.

 

[Arc weld]

Your machine is way too small and light duty for gouging. You can get lighter duty gouging torches that only need about 8 CFM and can run 1/8" gouging rods but gouging is really hard on a machine. I worked in a shop that did chromium carbide overlay inside pipe for the oil sands. They used flat carbons to gouge the hardfacing off when welding elbows together. Lincoln SAE 400's are one of the most heavy duty welders ever made and this shop had a couple sitting in the corner that were burn't up from gouging. You can see the cables jump when you strike an arc and can feel the current going through if you hold the cable while someone is gouging.

 

[Shield Arc]

I don't know what the cheapest plasma cutter that can scarf would cost. When taking out a weld I would much rather use a plasma than a carbon arc torch. Scarfing with a plasma reminds me of watching the surgery channel when they're doing laser surgery. Now if I wanted to hog off a bunch of iron I would rather use a carbon arc torch with the flat rods.

Here is a weld I took out with my plasma.

 

[Gary Fowler]

Before they had plasma torches and the like, we used oxyacetylene torches with a scarfing tip to remove old welds when we didn't have access to an arc gouger. Slow and hot, but it got the job done. Never used a plasma for gouging, only cutting, but it doesn't look like you have good depth control with it like you would with carbon arc or even scarfing tip on a torch.

 

[Shield Arc]

Oh it's a lot easier to control the depth with a carbon arc torch! With a plasma you control the depth with angle of the torch, or amperage.
I haven't used a scarfing tip on a torch in years.

 

[yomax4]

Plasma is very nice for removing old welds, Races off of shafts etc. you actually turn it down and yes it can be surgical. Don't have to get it red hot 1st and can go over it several times before it get too hot. Very nice. Plus you have the Aluminum, SIB, Cast and Stainless option as well. Try it.

 

[Gary Fowler]

I just haven't found the need for spending the money for a plasma. So far I haven't found anything that I couldn't remove with my oxy/fuel torch or grinder. If I did a lot of fabrication and repairing, it would be worth the $1000+ dollars for one, but today I just fix what breaks around the farm and no alloys here, just low grade carbon steel to deal with. 4.5 thru 9" Grinders take off most everything I need and the torch gets the rest.
By the way, I can take nuts off bolts, races off shafts with my torch and not worry about nicking the shaft with my oxy-acetylene torch.

 

[Shield Arc]

I just haven't found the need for spending the money for a plasma.

I agree, for the majority of us here a plasma is just a luxury! In a fab shop, sure. I bought mine to go along with my CNC table. I retired early because of health reasons, I thought I wanted to get into metal art to pass the time, about a year after I bought the table steel prices went through the roof. I couldn't sell the metal art for what the steel cost me. So now everything sets and collects dust.

 

[yomax4]

No question about it. Plasma is a luxury. Much like an air Impact compared to a crescent wrench. I've burned up a lot of cutoff wheels and oxy fuel as well..Still do.

 

[drizler]

Just get a cheap oxy propane cutting rig from HF. I don't weld with mine but when something big comes along I break out the torch. Comes in real handy when you have rusty nuts n bolts to deal with as well.

 

[woodlandfarms]

I have a nice victor setup but I do not have a gouging tip. Then again, I don't have much experience or skill with it either

 

[chriswheeler]

I somewhat agree with all here. I have the smaller ArcAir K2000 that I use every once and awhile with my small welder at home My welder is a Lincoln Square wave 175 tig. The K2000 uses much less air than the standard K4000 and can be used on a smaller compressor, 2 air ports in the K2000 where there are 4 in the K4000. Think it runs on 6 cfm @50 lbs. That said, you still need the amps or smaller electrodes. I run 5/32" and can get about 3-4" of cut before I'll stop and let both rigs cool off for half hour or more. Air arc can be hard on a welder this small, and I'll only resort to this for some reason like restricted access stops me from using a grinder. This is the only reason I'd like to have a older engine driven welder sitting around here. ArcAir starts working better @250 amps+, and much better the more amps you can pour into it with larger electrodes.
Chris

 

[Shield Arc]

My days of hogging out iron are long gone! I plugged two of the holes up in my carbon arc torch.

 

[chriswheeler]

Think the K4000 has larger dia. holes as well. If I had a K4000 I'd plug off a couple as well. Being retired, never in a hurry, not enough amps to run one to it's full potential, a K2000 is plenty. Smaller ones are sure harder to come by than the larger ones. One thing that should have been mentioned above is the " duty cycle " on any small welder that runs a arcair should be cut in half. Example, if you have a 20% duty cycle at full amps, cut that in half to
10%. Arcair on a small welder will toast it fast if you exceed that, it just isn't made for that type of a load. Still have the burn scars from running the big ones.
Chris

 

[Shield Arc]

One time I got elected to arc out some spacer bars in an 18-inch x 18-inch x 16-inch deep steel box. Only one side open. Talk about eating sparks for a couple hours.

The box looked just like this one in the picture.