arc gouging vs torch cutting, new project

admin

HI im mason,i just posted some pics of a project i finished up in the photo section.my question is, ive never done arc gouging.  so with that said i have a demo project to do on 12in. sch. 40 pipe.  about 200 ft of it with all kinds of elbows and tees ect. problem is,  the pipe is old and kinda rotted/ rusted out inside. making it hard to torch cut.dont cut very well, you have to go over your cut 2 or 3 times to get through it, do to the junk inside.would it be faster to arc gouge the piping out.   dont need strait cuts, just need it out the way to put new piping in.here is a pic of the machine i have.   not sure what else i need.  gouge stinger and air compresser.  thats about all i know about it.im a 6G certified welder Attached Images
Reply:In my opinion, you should stick to the torch. It's a pain in the pants for sure, but arc gouging I believe, would take longer with a similar result, and require more equipment. I've never tried cutting out old pipe with a an air-arc, but have demo'd miles of old pipe with a torch, and gouged a grand canyon of steel with an air-arc. You need 100lbs/sq in of constant air pressure and a lot of amps behind it. It is extremely noisy, messy, and chances are you are still going to be taking 2-3 stabs at your cuts.Beautiful job on what you are pulling in, btw
Reply:For doing what you are, I would use my 3 foot torch with a big old demo tip in it, you can cut a window in the pipe if you cant get all the way around it, and a torch wont make you go deaf either. Each one has there uses, but this is not the job for an Arcair torch.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:awesome guys! thanks for the info.   never done gouging.  could have wasted lots of time and cash setting it up for less resaults
Reply:For 12" sch 40, if you are in a safe area(not around combustibles or in a refinery unit, ect.) I'd rent a big diesel drive compressor and a 400 amp welder and go for it. Should take maybe four hours to arc gouge it down to manageable sizes.O/A torching all that old crap is a lesson in patience on a good day.Don't forget your leathers and ear plugs!
Reply:I would run oxy/propane. It works much better on rust, than acetylene."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:what about plasma unit? i would think a hypertherm 45 would be adaquate and wouldn't use any more power than the inverter welder shown.
Reply:can somebody explain a little more about what ACA wouldnt work? I know enough about it to be dangerous and have done it a hand full of times but i always want to learn more. I would think PAC would be a good choice if you have the funds to do it.speedway series 125 flux core welder
Reply:Carbon-arc gouging, as the name implies, is meant for removing surface layers of metal (usually old welds) and not for cutting. It is not a clean or efficient process for cutting through metal. Gouging also requires a fairly powerful air compressor, adding to the equipment you have to lug around.The reason that rusty metal is hard to cut is that the oxides (rust) melt at a lower temperature than the steel. The molten oxides coat the metal and make it hard to start the cut. Then, after the cut goes through, the oxides run back into the kerf and "glue" the pieces back together, making them hard to separate.Stick-man, I'd be interested to know why O/P is better than O/A for rusty metal. I've got an O/P torch somewhere, I'll have to try it out.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:imvho torch it. you say you're not very good with a torch? this is where you get some practice without screwing anything up. gouging is very loud plus not very fast production wise plus it really sends the molten metal flying.i.u.o.e. # 15queens, ny and sunny fla
Reply:Beat the scale off of it and torch it...... Do not be gentile.Miller Big 40GMiller HF-251 D High FreqVictor OA Lincoln 135 MigMK 3A CobramaticBridgeport J HeadCronatron OxylanceRadnor ACAG TorchWeldcraft TIG Torches1 blown knee and two 5 Gallon pails away from being a hero.
Reply:Originally Posted by Silicon-basedCarbon-arc gouging, as the name implies, is meant for removing surface layers of metal (usually old welds) and not for cutting. It is not a clean or efficient process for cutting through metal. Gouging also requires a fairly powerful air compressor, adding to the equipment you have to lug around.The reason that rusty metal is hard to cut is that the oxides (rust) melt at a lower temperature than the steel. The molten oxides coat the metal and make it hard to start the cut. Then, after the cut goes through, the oxides run back into the kerf and "glue" the pieces back together, making them hard to separate.Stick-man, I'd be interested to know why O/P is better than O/A for rusty metal. I've got an O/P torch somewhere, I'll have to try it out.John
Reply:oxy/fuel with a big tip. If the rust build-up insude the pipe is really bad after you pierce the pipe as your cutting move the torch head with a slight side to side weave. I do not think that little machine in the picture would live very long if used for gouging.
Reply:Originally Posted by Silicon-basedStick-man, I'd be interested to know why O/P is better than O/A for rusty metal. I've got an O/P torch somewhere, I'll have to try it out.John
Reply:So, you're a 6G Certified welder, yet, you're not sure how to cut material on a demo job? How does that make you feel? I'd be ashamed to even post such a question on a welding board while simultaneously claiming a "big dog" cert like that. 6G would suggest an above average familiarity with pipe/tube right? Just sayin...And, yes, I am an just another flipping a$$hole welder.E.AWS D1.1 Certified SMAW 3G Unlimited, Open Root                             FCAW-G 3G Unlimited, w/BackerCellular Tower Reinforcement Welding on the frozen tundra of the greater Mid-West
Reply:Yah, i kinda wonderd. I'm far from gods gift to welding, but cutting rusty/scaled material ain't a hard concept. Sorry if im a DbagLast edited by Cape Cod Gary; 01-21-2013 at 06:52 PM.Miller Big 40GMiller HF-251 D High FreqVictor OA Lincoln 135 MigMK 3A CobramaticBridgeport J HeadCronatron OxylanceRadnor ACAG TorchWeldcraft TIG Torches1 blown knee and two 5 Gallon pails away from being a hero.
Reply:Originally Posted by Welding_SwedeSo, you're a 6G Certified welder, yet, you're not sure how to cut material on a demo job? How does that make you feel? I'd be ashamed to even post such a question on a welding board while simultaneously claiming a "big dog" cert like that. 6G would suggest an above average familiarity with pipe/tube right? Just sayin...And, yes, I am an just another flipping a$$hole welder.E.
Reply:Cutting rusty pipe is long way from welding do they teach it in school. To the op torch will work you can beat off the loose rust to help with cutting. Also plasma works if you can get a good groundMillermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Originally Posted by farmshopCutting rusty pipe is long way from welding do they teach it in school. To the op torch will work you can beat off the loose rust to help with cutting. Also plasma works if you can get a good ground
Reply:I've had plenty of demo jobs in plants and buildings where we were adding an addition. I know exactlly what you are going thru. Rust is terrible to cut (if that's what you call it) thru. My suggestion would be to grab a huge demo tip and crank the heat sky high. Just melt the Hell out of it and let her drop. That's about the best you can do. Gouging would make you go def in a small room and it be a pain to control all the fire. I really don't see where it would save you enough time. One other thought could be a gas powered chop saw. We used to use one to slice roof/floor decking. The blades will bankrupt ya but I think it might be faster. Again, containing the fire is going to be Hell. I sure hope I helped. Thanks for reading!
Reply:The reason that rusty metal is hard to cut is that the oxides (rust) melt at a lower temperature than the steel. The molten oxides coat the metal and make it hard to start the cut. Then, after the cut goes through, the oxides run back into the kerf and "glue" the pieces back together, making them hard to separate. . . .
Reply:There are old threads where Jim from hypertherm and other members discussed oa vs plasma. Plasma will work if you have one. Consumables last a long time as long as you don't get crazyMillermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Hey Mason,At the same time, your machine may not be recommended for arc gouging.  I can't tell what you have, but my Squarewave 275 is NOT recommended for gouging by Lincoln, While a Synchro by Miller is, as far as I've seen.Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:Originally Posted by dubl_tHey Mason,At the same time, your machine may not be recommended for arc gouging.  I can't tell what you have, but my Squarewave 275 is NOT recommended for gouging by Lincoln, While a Synchro by Miller is, as far as I've seen.
Reply:Originally Posted by 7A749Yeah, analog transformer, DC engine drives or DC generators are best for CAC.The deal is the heavy, sudden load CAC puts on a machines that tends to be hard on solid state electronics. Now, the big inverters can run CAC & do it quite well as a matter of fact, but even the 400+ amp inverters will wear out a lot faster than under normal use if you are doing CAC with them on a regular basis.I'm with the majority on this. Oxy Fuel is the way to go. CAC needs a good ground & it don't like heavy rust. Not to mention 300 amps is kinda baseline for any kind of efficient operation. 400+ is by far preferred.IMHO of courseok, my bad. i'm thinking you meant carbon arc gouging? i'm on vacation and was up late last nite.i.u.o.e. # 15queens, ny and sunny fla
Reply:Originally Posted by 7A749Yeah, analog transformer, DC engine drives or DC generators are best for CAC.The deal is the heavy, sudden load CAC puts on a machines that tends to be hard on solid state electronics.
Reply:Originally Posted by JimboSliceOne other thought could be a gas powered chop saw. We used to use one to slice roof/floor decking. The blades will bankrupt ya but I think it might be faster.
Reply:Originally Posted by DSWDown side  to the saw is the carbon monoxide fumes in a closed room. I've done quite a bit of interior floor cutting with gas saws and ventilation is key.
Reply:The air saw adds high pressure pneumatic exhaust to help ventilate the workspace too.
Reply:The saw cutting of 200' of installed 12" pipe would be one noisy miserable dangerous blade-pinching dust-generating task. I can hardly imagine an installation that would have enough clearance to pass the saw all the way around the pipe.
Reply:Originally Posted by denrepThe saw cutting of 200' of installed 12" pipe would be one noisy miserable dangerous blade-pinching dust-generating task. I can hardly imagine an installation that would have enough clearance to pass the saw all the way around the pipe.
Reply:Originally Posted by denrepThe saw cutting of 200' of installed 12" pipe would be one noisy miserable dangerous blade-pinching dust-generating task. I can hardly imagine an installation that would have enough clearance to pass the saw all the way around the pipe.