Master,
First off, CAC is not a "Joining Process" subject to NDE. So...there is no grinding, torch cutting or gouging certification. Its noise and fire hazard far exceeds the individual welders work area.
Carbon air arc cutting (gouging) requires specialised equipment, is difficult to contain the sparks, and have you tried CAC in a confined space in the overhead position yet?
Try this excersise. Weld 2 pieces of 6 X 6 X 1/2" plate at 90 degrees to each other in a "T" configuration to the bottom side of your welding table with 5/16" fillet welds and D1.1 acceptable fusion at the root, all the way around. Then crawl back under there and gouge them off WITH OUT using a grinder or hammer. Then you will know why welders despise Air Arc.
That being said, CAC IS used on jobs with detailed procedures in place for it's use in many repair specifications, ie. minimum preheat and other preparatory measures. I am a big fan of the process. I also have a scar only my wife and a Urologist will ever see! (talk about having some explaining to do with the Wifey when I came home with THAT burn).
It does have it's place in the industry due to its efficiancy at removing LARGE amounts of material
CAC is also a victim of the old addage "Your reputation preceeds you"! Many have heard the horror stories before ever operating or even seeing the tool!
I like your Instructor though we've never met, simply due to the fact he is promoting the process.
Given the choice, a large % of welders will do all they can to avoid it.
It depends on how much metal needs to be removed and why it needs to be removed.
If your objective is to remove 49" of linear incomplete fusion 1" deep on a 2G downcomer on a boiler in Farmington, NM (hypothetically speaking of course) then let's arc gouge. If we are trying to find a cluster of porosity 3/8" below the surface on Reactor Coolant Piping then we should use the grinder.
It's easier to see the defect with a grinder. And you want to FIND the defect before repairing it and getting it NDE'd again.
If you are trying to completely remove a partial pen weld (56") on a cylinder lug that was mistakenly welded before it was properly aligned in Raleigh, NC last week (again, hypothetically speaking) then CAC would be the way to spend last Saturday.
If you needed to cut off a 1/2" thick temporary lifting attachment 6" long a torch and grinder is probably the best choice.
It also depends on where you are at and if you have air service readily available and a power source that is capable of the abuse that CAC will inflict on the welding machines. Sometimes it is more work to get set up for CAC than it is worth.
Sometimes it is the only way to go.
Superflux is right, most welders DO NOT want to CAC unless they have to.
The names have been changed to protect the innocent. :-)
Master,
First, welcome to the AWS Welding Forum. Hope you find much here to help you along in your choice of a profession. Lots of great people with lots of knowledge here. Just keep that good learning attitude.
Super & SWS have given stated some very good points. The key thing to remember is that there is a place and a time for every process, that means processes for joining and processes for taking apart or repairing. Rather grinding, torching, or air-arcing is the process chosen, each has it's advantages and disadvantages. Some are better suited for certain jobs than others.
While I agree there are a lot of welders who prefer not to use CAC, in my own opinion, it is because they have not been properly trained in it's use or somehow had a bad experience with it. If your instructor teaches you right, and it sounds like he has you headed right, he will show the difference between different sizes and shapes of electrodes and how to set the amperage on the machine for the proper use of the different sizes. When you learn to skim a 1/16" layer of material away from a weld needing to find that porosity just below the surface, and get it down to sound material before rewelding, because you chose 1/4" electrodes at a lower amperage instead of 3/8" electrodes with the machine cranked all the way up to 600 amps, you can be proud of your skills taught by an instructor who cared enough to train you to standards that few ever get or take the chance to learn.
Keep learning and asking questions. You'll go far.
Have a Great Day, Brent
Become proficient at it! It is a very valuable skill in my line of work. We also use the plasma to gouge with in the shop and if you have this opportunity learn it as well. Just remember to always protect yourself, your work area and others because of the noise and flying sparks. I wear ear plugs and muffs when I gouge. A leather hood is also a good investment if you think you will be doing a lot of CAC. As stated above there is a use for every process so it’s a really good idea to be as well rounded as possible in this field.
Hello everyone, Ive been wanting to get into arc gouging for some time now. Can someone please recommend:
1.What kind of machine I should be looking at-mobile of stationary?
2.What amp range?
3.A manufacturer of arc gouging equipment?
Thanks
Austin,
You need to begin by asking yourself what type of work you want to do with it after you learn how to use it. Will you be wanting to do jobs for people repairing equipment that they can't bring to you? How heavy of metal do you expect to need to remove?
Either engine driven portable units or electric shop units are fine to power the arc. It only depends upon what you need to do.
Amperage can run anywhere from 300-600 amps commonly. Again, depends upon what you are doing and which electrode you feel will handle it best. 1/4" to 3/8" round electrodes are the most common, in my experience. 3/16" is available for smaller jobs, lower amperage machines.
Any welding supply should carry equipment such as the torch and parts.
One thing you didn't ask was the air source. Any compressor able to handle 15 cfm is good for moderately continual use, few breaks. 20 cfm and up is better for heavy continual usage.
Have a Great Day, Brent
Brent, thanks for your response. Most of where I wish I could use it has been in the field for demo work. So and engine driven machine would be nice. What is your recommendation on one for the field. I would also like one for the shop for going thru multiple pieces of the same rough lengths fast. If I have a shop one do I only have 200 mp service-is that sufficient?
I do have both mobile and stationary compressed air.
Thanks again Brent. Hope you had a good Thanksgiving.
Master0428
I agree with you. There should be some sort of minimum qualification achieved for performing Air Carbon Arc Gouging, both for the welder and the equipment.
Joe Kane
Hey Joe
AWS EG2.0 Curriculum Guide for Entry Level Welders contains Air Carbon Arc componants.
KEY INDICATOR 1: Performs safety inspections of manual CAC-A equipment and accessories.
KEY INDICATOR 2: Makes minor external repairs to manual CAC-A equipment and accessories.
KEY INDICATOR 3: Sets up for manual CAC-A scarfing and gouging operations on carbon steel.
KEY INDICATOR 4: Operates manual CAC-A equipment on carbon steel.
KEY INDICATOR 5: Performs scarfing and gouging operations to remove base and weld metal, in the
flat and horizontal positions, on carbon steel.
With the some basic criteria for performance:
EVALUATION CRITERIA: The trainee produces sound manual CAC-A scarfs as well as round and
rectangular gouges, in the flat and horizontal positions, on carbon steel. The trainee prepares base
metal for both initial and repair welding. The trainee removes both weld reinforcement and all weld metal,
and the base metal is salvaged for further use. During and after each operation, scarfed and gouged surfaces
are visually examined by the welder, and accepted by the instructor on a routine basis.
While it's not a code style performance qualification I think it's pretty useful.
This is a good example of the value of adopting the SENSE curriculum.. Many/most schools and training facilities cover what is in the SENSE curriculum anyhow.. Those that don't can usually easily comply with just a minor tweak.
There are now 4 states that have or are planning to systemically adopt SENSE... This may go a long way to help industry recognize some of the value of SENSE that has been so long overlooked.
Joe,
With all due respect should that not be "There should be some sort of minimum qualification achieved for performing Air Carbon Arc Gouging, both for the welder and the equipment."
I have never "got" anything but I "get" a lot of things.
And I do agree with you. There should be some kind of "ability test" for lack of better words, for use in code situations. Trust me when I say that I have seen some stuff really screwed up after someone who was not trained, let alone informed, tried to git-r-dun.
John
John
I can't believe I wrote that "Got". My blood sugar must have been high! Thanks for pointing it out
Nobody's perfect Joe!!! :)
Respectfully,
Henry
In my industry we either use a grinder or occasionally a plasma cutter. We don't CAC because of the mess and we don't have the equipement.
Its loud, messy and it sucks. But there are applications for it as have been posted. But one thing never use it for is to cut the hinges off a door of a '57 Chevy that a guy is trying to restore. Because if by chance it gets out of hand a bit and slices a 3 inch long slot in the skin then that guy might get a little p***ed with you. But with several other welding students around watching the fireworks and him being the only body shop student, then whats he gonna do.
Needless to say don't try this at home. :-)
I think it's awesome and love it. I've only been called out on a job to do it once ever though. Most customers have never even heard of it though.
The qualification should be that the person doing the Air Arcing should be the one to do any required welding after words. Very good incentive to use care and a grinder.
A carbon arc is invaluable when it comes to repair work, like cutting out cracks in heavy plate and castings. Or just plain weld removal if your disecting something.
I cant count how many times ive repaired a crack or broken part with the aid of cac, when there is no way you could fit a grinder.
Once you get good at it you can cut huge v grooves in heavy material with ease.
Its a very valuable skill. I have gouged bolts out of holes and nuts off of studs (2-1/2'' stud bolts) on heat exchanges. Demo-ed heavy wall stainless and gouged end caps off of vessels after hydro. Its the fastest way to remove a lot of metal. I will say that gouging in tight qaurters or on things like H-beams were it's hard to get out of the way, does suck. But grinding for hours on end sucks too. Get good at it, it will come in handy one day.
in our shop we use it to prepare many joints and use it all the time for repairs, it is one of the finer skills of the trade but indispensible.
any time a gouger can be used safely in our shop it is.
as it is extensivley taught with our certification process here in bc canada that you are qualified to carbon arc gouge.
it is often part of of our wps and pqr programs.
it is often done with machines that are adjusted too high or too low and it makes it difficult to get a clean gouge, equipment really does matter when carbon arc gouging, the time to set up your equipment as close to perfect as you can get will save way more time in not having to grind.
i am a great fan of air arcing, you do have to make sure your covered up though or you do get the opportunity to explain some nasty burns in or on parts of your body that are not designed to be exposed to high heat.
Its a fantastic tool used to punish the people around you. IT has its uses but it has its downsides too.
Is grinding for welders who cannot Air-Arc? More likely for welders who cant weld.....:)
Steve.E
Well said,"More likely for welders who cant weld....." : ) I have been watching the thread and there are a lot of good posts. But you hit the OP's opening statement on the nose.
It is a valuable tool when necessary, prepping the back side of a CJP when Backing is not an option, dissecting assemblies, repair, and even when the draftsman messes up and calls for a 7/16" fillet all around when the Contract actually calls for CJP with U.T. and when you find out, the shop has already done 54 Wide Flange Columns with 1 1/2" Base plates that now need to have Bevels worked to sound weld so as to allow for the weld out as specified.
Funny how all the best welders suddenly dummy-up and no one knows how to air-arc. LoL
Marshall
I love the air arc. It is one of the most useful tools available for a metal worker.
I will always grab it before a grinder if it is suitable for the job at hand.
Some weld tests incorporate air arc use, like the seismic restricted plate test.
I would like to see some kind of qualification for its use. It is not hard to operate after minimal training for a decent welder, but some welders haven't had that minimal training. Not knowing better they may leave carbon and oxidized metal in a groove and then commence to back-welding.
It's always amazed me just how many welders don't know anything about air arc. I've seen guys use a torch and gouging tip, which works, but not nearly as well as air arc. And I've heard a lot of B$ about how air arc blows carbon into the steel. It's quite easy to use and is invaluable for accurately removing large amounts of material quickly. You can cut pretty much any metal like brass or stainless steel, for example. Try that with a torch. Yes, it has some charactistics that limit it's use. Can you come up with a process that doesn't?
Tom
Like wrench tech said I have been on jobs where I wished I had a big compressor on hand.....like changing shanks out of a bucket on site....had to use a gouging tip off the bottles....arc gouger would have cut the time in half and been much neater.
I really cannot think of a weld process that is more dangerous.....respect, planning and care are necessary....maybe that's why so many hate it???? Leather is your friend! LOL The worst welding related injury I have ever seen was from an Air Arc.......think tennis shoes and vascular and orthopedic surgeons...tells you all you need to know, paint your own picture. Wielding air arcs inside of vessels is a whole boatload of fun all by itself.....it takes practice on seams not to shoot it right back up your own a&&.
But even with that kind of stuff against it ....If I was running a portable rig I would want enough air compressor to use an air arc.....it would save me money+Time+ do a neater job on all kinds of repairs then the alternatives. Would I use it to cut out a fillet on 14 ga material.....no I rekon not I would use my grinder. They both have there place ya know?
Tommy
I use air arc over grinding whenever possible. It dont matter if it is overhead, horizontal flat, it doesn't matter as long as you know the proper way to use one. There will be no more sparks hitting you than a grinder. After your finished you shouldn't even have to pick up a grinder. If you ever have to make a repair on a weld it is alot easier to see the repair with an air arc than grinding also.
Not owning one is possably the best answer, who needs black lung or wasted eardrums? Maybe one of the worst things ever invented. Give me a straight torch with a gouging tip any day. That works for me anyway. Now a lance is a whole different subject.
Just my 2cents
Pretty hard to burn out a brass or bronze alloy bushing with a torch, though. Piece of cake with an air arc. And as for stuff in your lungs - that grinder dust just kills me.
Ive used the "Slice" (oxgen lance) to blow out several large stubborn pins on undercarriges of big dozer
it uses a hollow aluminum tube with magneseum wires in it as the electrode, and blows 80psi of oxygen through the tube, and you only need an electrical source to light it, a 12v car battery can be used
I hate CAC, but it has its uses nothing cuts tubes out better in refractory in the boiler or slices off skin caseing better. Leathers are your best friend but you can still get blistered from the real hot ones if you are not careful. I agree with the training need before anyone does any critical work with it. My training was, Hey kid can you use air arc? I replied, What? He said, I have it set see if you can cut this peice of metal off? I did and the rest is history. I learned fast from the old timers busting my chops about how bad a job I did. I then would always say, Then show me?
Unfortunatly I have seen this practice alot.
Now you talk about fumes and sparks. The lance makes air arc look pretty tame.
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