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  • Plasma or Air Carbon Arc Gouging

    I have recently acquired a number of implements (loader buckets, pallet forks, etc.) that I want to convert for use with the Bob Cat Quick Attach system. I need to remove heavily welded ears and brackets to do this and I want to remove them as quickly and cleanly as possible so as to minimize grinding cleanup and damage to the implement. I believe that some form of gouging is the best way to undo all these welds. I have never gouged before but can add that capability in two ways with the equipment that I have and I am wondering which is the best way to go.

    One option I have is to get a gouging tip for my Thermal Dynamics XL 100 plasma cutter. Another way is to get a carbon arc torch for use with my Miller Trailblazer 302g engine driven welder. The XL 100 can plasma gouge with 80 amps at 112 volts DC. The Trailblazer is rated to use only up to 3/16" carbon rods with a carbon arc torch and this size rod can only take up to 250 amps.

    I realize that there are pros and cons to both systems and it doesn't cost much for me to add both capabilities so I am going to get both anyway. But as I start experimenting, what approach will likely blow the most metal away the fastest and the cleanest?

    I am guessing that the physics involved in a plasma gouge makes 80 amps in that mode perhaps more powerful than 250 amps in a carbon arc process. And there may be other factors to consider as well such as the ability to manipulate a carbon rod into tighter spaces than the head of a plasma torch. So I will probably end up using both ways, but given ideal conditions for each process, which is likely to be the most powerful for me?
    Bill Smith

  • #2
    Welcome Bill!

    This is where you'll find HAWK and the other guys I was telling you about at AWS who can really tell you what the Trailblazer can do with carbon arc gouging. I just recently got my CAC torch, so I'm still in the learning phase, too.

    Comment


    • #3
      You should be able to gouge real easy with 1/4" carbons, and acceptable with 5/16.
      I have NEVER tried to gouge with plasma, but I have run hundreds of hours on a Airarc, and it is a very good process, period.
      Also, don't overlook a scarfing tip for your OA torch.
      Jeff
      Jeff

      Comment


      • #4
        i have done both processes and i like the carbon arc gouging the best in a situation like this. it is much easier to gouge out exactly just the weld with the carbon arc, the plasma works too but is much harder to tell the diffrence between what you want to keep and what you want to go, plus with using the plasma i find it difficult to controll the depth of cut but with the carbon arc it's a breese. the fact of the matter is i could live without my plasma all together but for working on heavy weldments you prety much have to be equiped with the carbon arc! did i say i could live without my plasma.....mabey i lied! try them both out! make sure you cover up though!!
        The one that dies with the most tools wins

        If it's worth having, it's worth working for

        Comment


        • #5
          I have a TB302G and an Ingersol-Rand 175CFM diesel air compressor, so I'm pretty close to what I need to do some4 air arc gouging. There are times when I want to cut something apart that is really heavy and welded together with deep, penetrating welds - so much so that it's hard to do with a cutting tourch. I'm guessing this is where the air arc would come in.

          I've never even seen anyone using an air arc so what else do I need to get equipment wise?
          Millermatic 35
          Miller TB302G
          Ellis 1800
          Smith & Victor Torches
          Optrel Satellite
          Arcair K4000
          Ingersoll-Rand 175CFM Diesel Air Compressor
          Home Made Welding Trailer

          Comment


          • #6
            Jeff and Tigman, your comments are in agreement with what I am seeing from other forums. Sounds like air carbon arc is actually much preferred over plasma gouging for removing welds. And I definitely want to go faster and cleaner than what I can personally do with an OA torch.

            At this web page http://www.thermadyne.com/uplFiles/p...89_250_008.pdf the min and max amperage for 1/4" carbons is 300 to 400 amps. Given that a 302 TB is rated at 300 amps it seems that a 1/4" carbon would easily exceed the capacity of a TB. And with only a 3/16" carbon rod at up to 250 amps, is air carbon arc gouging still efficient for removing heavy welds?

            I am also hearing that using a 3/8" rod requiring 450-600 amps would be the ideal capacity for my application. Air carbon arc torches, even up to 1000 amp capacity, are cheap on eBay (saw one go for $131), but it's the power source that's the bigger issue. Can find some cheap three phase welding power sources at 600 amps (about $275), but I don't have 3 phase power and I am wondering what horsepower size 3 phase rotary converter would be needed to power a 600 amp 3 phase welding power source. Would probably be pretty expensive although I would like to have one for other uses as well.

            In the meantime, can anyone comment about how well a 3/16" carbon rod at 250 amps can remove deep welds?
            Bill Smith

            Comment


            • #7
              Originally posted by bsmith
              In the meantime, can anyone comment about how well a 3/16" carbon rod at 250 amps can remove deep welds?
              Bill Smith
              It will get the job done. The airarc adapter is a simple and inexpensive thing--- basically a different stinger with some air holes around the rod holder and a place to snap couple your air line on to it. Ours have a pigtail for the welding lead as well, and if you have tweco splice in your lead you can simply unplug your regular stinger and plug this one on---snap couple up the air line, buy some carbon arc rods and go.

              As noted, wear fire proof pants, cause with the compressed air and lots of sparks you will need a bucket of water to put the fire out one your britches before the job is done if you don't.

              AT least the plasma cutter I have (a lincoln) offers a special tip for gouging that has bigger hole in the end of it. this spreads the fire around for a gouge instead of the more focused cut.

              We've use a basic miller bobcat for air arcing in simlar things to what you are talking about. the smaller carbons just take a little longer to get the job done but it will work just fine.

              One thing to remember---when you are running the welder 'wide open' pay some attention to its duty cycle rating. Most welders are less than 100% and full power, so when you change rods, think about letting the welder cool consistent with the duty cycle limitations applicable to your machine.
              rvannatta
              www.vannattabros.com
              Miller Bobcat 225G
              Miller Big 40 ('79 gasser)<gone>
              Miller 375 Plasma cutter<gone>
              Lincoln Vantage 400
              Lincoln Pro-Cut 80

              Comment


              • #8
                I don't care for gouging with a plasma cutter. I think is a lot of trouble and is not all it is cracked up to be. I can tell you the TB301 or 302 will easliy run a 1/4" round carbon rod on DCRP. I push a 185CFM with and IR compressor, but it is certainly overkill. A 13+ CFM compressor will keep up well enough. The TB302G will run shallow gouges with a 5/16 rod with plenty of air behind if you take your time. CAC-A is the preferable choice. My second option is O/A with a scarfing tip. These take practice to master more so than CAC-A.

                Comment


                • #9
                  I would say that you definitely don't want 3/8" for what you are working on, even if you had the machine to run them.

                  Here is a 3/8 carbon at work
                  Attached Files
                  Jeff

                  Comment


                  • #10
                    i have the capacity to run 5/8" carbon rods and very rarely stray from 1/4" they are the rod of choice the way it seems, 3/8" would be the next used most frequently. it's not so much going by the charts for rod size compared to machine size, a small machine will run a larger rod, you just can't go very deep or very fast. 3/16" rod will definatly work for your application it will just take a bit longer, not as long as torching or plasma cutting it apart though! one more thing you will want to invest in a nice needle scaler to remove the gouging slag from the parts, this tool will prove very handy in MANY applications so it's not just for the CAC process! it works great for removing paint and rust too!! also works for cleaning your lawn mower deck in the fall too! LOL!

                    here are a few pics of a 3/8" gouging rod in action, removing a 3/8" fillet weld.
                    http://img202.imageshack.us/img202/7082/gouging37cw.jpg
                    http://img202.imageshack.us/img202/4875/gouging21af.jpg
                    http://img202.imageshack.us/img202/8754/gouging16lf.jpg
                    The one that dies with the most tools wins

                    If it's worth having, it's worth working for

                    Comment


                    • #11
                      bsmith,
                      I`ve similar work to what you want to do with my 301G and 1/4 or 5/16" carbons.It will work just fine for your application also.Make sure you`ve got enough air and go to town.Once you try this out you will be suprised how well it does work. Don`t have any experience with the plasma but cant imagine it to be any better in this application.

                      Comment


                      • #12
                        bsmith, you've got pretty good advice about that gouging. Remember that the new 302 is no slouch, and i find mine runs about 10-15% hotter than other machines I have run, so keep that in mind with the ratings. I have a 20cfm compressor at 175psi, and run my cac (K4000) with about 100psi which probably means it uses about 22-23cfm, and it keeps up just right, a couple less cfm would mean I'd be spending time waiting for it. I run 1/4" carbons like the bees knees, but haven't tried anything larger, and like tigman was saying I probably never will, as I find that 1/4" works well for most of what I do. However, as much as I like my CAC-A, I don't use it for bucket/implement ear removal. I use my torch and put a big tip on it and start cutting. I can cut each ear of in about 5 mins, cutting right at the top of the welds, and then it takes just a couple more minutes to use the torch to wash off the remaining metal. Much faster than using CAC-A to remove all of the weld material and then beating them off. Also, it takes a little bit of practice to not over gouge a part, so keep that in mind. Last but not least, expect to get burned. My last bad one with CAC-A was a good splash of metal down the back of the neck and I had a full button up jacket on with the neck gaurd and a cap, but it snuck in there somewhere.
                        hre

                        Comment


                        • #13
                          Coal, get some 5/16 and try them. they make a nicer groove than 1/4, and your 302 should run them well. My 305 does. But, you need to be SMOOOOTH.
                          Try it you'll like it.
                          Jeff

                          Comment


                          • #14
                            On another forum, another guy raised the very valid point that plasma does have a considerable consumable expense so that is yet one more reason to use air carbon arc over plasma for gouging. Coalsmoke's burn warning and Tigman's pictures of fiery showers using 3/8" carbon rods are somewhat sobering. Can't treat CAC-A use like regular torch work. Gonna have to bundle up and think about where all the metal will fly before I start.

                            The other point is about the air needed. It seems that a lot of people on this forum and others suggest using way more air than I first thought necessary. At this web page http://www.thermadyne.com/uplFiles/p...89_250_008.pdf recommended air cfm and pressure ranges are 40-80 psi and 8-46 cfm depending on the particular application. Maybe carbon arc gouging is one of those things where it's very important to have at least the minimum air pressure and volume required while having extra doesn't hurt and probably helps. Hawk's suggestion that 13+ cfm would be enough jives with the Thermadyne web page recommendation and gives me some confidence I can come up with enough air flow and pressure.

                            And Jhall's good experience with a TB 305 working well even with 5/16" carbons makes me confident that my TB 302 would do fine with 1/4" carbons and probably 5/16" as soon as I can get SMOOOOTH with the process.
                            Thanks for all the good advice guys.
                            Bill Smith

                            Comment


                            • #15
                              I have a Ranger 305. You can adjust air flow with the valve on the torch to a certain degree. All in all, it's not much worse than cutting with a large oxy acet tip. You just need to be aware of where the sparks will go.
                              Jeff

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