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  • #16
    Originally posted by justanengineer
    First off, there is no such thing as scratch starting a tig. Miller calls it a Lift-Arc start
    Lift arc is an electronic system that allows arc starting without the use of HF where the environment makes that undesireable or imposible. A welding robot, or someone doing fabrication near live comuting equipment for example. Lift arc starts with the welding supply turned off. A pilot current is fed to the torch so that contact between the electrode and the base metal can be detected. The welding power supply is turned on as soon as contact with the base metal is broken, the arc being able to jump the tiny gap without any kind of HF assistance.

    Essentially what the OP has bought is an a constant current welding power supply, which would be just great for stick welding. Most of these are advertised as being able to do TIG also as TIG requires a power supply with the same characteristics. The arc is inititiated by making contact with base metal, just like it would be with arc. I recall that the usual advice was to use a bit of copper along side the weld for arc starting.
    Paul Compton
    www.morini-mania.co.uk
    http://www.youtube.com/user/EVguru

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    • #17
      keep trying

      I started TIG with one of the $200.00 HF 140 amp DC scratch start jobs. The first week trying I just about went nuts and destroyed a lot of tungsten. I was convinced the unit was defective and would have taken it back except for the fact I live 60 miles from the store. Then it just suddenly fell into place and I was laying down bead like mad. My friend who was an experienced tig weldor on his Miller inverter never could make my scratch start work for him!

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      • #18
        Scratch start is "scratch start", and there certainly is such a thing, did it for years and years.

        Use a motion similar to striking a match but with less motion and less friction. You will get it with practice.

        rollin'

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        • #19
          Have you stick welded before? I was wondering because as a beginner you can run into the same problem using stick. You pretty much have to get a big plate and just practice starting the arc over and over. It's a fine technique.

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          • #20
            Originally posted by plunger
            Also curious to know how to anchor pipes together so you can weld em straight.
            Plunger, see here.

            http://bbs.homeshopmachinist.net/showthread.php?t=49254

            Brian
            OPEN EYES, OPEN EARS, OPEN MIND

            THINK HARDER

            BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

            MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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            • #21
              Originally posted by plunger
              I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet.
              Yes. Rectangular lenses in the common reading glass strengths are readily available. They clip right into the welding helmet on the inside

              http://cgi.ebay.com/MAG-LENS-CHEATER...-/130480038932

              Dennis

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              • #22
                An update on my tig experience. I bought a cheap auto helmet and it has helped me immensely. Also I am starting to get the hang of the scratch arc. One has to have their tungston real sharp and kept real clean. The copper trick has helped because you can get an arc close to the workpiece. Using the cup to rest has also helped me. I find if I can start on a edge it is also easier as it is easier to pull away from the work.
                Wher I am now battling is doing plates at right angles.I am finding it hard to get the cup close enough to both plates. Would a smaller cup help.
                Also I tried stick welding with this setup. Same story. The stick sticks like crazy and is hard to get started.I am using a 6013e rod. it amazes me how much spatter it creates. Does a stick have a shelf life It feels more like a sparkler than a welding rod. I dont understand how the splatter can stick to the metal in little balls that I cant even knock off with a welding hammer. How does it fuse. Surely it cant make the parent metal hot enough to bond. I

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                • #23
                  Originally posted by plunger
                  I am also curious to know if One can get a lens made so you dont need to where glasses under your helmet. Also curious to know how to anchor pipes together so you can weld em straight. Also does any one have any photos of how a jig can be made to spin the pipe so that if I ever get good enough to weld i can spin the pipe while i weld. Although at this stage it doesnt feel like I will ever get there.
                  Heres a thread on clamps for pipe and other ideas
                  Glen
                  Been there, probably broke it, doing that!
                  I am not a lawyer, and never played one on TV!
                  All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or the suggested uses, Wear safety glasses, closed course, professionals only

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                  • #24
                    Originally posted by plunger
                    Also I tried stick welding with this setup. Same story. The stick sticks like crazy and is hard to get started.I am using a 6013e rod. it amazes me how much spatter it creates. Does a stick have a shelf life It feels more like a sparkler than a welding rod.
                    try some 7018. In class we went through the 6011, 6013 etc, and most of that seemed to be just as you say. Stuff inside the helmet bouncing off the safety glasses

                    the 7018 is well-behaved by comparison. but you can still stick it. I found in class that if I didn't think about it, I scratch started perfectly, but if I thought about doing it right, I'd stick it 5 times in a row.

                    I kept a piece of scrap handy to 'pop" the rod on if the slag got over the rod end.
                    1601

                    Keep eye on ball.
                    Hashim Khan

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                    • #25
                      Plunger - without sounding condescending - you just need to gather up a bunch of scrap and weld and weld and weld some more until you get the hang of it.

                      Pay particular attention to threads in the welding section of the forum where the guys are discussing welding preparation. Grinding off the scale, cleaning off the oils. See if you can find a thread discussing building a rod oven out of a 100 watt light bulb and an old metal bread box. Learn to use your hearing when you weld to judge the burning of flux on your stick welding. Learn the proper shaping of tungsten for the various types of TIG welding.

                      I know by experience it is instinctive to want to just grab a stick and watch it burn and hope for the best - but I'm sorry, it just doesn't work that way.

                      Even guys who weld 40hrs a week professionally often understate the necessity of proper preparation. But when you listen to them talk about how their day went, you'll always here them mentioning the preparation steps just as much as the actual welding.

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                      • #26
                        You never want to scratch start with tungsten. Once the electrode touches the work it's instantly contaminated and you will have an arc that wanders making it hard to control, especially for a beginner.
                        With HF your arc should jump with in 1/4" of your work depending on the current. Also proper pointing of the tungsten is very important to a stable arc. Don't point your tungsten on a wheel that you grind steel on as the steel deposits left in the wheel will transfer to the tungsten giving you hot spots and instability in the arc. Also the grain of your grind should not go around the dia of the electrode, it should go in line with it for better electron flow. The point of the electrode should have a slight flat spot, eg. 3/32" tungsten should have an .020 flat point. These are just some of the important things you should know.

                        JL.......................

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                        • #27
                          +1 for schooling

                          I will second the suggestion for attending a local junior college or such for formal schooling - you will be a better welder for it. If you think the cost is high, consider that you will probably use much more material for practice than the tuition!

                          I took this approach, and have never been sorry I took the time to do it right - best money and time I ever spent....
                          TexasTurnado

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                          • #28
                            Plates at right angles as in fillet welds, you can stick the tungsten out a little farther for them,get the tungsten as close as you can without touching, that is how you can get a nice tight bead..

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