Welding aluminun with scratch start tig

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I was talking to a very old welder and he told me that he welded aluminum with scratch start tig long before HF came out. He said he would light up on a peice of copper and carry the arc over to where he wanted to weld. He said he was using AC.Has anyone ever done this and does it work.Sounds kind of far fetched to me!
Reply:Why is it far fetched? You don't need HF to do aluminum. I did scratch start tig aluminum on my htp 221. I'll go try it on the thermal arc 186 tonight if you want me to.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Yes it works. That was how I first did it, either in dc or in ax with my freq box. A modern TIG makes life much easier though.
Reply:Originally Posted by walkerYes it works. That was how I first did it, either in dc or in ax with my freq box. A modern TIG makes life much easier though.
Reply:Originally Posted by GambleWhy is it far fetched? You don't need HF to do aluminum. I did scratch start tig aluminum on my htp 221. I'll go try it on the thermal arc 186 tonight if you want me to.
Reply:Originally Posted by kctgbPlease do and record and post it as I would love to see how it's done.
Reply:id love to learn how its doneyou ain't gotta eat it
Reply:DCEN with 100% helium. Pretty much cut your amps in half from AC with 100% argon. Only problem is you have to make short welds, no way to control the heat, as the heat builds up in the material.Here is some I did on DC with a Tig rig. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:I've no doubt it works. I would expect contamination of the tungsten, though maybe copper won't contaminate as much as aluminum. I wondered if you could lay another tungsten on the workpiece and light up on it?
Reply:Originally Posted by CEPDCEN with 100% helium. Pretty much cut your amps in half from AC with 100% argon. Only problem is you have to make short welds, no way to control the heat, as the heat builds up in the material.Here is some I did on DC with a Tig rig.
Reply:Originally Posted by Willie BI've no doubt it works. I would expect contamination of the tungsten, though maybe copper won't contaminate as much as aluminum. I wondered if you could lay another tungsten on the workpiece and light up on it?
Reply:Hello kctqb, if he was using AC current the arc would extinguish without the HF. The zero current crossover point in AC without HF to carry it through the dead spot would not allow for a steady arc. DC straight polarity on aluminum is another animal altogether. You can weld aluminum with DC- providing that you are using Helium as a shielding gas and you pay close attention to the cleanliness of the parts being welded(they gotta be clean, clean, clean).Newer inverter style machines are able to drop out the HF in some instances due to the higher frequencies that the AC current shift is occurring at. They may only use the HF to initiate the arc and then switch it off during the rest of the process. There were a number of older CC stick welding machines that had HF generators piggybacked onto them or built-in. I had a MidStates tap type AC arc welder with a HF box on top of it and it would scratch-start and weld aluminum very well. It was also very nice to work with when you wanted to run some E7018, worked wonders with the HF start feature. You will see various HF generators built by a number of the biggies as well as a number of others. When you incorporate one of these onto an AC stick welder it will perform GTAW welds on aluminum by the "proximity" start method, meaning when the electrode is close enough for the HF to bridge to the work your welding will commence. This sort of GTAW on aluminum is very tricky when you are trying to weld differing thicknesses or when you get close to the end of a weld seam. I used to start the weld on the portion of the weld seam where it would end and weld about an inch in or so and then go to the other end and start the weld and meet the two welds together where I had left off with the first portion of the bead, in that manner it prevented over-heating of the end of the bead near the edge. Most of these machines didn't have the ability to utilize a foot pedal or other sort of current control while welding. That's my $.02 to add to this conversation. Best regards, Allanaevald
Reply:Just did lift arc on the 186. Touch the tungsten, hit the pedal and lift. Works really nice.Allan,I see your point where the arc would "shut off" crossing over the 0 point, but to me it really doesn't make sense. And AC stick welder has to cross over 0 and there is no HF in there. You still have a CC power source and still have a consistent arc. I don't have an old buzz box to test it on though. If I to my dads this weekend I'll bring my torch and see if he can dig his out.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Originally Posted by GambleJust did lift arc on the 186. Touch the tungsten, hit the pedal and lift. Works really nice.Allan,I see your point where the arc would "shut off" crossing over the 0 point, but to me it really doesn't make sense. And AC stick welder has to cross over 0 and there is no HF in there. You still have a CC power source and still have a consistent arc. I don't have an old buzz box to test it on though. If I to my dads this weekend I'll bring my torch and see if he can dig his out.
Reply:Hello Gamble, if you are talking about stick welding with an AC buzz box, there are stabilizers in the fluxes for SMAW that allow the arc to continue to work without losing electrical continuity at the 0 point(crossover). Consider E6010 and E6011 electrodes, the E6010 is a DC only electrode and will not work worth a hoot on an AC buzz box. The E6011(AC, DC rated) will, however, difference.... arc stabilizers in the flux of the E6011 electrode. With GTAW you have no "fluxes or stabilizers" to assist with the arcs ability to maintain itself, thus it needs the HF to maintain the arc or the advanced circuitry of a newer inverter power source. Best regards, Allanaevald
Reply:I did a little bit more investigating to see if I could find a better explanation to support my statements about AC GTAW with or without HF. I believe that if you read this article by one of Lincoln's welding engineers it might make a bit of sense out of what has been discussed thus far. You have to fit the pieces together a bit because he doesn't specifically answer the questions that I believe have been brought up here. In particular note the statements about conventional 60HZ CC welders versus 20,000HZ inverter power sources. Best regards, Allanhttp://www.treatrade.hr/pdf/DM/alum205.pdfaevald
Reply:Originally Posted by kctgbHow do you stop the weld without post flow and not get a crater or some porosity.
Reply:Allan, you said pretty much what I was going to. I remember reading something similar on Miller's site a while back. I'd have to dig to find the article. Older transformers with their sine wave shape are very different than the newer modern inverters with their multi form wave shapes and they can act very different even though they are both "AC". Unlike the sloping change in current used by transformers, inverters can rapidly go from max + to max - instantly and many times at speeds impossible with true sine wave or even square wave transformers. This makes them a completely different animal. My limited understanding from the article was that the change was so rapid with newer inverters, that the arc didn't really have a chance to extinguish before it had changed polarity..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by kctgbWhat kind of tig rig? was it a dc stick welder and scratch start tig.
Reply:Hello CEP, are those welds with DC- and helium? I am asking because there may be some confusion between all of the different machine types and processes that have been discussed so far. As I see It so far:AC buzz box, transformer type without HF- try to scratch-start GTAW aluminum with this combination and Argon shielding and I don't believe that it will be successful.AC buzz box with HF add-on or built-in- can successfully HF start GTAW aluminum with this combination and Argon shielding gas.DC/CC stick power source with or without HF or Lift-Arc start- can successfully scratch-start or lift-arc start GTAW aluminum by using Helium shielding gas.AC/DC inverter power source with or without HF or Lift-Arc strat- can successfully lift-arc, HF start, or scratch start GTAW aluminum by using Argon shielding gas with or without HF on AC current due to high switching speeds of this type of power source. DC scratch-start, HF start, or lift-arc start GTAW of aluminum also possible with use of Helium shielding gas.I just had to throw this out there to prevent my own confusion of the subject that is being discussed here. Best regards everyone, Allanaevald
Reply:Originally Posted by aevaldHello CEP, are those welds with DC- and helium?