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Thread: Tig Newbie

  1. #1
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    Default Tig Newbie

    Hi All, My first thread on this forum, I have a Unitig 200AC/DC welder that I have had for about 12 months, and have done a lot of practicing Tig on Aluminium, but I always have the same problem that I cannot control the heat, unless I turn Amps right down, then I get unstable arc. Any suggestions would be greatly appreciated, also your opinion of this welder?

  2. #2
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    First question - are you welding with a pedal or thumb control at all?

    Michael

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    Quote Originally Posted by Michael G View Post
    First question - are you welding with a pedal or thumb control at all?

    Michael
    Thumb control Michael.

    Alan.

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    I'm probably novice grade too when it comes to TIG (I certainly get a ribbing for it at work from the fitters), but the best advice I ever got given about Al TIG welding was "get it hot enough that it looks like it is about to melt and then jam the filler in". Heat control is as much about using the filler to reduce the material temperature as it is getting the amps right. Prior to learning this vital bit of information my welds were too cold (as I was trying not to melt the Al too much). Perhaps add filler more often into the weld puddle and see if that helps?

    Michael

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    Have actually tried that on many occasions but still no go.

    Alan

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    TIG is a very 'controlled' orderly process and you should be able to set it up so you've got heaps of time to react to what you're seeing in the weld.
    The trick for aluminium is to try and go as high with the amperage as you can manage and go as quick as you can without compromising control.
    If you send some photos or are more specific about what you are having trouble with then you'll get more specific suggestions
    Cheers
    - Mick

  7. #7
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    Quote Originally Posted by awpy View Post
    Hi All, My first thread on this forum, I have a Unitig 200AC/DC welder that I have had for about 12 months, and have done a lot of practicing Tig on Aluminium, but I always have the same problem that I cannot control the heat, unless I turn Amps right down, then I get unstable arc. Any suggestions would be greatly appreciated, also your opinion of this welder?
    I got a tig welder for the first time 2 years ago and spent a year doing only DC/steel, no aluminium. I had tried ac on Aluminium a few times just to see if i could, but if I turned the amps up high enough to get it going quickly, then used the pedal to control it, I always ended up with the pedal backed right off, to the point of almost cutting out, and still melting everything in sight, even moving as fast as possible.

    At the time, I just thought aluminium was much harder than steel, so I just ignored it all and carried on practicing steel until I was good enough. Turned out to be a fault in my welder though. After it was fixed, I didn't find aliuminium much harder than steel, just different.

    I guess its unlikely to be the welder, but maybe try another if you can, or have someone check out yours. Its a problem people who teach themselves can have, is knowing if its us or the equipment. Mostly its us of course!

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    The problem that you described in your thread sounds identical to mine, so I think there is a problem with the welder. Will have it checked out, then sell same and look for good secondhand Miller or similar.

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    Thanks to all who replied to my post, Appreciated.

    Alan

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    Quote Originally Posted by awpy View Post
    The problem that you described in your thread sounds identical to mine, so I think there is a problem with the welder. Will have it checked out, then sell same and look for good secondhand Miller or similar.
    If it is the same fault, you will notice that the arc doesn't turn down as much as you would expect, and just continues pouring heat into the metal. It should actually turn down pretty much as much as you would expect. Having never used AC before, I didn't realise that at the time, especially as it did turn down a bit. It wasn't until I repaired the welder for a different fault that it all started working.

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    Quote Originally Posted by WelderMick View Post
    The trick for aluminium is to try and go as high with the amperage as you can manage and go as quick as you can without compromising control.
    +1

    That is the only way I have found to do Al successfully - BTW I don't have any "in welding current control" as it's an old transformer TIG (i.e. no foot pedal/thumb wheel).

    If you go too low on the amps, you tend to pour a lot of heat into the surrounding area while trying to produce a usable weld pool and eventually it all just collapses.
    Cheers.

    Vernon.
    __________________________________________________
    Bite off more than you can chew and then chew like crazy.

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    Few people want to do it, but the old running beads on 3-5mm plate is about as good a method of starting to develope the skills to successfully weld ally as there is. Learning what to look for as your puddle starts and learning to recognise the signs of impending melt through.
    Before you sell your welder, try to get someone who knows their stuff and get them to give it a try. It's not too often that we venture much below 65 or 70A when welding ally, and more often sit in the 85A+ range for most general work 1.6mm and up. Ally likes a bit of power due to it's thermal conductivity.
    I know many people love them, but I personally believe that thumb wheels, foot controls and 4T settings unnecessarily complicate the learning process and are best reserved for more specialised applications in the hands of a skilled operator. Sort of like learning to drive in Michael Schumacher's Ferrari - too many bells and whistles, too confusing, so youend up losing concentration on the task and crashing.
    Not always easy, but if you can find a friendly fabrication shop, they may help you learn for a small fee, which could be money well spent. In my previous workplace we did it for a few people, but not all shops may be as helpful.

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    Quote Originally Posted by Karl Robbers View Post
    I know many people love them, but I personally believe that thumb wheels, foot controls and 4T settings unnecessarily complicate the learning process
    I use my foot pedal 50% time and torch 2T with about 1.5 sec downslope at other times - rarely have the need to use/try anything else.

    I'd have to disagree regarding foot pedals... if you're working at a bench I found it the most natural thing in the world to use and if honestly I don't think it complicates matters much at all. In fact, it lets you forget about fumbling for the torch button, and lets you hold the torch exactly as you want - letting you concentrate on arc length and angle etc. which I think we all agree are critical. You can use it as an off/on switch only, then graduate to varying amperage using the pedal later.

    On the other hand, I tried the 4T torch setting for all of 10 minutes and hated every second of it. I've never tried a thumb control, but would expect that it would take a lot of getting used to - but great in the right setting when mastered.

    Cheers
    - Mick

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    Quote Originally Posted by WelderMick View Post
    I'd have to disagree regarding foot pedals... if you're working at a bench I found it the most natural thing in the world to use and if honestly I don't think it complicates matters much at all. In fact, it lets you forget about fumbling for the torch button, and lets you hold the torch exactly as you want - letting you concentrate on arc length and angle etc. which I think we all agree are critical. You can use it as an off/on switch only, then graduate to varying amperage using the pedal later.

    On the other hand, I tried the 4T torch setting for all of 10 minutes and hated every second of it. I've never tried a thumb control, but would expect that it would take a lot of getting used to - but great in the right setting when mastered.

    Cheers
    - Mick
    Fair point about using the foot pedal as an on/off device in place of the torch switch.
    I've never really got on with thumb wheels but I did use a Fronius tig torch that had a simple toggle that you rocked either forward or backwards to vary the amperage and that did work very well. CK (and probably others) make a torch with a slider for amperage control that I reckon would be quite intuitive.
    It's all horses for courses I guess and it's not that long ago that we were tigging with pie heaters, no square wave, no AC balance or frequency control

  15. #15
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    I do quite a lot of steel but not much aluminium. My results on aluminium are pretty good, but I pedal the hell out of it. E.g. a few weeks ago I was doing some stuff with maybe 5-6mm plate pieces and probably had the machine at 170A, flooring it but as soon as the puddle starts (within maybe 2 seconds) dropping to about 2/3-3/4 and by the end of a run down to about 1/2. I couldn't say without someone watching the machine amps while pedaling but that's what my foot tells me.

    I move about twice as fast on aluminium, fast enough that I can barely keep up feeding and I've got to be on the ball re. moving my hands along too. And I don't slouch on steel either. I prefer lots of heat and fast travel.

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