Convert TIG to MIG?

  1. lostcookie New Member

    Messages:
    24
    Location:
    UK
    OK, zero luck finding even a secondhand AC MIG that doesn't look like it hasn't spent time at the bottom of a lake/critical bits missing like a power cable/"not used for some years"/looks like a herd of elephants sat on it or used it as a football.

    I've found this on ebay;https://www.ebay.co.uk/itm/ARC-TIG-...828992?hash=item3b31ef2e40:g:EiEAAOSwoutcj3Ps

    It lacks a euro connector but the only spool guns I can find are either euro or have no plugs? Can such a machine be converted to MIG?
     
  2. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    In a word, no.

    MIG needs a constant voltage supply. That's a constant current supply. They aren't interchangeable, unless designed to output both ways from the start. If you're interested, you can read up on why constant current doesn't work for MIG. At least, not at the amperages that normal people work at.

    It's also an overpriced piece of chinese junk :whistle:
     
  3. Wozzaaah

    Wozzaaah The wizard of woz Staff Member

    Messages:
    15,194
    Wiltshire, UK
    I wouldn't say £400 was overpriced for a brand new AC/DC machine at all, regardless of it's country of origin.
     
  4. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    I'm slightly biased against anything chinese... but it's a WSME machine, notorious for failing straight out of the box, and it's telling straight porky pies on the label... if it was a true 250 amp machine, it would draw a lot more than 16 amps input.
    Anyways that's by the by :) Even if it was a top end Fronius or Lorch, the answer would be the same: Not going to run a MIG spoolgun, not properly anyway.
     
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  5. lostcookie New Member

    Messages:
    24
    Location:
    UK
    Munkul, you are not the only one who doesn't like Chinese stuff (apart from the food) but the budget just isn't there for something better. I do not believe the specs and in my opinion it's probably only good for around 150-170a anyway which should be enough for the thinner items I have to weld. Just heard of yet another green Chinese lathe full of casting sand but that's just a side note.

    Another similar one but this requires a 30a supply;

    https://www.ebay.co.uk/itm/Blacklin...rentrq:506da5ef1750aad7249dc243fff1b3ec|iid:1

    In theory TIG would do some of what I want BUT I can see it being very difficult getting the torch into the bottom of 50mm angle (I have to weld braces into it). I've been watching TIG videos on youtube and I have no problem soldering things and to my eyes it looks very like this. Any ideas on how the torch could be configured to do this? This was the reason for MIG which could get in there.
     
    Last edited: Oct 22, 2020
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  6. tigdlo Member

    Messages:
    88
    Location:
    UK
    Are you describing an inside 90° corner joint? If so you shouldnt have a problem with TIG. What are you making and why do you want an AC mig?
     
  7. Tom Mooijman Member

    Messages:
    15
    Location:
    The Netherlands - Rotterdam
    I think you will have more luck getting a AC TIG to weld aluminium than a cheap MIG machine. TIG would be a preferred method in some respects anyway, it should do just about anything a MIG does (and more), and it should get you going with less hassle. There is a good and elaborate thread on the Sherman AC/DC 206P tig machine, I've read that there are lot's of people who are happy with it. It's very cheap for an AC/DC TIG, and from what the seller posted on the forum there is a decent warranty as well.
    TIG is by all means not the easiest process to learn, but it'll give a great deal of satisfaction once you get the hang of it.
     
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  8. lostcookie New Member

    Messages:
    24
    Location:
    UK
    Tigdlo, I'm trying to weld braces into some angle to stop it flexing when it gets loaded up. The braces are made from 30x30mm by 3mm wall box that I already had to save money on materials. Angle is 5mm thick...yes, I know it will be fun trying to set any machine to get this right but I have plenty of offcuts to practice on. In answer to your question of why an AC MIG...because some people are telling me it must be AC and some are saying DC is fine (not on this forum). What a great way to confuse someone new to welding!

    Tom, TIG could be the answer but my motor control function is poor at best and given I could not gas weld with filler rod when at college I doubt this would work for me but I am willing to look.
     
  9. Hood

    Hood If it walks like a duck....

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    12,563
    Location:
    Carnoustie, Scotland
    Tig has to be AC for Aluminium as you need positive part of the cycle to clean the oxide but if it was all positive (as in DC) then the electrode would get too hot and melt thus you use AC as it alternates between positive and negative and allows you to clean and weld without melting the electrode.

    Mig welding is DC+ (almost always anyway, you do get AC) because the electrode is the wire and you want it to melt so DC positive is perfect for Mig.
     
  10. willie.macleod

    willie.macleod Member

    Messages:
    324
    Location:
    Western Isles, Scotland
    What are you making? You are talking about spending quite a lot of money on equipment which may not be necessary to achieve your end goal. Welding may not be the best method of connecting the components - are they both the same metal for example?

    As @Hood has already explained you can use your standard MIG welder with the correct aluminium wire and pure argon gas (not a mix) for welding aluminium. A decent torch liner, correctly set wire tension and the right torch tip/rollers are also required.
     
  11. lostcookie New Member

    Messages:
    24
    Location:
    UK
    It's a static tandem scissor lift which is designed to come to pieces because where it's going has awful access. It's all ally and welding is the only option because no glue stands a chance, I need to stop the angle "kicking out" when a load is put on it. I have a friend doing the actual scissors and mechanism but I can speed up the build if I do all the smaller parts.

    I'm starting from no machine at all which in some ways makes it easy but also difficult finding the right one.
     
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  12. willie.macleod

    willie.macleod Member

    Messages:
    324
    Location:
    Western Isles, Scotland
    Starting to sound a bit sketchy, a lifting device is not a great idea for a beginner to start learning a new welding process, you might find it comes to pieces at the wrong time. Do you have plans/3d CAD model? You might be able to get some useful feedback and avoid welding altogether.
     
  13. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    Hood is spot on regarding AC/DC current :)

    You know, you could probably give it to a small fabrication shop with aluminium welding experience, and pay them to weld it professionally for about half of your total machine budget, maybe less. It would be a lot safer, and a lot less frustrating.

    Designing some lifting equipment for the first time, and attempting to make it with a process you're not familiar, when you have next to no experience with welding (and therefore metal fabrication in general I assume)...

    ...You're not only trying to run before you can crawl, you're already trying to pole vault! I'm not meaning to sound negative, I know people can do amazing things if they want something enough. It's just that you're trying to do it on such a tight budget that you'll inevitably cut corners, and compromise the whole thing. You haven't even started to think about what constitutes a sound weld, for example.

    I assume it's only for your own use and not for a workplace? Because such a device will be illegal in a workplace without LOLER testing etc.
     
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  14. lostcookie New Member

    Messages:
    24
    Location:
    UK
    Don't worry, I'm not doing the welding on the bases nor the scissors. Because there is so much small welding it would be easier if I did it that way I can speed things along a bit. There are no actual drawings; this is being copied from a commercial scissor lift which is useless for what I want (as are virtually all commercial items) because the ram/pump assembly hangs below the underside of the base frame and I want to get as much difference in the height as possible. What I hope to get is around 200mm at the bottom to around 1200mm at max height.
     
  15. Mr Roo

    Mr Roo Member

    Messages:
    430
    Location:
    Edinburgh
    can’t see any issue with a shortened tungsten and a stubby back cap on the torch.

    i regularly TIG some awkward shapes (including recently welding a cracked bolting point on a gearbox in situ...) - flexihead torch with short caps does the job!
     
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