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  1. Dec 19, 2017 #1

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    Some of you might find this interesting. These photos were posted on Facebook today by a well known company building fuselages and selling them.

    They are MIG welded, they are atrocious by any standards. I saw the welder in one of the photos, it looked like a little Millermatic 185 which is a small machine for home use and very light industrial which is a stretch. Sub $1,000 machine.
    FB_IMG_1513633605092~2.jpg

    FB_IMG_1513633610180~2.jpg

    In the comments a couple people chimed in a said something but the owner started saying how the industry uses MIG now and it's the new standard.

    Yes, some companies do use MIG but they are very high priced units that are designed to manage heat (amp) in a manner that's not even close to the little machines. And these professional machines are ran buy professional welders who are skilled and do this every day all day.

    Unfortunately people will see that company post and assume they can buy a cheap MIG machine and build airplanes which is crazy. While it's possible to do it preheating with a torch it's ludicrous for a beginner to assume the can do it safely and consistently.

    I can't believe this company posted that to be honest. I lost all respect for them. I won't mention the name but they focus on very old replicas and it's not hard to figure out..

    Anyhow. If you're considering MIG as some means of making the process affordable this is NOT where you want to save money.
     
  2. Dec 19, 2017 #2

    rbrochey

    rbrochey

    rbrochey

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    Think I'll stick with my TIG practicing I like the process and MIG seems to go against everything I've read about fuselage welding... but I'm no expert. Thanks for bringing this to everyone's attention.
     
  3. Dec 19, 2017 #3

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    MIG is great if the machine has the correct capacity for the work, which are not consumer machines.

    I have pretty good experience overall, I would never trust myself to MIG .035" tubing. TIG or Oxy.
     
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  4. Dec 19, 2017 #4

    TFF

    TFF

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    American Champion uses MIG. The operator, while welding, is constantly moving the amp knob like working a foot pedal on a TIG. They learned they could not point and shoot, but had to be active on the amps. Way too hard to do for an amateur. Much easier to TIG or OA and nicer too.
     
  5. Dec 19, 2017 #5

    Tiger Tim

    Tiger Tim

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    I know the company you mean and I know of one of their kits that had a very minor incident after a few short flight hours and ended up being written off. The owner scrapped The whole works as soon as he saw how poorly built the fuselage was.
     
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  6. Dec 19, 2017 #6

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    Yeah, lots of cold spots because the operator is always turning and adjusting. And of course stops and starts.

    If you can keep the gun moving and you're skilled enough to hold your distance and speed, yeah. You have to weld every day to pull that off.
     
  7. Dec 19, 2017 #7

    TerryM76

    TerryM76

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    Any opposition to using MIG for tack welds?
     
  8. Dec 19, 2017 #8

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    Sure you can, I wouldn't though.

    There's a potential issue. Ideally you want small talk welds, not the best scenario I suppose.
     
    Last edited: Dec 19, 2017
  9. Dec 19, 2017 #9

    Turd Ferguson

    Turd Ferguson

    Turd Ferguson

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    Jim C tack welds his Tailwinds with mig. That man can build a fuselage in one day
     
  10. Dec 19, 2017 #10

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    See, when you tack with a MIG the tacks tend to be kinda big, it's the nature of the process. This can kinda mess you up later on.

    Believe it or not tack welding is an art in itself. With O/A it's a fun little dance to tack weld, really quite enjoyable.

    TIG is a fun challenge too and you can really put in light tiny tacks.

    Myself, tack welding thin metal with a MIG is hard for me. Tack welding with a MIG on say, 1/8" and up is quite easy.
     
  11. Dec 19, 2017 #11

    Little Scrapper

    Little Scrapper

    Little Scrapper

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    He's retired and has built like 13 of the same thing. I've been to his hangar, he does nice work. It's just not realistic for most of us part time builders.
     
  12. Dec 19, 2017 #12

    Pops

    Pops

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    Same story here.
     
  13. Dec 19, 2017 #13

    Topaz

    Topaz

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    No offense, because you're clearly a skilled welder, but "Oxy" was the standard welding method for steel-tube fuselages for nearly a hundred years, and is still perfectly acceptable today. Let's not go saying that nothing but TIG is acceptable. That's patently absurd. The welds you showed are poor. That's more a reflection on the person doing the welds than the method chosen, "professional" or not.
     
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  14. Dec 19, 2017 #14

    Turd Ferguson

    Turd Ferguson

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    Maule has been MIG welding their fuselages for some time now and many kit build fuselages are mig welded.
     
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  15. Dec 19, 2017 #15

    Little Scrapper

    Little Scrapper

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    What the hell are you talking about? When did I say OA wasn't ok, I use it all the time including yesterday on my Cassutt?

    Maybe you didn't read what I wrote. I clearly explained that MIG is perfectly ok. I clearly explained that MIG requires skill. I clearly explained that there's a difference between cheap MIG machines and professional MIG machines designed for precise heat settings.

    So I have to ask you, what are you talking about??? I'm probably the biggest proponent of Oxyacetylene on this forum, 80% of my Cassutt is Oxyacetylene.

    I swear, this forum is like walking on eggshells shells let alone saying my words are patently absurd. What the hell is absurd about deciding to be honest with myself saying I'd never trust myself with MIG because I don't MIG every day. I know myself better than you do. And what welding experience do you have.

    This is just nuts.
     
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  16. Dec 19, 2017 #16

    Chris In Marshfield

    Chris In Marshfield

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    I read, “TIG or Oxy” from Scrap’s post in the section you quoted. I know he favors either.
     
  17. Dec 19, 2017 #17

    Jay Kempf

    Jay Kempf

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    MIG is prevalent now in manufacturing BUT... it is in robotic manufacturing. I work with two companies that use MIG exclusively for thin stainless sheet metal small intricate tanks with all kinds of tubing heat exchangers. Panasonic makes the welding stations I have seen. All that says it is possible to get amazing results with MIG if you can repeat exactly the same thing every time and set it up properly to the task. Probably not possible in DIY less expensive machine world. Would be nice if it was cause MIG is easy setup and fast.
     
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  18. Dec 19, 2017 #18

    Topaz

    Topaz

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    Whoa! Chill out a just a little bit there, big guy. It was late and clearly I misread what you said. Now that it's morning and I've had some sleep, I can see that. So very, very sorry. Sheesh.

    No need to go off like a bomb in a situation like this. This forum would also be better if people would stop taking everything so damned personally. If someone is wrong, misinterprets you, or otherwise makes a hash of what you posted, berating them is about the worst way to go. Take the time to educate. Take the time to reach some understanding. Going off like you did here helps nothing.
     
  19. Dec 19, 2017 #19

    Himat

    Himat

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    Two questions from a non-welder. I can see that excessive material have been added, the weld surface look uneven and there are signs that the tubes have been hot adjacent to the weld. Some centimetre from the weld the tube turn blue, I take that as a sign of the heating.

    But is the strength of the weld compromised?

    Is it from the pictures possible to see if weld penetration is insufficient?
     
  20. Dec 19, 2017 #20

    Little Scrapper

    Little Scrapper

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    The outside edge of a weld is always the tell tale sign. There's massive lack of penetration that are visible. This is primarily caused by starting and stopping, MIG is a bit tricky in that respect.

    Good eye on that heat zone! Unfortunately the visibility of that band means something different for MIG than it does TIG or Oxyacetylene.

    Starting and stopping with TIG or Oxyacetylene are ok because of how the part is heated. With MIG, starting where you stopped leaves a cold spot with non penetration because there's no preheating. Makes sense?

    This is why I always recommend people start with Oxyacetylene because the heat blanket keeps a novice fairly safe.

    Robots can MIG in one pass.

    An experienced MIG welder knows how to stop right, they taper quickly and restart by back stepping and pausing in the prior stop.
     

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