Welding Aluminum

Discussion in 'Maintenance Bay' started by timwinters, Apr 21, 2015.

  1. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    An intake tube is not a structural part....did you see the aluminum welds in the pic I posted?:rolleyes2:

    ...yes they do crack, so remember to inspect them well.:rolleyes:
     
  2. Tom-D

    Tom-D Taxi to Parking

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    Most of those weld procedures are an authorized shop procedure approved by the FAA under the CRS certificate.

    How many A&Ps in the field have the equipment to weld these? or will find out what alloy to use when welding? Most A&Ps will simply send them to shops like Divco.
     
  3. Arrow67

    Arrow67 Pre-Flight

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    If you are having cracks re-form after welding, the weld process was not done properly. Most likely preparing the crack for welding.
     
  4. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    Tom....remember your welding practical project?....you did have that right? :D

    A&P's are authorized to weld....and inspect them too.
     
  5. Tom-D

    Tom-D Taxi to Parking

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    Yes I saw them, so what? they are not heat treated either
     
  6. Tom-D

    Tom-D Taxi to Parking

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    Yes I remember that was 1960, all we did was a fish mouth repair on a 4130 steel tube. I never welded aluminum until I took the welding course at Skagit Valley Comm Collage, where I got my ATA in welding technology.
     
  7. Tom-D

    Tom-D Taxi to Parking

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    Welding causes heat treatment, the cracks develop due to no annealing after welding.
     
  8. tehmightypirate

    tehmightypirate Line Up and Wait

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    Hey, don't lump everyone in there. I simply wanted to educate people on the unique properties of welded aluminum connections lest they try this on something more critical like a wing spar.

    But for anyone out there who also wants to experiment with their airplane I don't care if it's legal as long as you have some idea what you're doing. I'm simply trying to help with the latter.
     
  9. nrpetersen

    nrpetersen Line Up and Wait

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    Sorry guys, I'm with Tom on this one too. The air intake of any airplane engine is a kinda critical item subject to a lot of vibration, so I'd hope that there would be a lot of other ones just like mine to distribute the failure experiences.

    As a mechanical engineer, every time I've tried an aluminum weldment in a stressed application, I've been burned. There's a reason aluminum airplanes are not welded.
     
  10. Tom-D

    Tom-D Taxi to Parking

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    OMG don't try to teach on this web page, they'll accuse you of trolling.
     
  11. Tom-D

    Tom-D Taxi to Parking

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    OBTW, I forgot to ask, how would you know if that casting was an aluminum one or a Mag one?

    Would you care?
     
  12. tehmightypirate

    tehmightypirate Line Up and Wait

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    You're right, my bad.:goofy::goofy::goofy:
     
  13. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    Oh....you'll figure it out.;)
     
  14. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Hey, Tom, at least I didn't have an angry old A&P glue my oil filter on. Now THAT would certainly be an unapproved repair worthy of a call to the FSDO. :goofy:

    (I'll never let you live down doing that to a customer, especially when you're playing holier than though to others)
     
  15. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Umm...you know...it's not like this is a structural part.

    I'm curious, do you know what my carb heat box even looks like? Do you know what would happen if it cracked again? What if anything would actually come apart? What might jam? What might malfunction?

    Here's a hint. The box had three very significant cracks in it when I bought the plane. Everything still worked just fine. The carb heat still operated normally. The entire assembly isn't going to fall off the engine and out the bottom of the cowling if one of the cracks redevelops adjacent to one of the three the welds. It just ain't gonna happen.

    And none of the cracks has redeveloped after 12 years...much less all three of them...even though we all know that aluminum can't be successfully welded.:rolleyes:

    Okay, fine, I agree, aluminum can't be welded. It's impossible. My 182 is living proof of this and I have fallen out of the sky 15 times in those 12 years because of these welds. I admit, I'm not telling the whole story.

    Now back to your regularly scheduled programming.

    I'm going to the airport to glue on my oil filter now, just like Tom taught me how.
     
  16. Tom-D

    Tom-D Taxi to Parking

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    Tim, only you would defend a dead beat customer who got what they deserved.
     
  17. N801BH

    N801BH Touchdown! Greaser! Gone West

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    NO matter how ILLEGAL a A&P / IA's action was.......

    That Tom is a piece of work....:rolleyes::rolleyes:......:D
     
  18. Tom-D

    Tom-D Taxi to Parking

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    There ya go, off the deep end again, no one has said that aluminum can't be welded.

    It's the gaining the authorization to do it that is a bit difficult. Having the tools and equipment isn't in very many tool boxes either.
    But there is always one in a million that has a success at it. You must have had Henning weld it for ya.
     
  19. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    Tim....I had one a part last year. It went back together with rivets....:)
     
  20. Alexb2000

    Alexb2000 En-Route

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    Just for conversation and for some reading for those interested, here is a link to a guy that I trained with - Kent White. He does all kinds of aircraft repairs and including WELDING sheet. Here are some examples of his work that include welding airframe Al sheet:

    P-51 wing root repair including welding 5052-T3

    https://www.tinmantech.com/articles/repairing-wing-root-fairing.php

    P-51D wing tip fabrication including welding

    https://www.tinmantech.com/articles/making-an-airplane-wing-tip.php

    Here is an article he wrote discussing aircraft sheet welding applications and technique:

    https://www.tinmantech.com/html/aluminum_welding_article.php

    He did a lot of the complicated shapes like the wing root fairings on the reproduced Jim Wright Hughes Air Racer. He has produced U2 parts for Lockheed Martin.

    Etc.

    Point is it is being done all the time using basic equipment like oxy-acetylene.

    You just have to understand the limitations, like anything else.
     
  21. N801BH

    N801BH Touchdown! Greaser! Gone West

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    I spent at least an hour looking over that plane at Osh and drooled over the outstanding metalwork on it... That plane was PERFECT.....

    I fly back home to Jackson Hole and a day later I get call from a ranger in Yellowstone asking if I would recover a crashed plane 40 miles from my house.....

    When I found out it was the Hughes racer replica, I literally had tears in my eyes for hours..:sad::sad::sad::sad::sad::sad:


    So SAD.....:redface::redface:
     
  22. Alexb2000

    Alexb2000 En-Route

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    It really was perfect, better than the original. For example the wing root fairings on the original were three pieces if I remember correctly and Kent did them in one.

    That crash was an absolute tragedy. I've though a lot about the ironies of a modern reproduction with 60 years of technology advancement crashing, while the original didn't. Jim Wright was a big loss to aviation.
     
  23. Tom-D

    Tom-D Taxi to Parking

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    And he knows how to deal with dead beat customers. :)
     
  24. bluerooster

    bluerooster Pattern Altitude

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    But they are cast, which is a whole 'nother process.

    I would think that sheet AL can be welded pretty easily, following the proper procedure. And I don't think it requires millions of AMUs worth of equipement to do it.

    Some alloys can be clamped together and sewn up. Others require that you wait untill yer Ol' Lady has gone shoppin', before you can weld them. (she gets mad when you use the oven for baking aluminum parts)

    As to what alloy the box in question is. Just a WAG but probably 2024-T3.
     
  25. Tom-D

    Tom-D Taxi to Parking

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    Question is simple, where will you gain authority to do it when it was riveted, during assembly at Cessna. And Cessna's structural repair manual does not show it as an authorized repair?
    FSDO isn't going to give you a field approval, any DER/DAR isn't going to approve it either.

    See that T-3, what does that mean? can most A&Ps in the field duplicate that ?
     
  26. overdrive148

    overdrive148 En-Route

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    What, when did this happen? Man I'm not here enough :eek:
     
  27. bluerooster

    bluerooster Pattern Altitude

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    You probably can't get authorization to do it.

    T-3= solution heat treated and cold worked.
    I would think that for small parts the process could be done in the field by someone with the needed metalurgical knowledge.

    But that's not the point of the OP. His point is (from what I gather) that he carried his carb heat box to a shop where there was a qualified welder, with the knowledge and skillset to make the repair.
    Not some Joe Blow working from the back of a pinto (with four bald tires, and a brown door) on the ramp. And it's held up for many years.
     
  28. Tom-D

    Tom-D Taxi to Parking

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    And, at the next annual, the IA is going to ask, " who did this" then what's the answer?
     
  29. Dav8or

    Dav8or Final Approach

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    This thread perfectly illustrates why the E/AB category is the only bright spot in GA and why we need a new category for people to elect to decertify their certified airplanes and enjoy all the same freedoms those with kit planes have.

    The guy had his air box welded, he saved a bunch of money and it worked. The worst that could have happened to him was it would crack again and his time and money would be wasted on this repair. He performed a low risk experiment and it paid off. Sadly, the feds could likely write up a 300 page document explaining how terrible this repair is and how many regs it violates.

    :mad2:
     
  30. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Amen.

    Been through 11 or 12 annuals with 4 or 5 IAs and never been questioned.

    Next.
     
  31. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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  32. nrpetersen

    nrpetersen Line Up and Wait

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    You are not going to cold work a finished welded product. Post heat treat cold working can only be done on bar, plate and sheet stock only because of the forces etc involved.

    This part failed presumeably because of the vibration environment. The weld repair worked and I suppose it would be ok as long assuming somebody is watching for the possibility of a repeated failure. But what about the next guy that owns the airplane? or the new guy that annuals it? There is a reason for the approval trail in certificated aircraft, just as there is an experimental category that allows non-standard repair processes. One also has to look really hard at why did the original part fail.

    On the other hand, how many 4 cyl Lycomings have broken generator/alternator brackets......!:dunno:
     
  33. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Not just Lycomings. Continentals also. Mine broke last year. It's an STC'ed aftermarket alternator kit. We found it when we finally isolated and fixed a small oil leak.

    The A&P welded it.

    :goofy:

    :yes:
     
  34. Clark1961

    Clark1961 Touchdown! Greaser!

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    It'll crack again unless material was added...welding fatigue cracks is a ****-poor fix...we've all done it but that doesn't change the quality of the repair.
     
  35. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Not sure exactly how he prepped and/or finished up. I wasn't there.

    It lasted 51 years the first time...if it goes another 20 to 25, like I expect my carb box to, then I'll be happy. ;)

    Seriously, you bring up a good point though. Next time I'm changing the oil, and have the cowling off, I'll take a closer look. It may be worth fabricating a new part. This crack redeveloping would be a tad more of a concern than one in the carb box.
     
  36. Clark1961

    Clark1961 Touchdown! Greaser!

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    Good idea to keep an eye on it because fatigue is cumulative and not relieved outside the heat-affected zone. What's worse is the weld could have created stress risers which would cause rapid failure in the fatiguing environment. I'm not specifically picking on your A&P on the stress risers but I still find undercut welds on field repairs...

    On the cumulative fatigue part for the not-so-technical reader - what that means is that once a part has reached it's fatigue limit it will fail again in a short period of time if that part is repaired and placed back in service in it's original form and condition. There are some repair steps that perhaps can reduce fatigue but they aren't common in field repairs for the most part.
     
  37. Tom-D

    Tom-D Taxi to Parking

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    TCM engines have a gear driven gen/alt that are mounted on the rear of the accessory case. no brackets.
     
  38. Tom-D

    Tom-D Taxi to Parking

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    Aren't those steel?
     
  39. timwinters

    timwinters Ejection Handle Pulled PoA Supporter

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    Not this one. It's a belt driven aftermarket alternator that was STC'ed and installed way back...I don't recall the exact year...but a long time ago.
     
  40. Tom-D

    Tom-D Taxi to Parking

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    That would be an after market alternator for the 0-300-A and run off a pulley behind the prop. And yes they do break.

    But they are steel brackets