Preventing metal warping

  1. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester
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    I plan to join these together and then cut to right shape.
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    so I've got a need to weld a repair piece to a glove box for my scooter (as I've messed up and cut it down too much). As its thin sheet I'm practising first on scrap and I'm cornerned that it will warp

    Having read the guide on here about thin metal I've tacked my two practice stripes together and then welding short strips at opposite ends. I'm also cooling with a damp rag the area next to my weld on both sides after finishing each strip.

    Ignoring the lack of penetration for now, I still find it warps.

    I've 4 ideas as to why that might be but I thought I'd get some feedback first before trying again

    1. Wait longer before moving on to next strip at other end

    2. The size of the strips im using to practice are not helping ( thin and long)

    3. I'm cooling in the wrong place and making it worse?

    4. The way I'm clamping to one side is not helping
     
  2. Gritineye Forum Supporter

    Messages:
    1,039
    Sussex UK
    Have a look at Trevs blog here:

    He talks a lot but worth listening, he gets good results using simple methods that anyone can follow.

    The actual welding starts about 30:00
     
  3. Kent

    Kent Member

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    Bowland, Lanacshire,UK
    You won't manage that . I should do a joggle bend a few plug welds and fifillfifilll .
    Can it be done ? Yes but only with much skill practice and a big chill block , way too much a challenge as yet ! The above should get you the place you can live with in one hit
     
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  4. fixerupper

    fixerupper Member

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    EdB ... try doing a series of individual spot welds about 2 inches / 50 mm apart using one hand on the trigger and your other gloved hand to position and steady the torch. Use your clamps to hold the steel together along the intended weld line with a bit of flat copper pipe as a heat sink ...When you get the two bits held together along the full length let it cool then add a weld in the gap ,so you end up with a tiny spot weld at every inch don't be tempted to run a bead just keep adding in the gaps until you are happy with it ..
     
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  5. optima21 Forum Supporter

    Messages:
    2,705
    Location:
    halifax, England
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  6. fixerupper

    fixerupper Member

    Messages:
    1,517
    Location:
    Crete Greece
    It's hard to see from your photo but the repair you are doing looks like it has complex curves . Is it structural if its not could you tack it on and finish with filler? I think you should make the piece you need to add to your scooter , then fit it on .. rather than weld steel on and then try and cut it to shape once it is welded on .
     
  7. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester
    There is no curve in the bit I'm doing - the only curve being the shape I'm planning to cut into the metal. My reasoning in cutting after welding the metal to glovebox was that I was wanting to avoid welding a sharp point where the two pieces of metal meet which I thought would be far too hard to not melt. I hope that makes sense. I can upload a picture of the shape I'm planning to cut the metal too if not.


    Its not structural which is why I'm not particularly bothered about penetration. the edge will have a rubber fitted that cushions it against the leg shields. The difficulty with tacking and filler is that I've powder coated the scooter (to save money) and you cant use filler. However I've used a RAL code so I could purchase a spray can and respray it myself, once I've stripped the powder coat (which would be a pain or I'd need to get it sand blasted again). Something I will think about

    joggle bend? If it really is so hard, there is the option to outsource it to someone local who runs a bike shop and its a good welder, but will obvs cost me but I am willing to consider this.

    Thanks. I was doing small spots but maybe yes more 'spotty' and further apart and more time inbetween..I was hoping the top of my welding table which looks to be copper (maybe) might act as a heat sink (altough this wouldnt help with my eventual weld)

    Thanks I'll have a look as soon as poss...
     
  8. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester
    Thanks. I'll try and watch all that when I get the time :)
     
  9. Screwdriver

    Screwdriver Member

    Messages:
    5,377
    UK London
    Let me save you an hour of your life: use a wet towel along the edge, join the dots.

    I don't know this chap or how well respected he may be but I wouldn't be happy if I got the results he shows here. Sorry Trev.
     
  10. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester
    Interesting post (an impressive work). I notice that you used the intergrips to maintain a gap between the two pieces of metal. I purchased some of these thinking these would be of use for this project but when I tried using them on a practise piece I just blew holes all over the place with 1mm sheet. Were you using thicker metal on your car?
     
  11. optima21 Forum Supporter

    Messages:
    2,705
    Location:
    halifax, England
    Ive just done this with 0.8mm zintec, but ground off the zinc coating first, using 0.6mm wire and argoshield light gas

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    and then ground down

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    there is definately some distortion there, but its not too bad and you can't expect it to be perfect. I could have done with a bit more penetration in some areas though as this is the reverse side

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    its just practice that we need, I only do occasional welding so its not too hard once you get the hang of it, although I'd love to be able to produce some of the quality work of the guys on here who really do know what they're doing.
     
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  12. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester
    Thanks. I think I'll keep trying for now and see if I can improve
     
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  13. fixerupper

    fixerupper Member

    Messages:
    1,517
    Location:
    Crete Greece
    I watched the bid until he cut mig wire with a pair of tin snips. My pet hate.....tin snips are for sheet tin copper or brass never wire ....use side cutters .....
     
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  14. Cobbler

    Cobbler Codger bodger

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    Location:
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    I lost the will to live after about 1 minute, on about all his tricks multiple times. & turned it off.
     
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  15. MattH

    MattH Member

    Messages:
    3,652
    Location:
    Bristol
    If you can get to both sides of the joint the why not alternate every weld to each side of the piece thereby negating a lot of the distortion?
    Most of the guides posted up are for bodywork with only one side available.
     
    Ed B likes this.
  16. Ed B

    Ed B Member

    Messages:
    82
    Location:
    Manchester

    Yes I will be able to get to both sides for this. Would you think alternating in the same area would be best approach or randomly in different locations..


    Started on another attempt, about half way through, its already warped a bit but more into a 'V' shape at the join rather than just randomly, which I guess is progress :) One thing that did make me laugh was I decided to give the intergrips another go and finding out its quite difficult to remove them once I'd done four tacks
     
  17. optima21 Forum Supporter

    Messages:
    2,705
    Location:
    halifax, England
    yeah thats because the metal shrinks as it cools, if you want to increas the gap between the two panels and have access to the back for a dolly you can hammer onto the tack. if its starting to "V" while being tacked, its best to try and staighten the two sections then.
     
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  18. Gritineye Forum Supporter

    Messages:
    1,039
    Sussex UK
    But I did warn you, and told you when the welding started :D
     
  19. atomant48

    atomant48 Member

    Messages:
    777
    Salisbury UK
    I had the pleasure of an hour in a hot rod / restoration shop earlier in the week made me think of this thread. Their work is inspirational. Sorry doesn’t help you but I guess it proves it is possible (maybe not for us mortals though!)
     
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  20. Morrisman

    Morrisman Forum Supporter

    Clamp it all rigid to some flat bar, with as many clamps as you can get in. Weld in very short sections, it won’t distort at all.
     
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