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Sheet Metal guys, I need some help with these door skins.

Discussion in 'The Hokey Ass Message Board' started by tlmartin84, Sep 2, 2013.

  1. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Dont even know why I'm still attempting to help, but here goes. The "stress" was already there, and when you tacked it, instead of taking steps to counter it, you increased it. The problem is two-fold. First off, as you were tacking, you went too fast between tacks, and didnt let the heat come out enough between welds, so by the time you got to the end, the panels were pushing away from each other, widening the gap you were spot welding. The clamps wont prevent this from happening. You can actually watch it happen if you are taking your time, after a few tacks, you can sight down the gap between the two panels, and see it opening up along the panel. If you stop welding and wait a bit, and as the heat comes out, you can actually watch the gap close itself up again. If you just keep throwing down more tacks you will lock the ever widening gap in place. Also, as others have said, you should have hammer and dollied the tacks/weld seam as you worked across the door, this will counter the tendency of the crown in the panel to pull in, and it will also FORCE you to slow down on the tacks. When you are welding sheet metal like this, you arent just distorting it in one direction, you are distorting it in both planes at the same time, if you dont take steps to counter that, you end up with a fucked up panel.
     
  2. Hammer on dolly the gray panel...it will come up....best way to hammer welds..planish..is gas welding...mig is too hard ..brittle...doesnt work best...tig is ok..softer rod..can planish...
     
  3. F&J
    Joined: Apr 5, 2007
    Posts: 13,217

    F&J
    Member

    Does not matter, we get it.

    As was said in many ways; when sheetmetal is die formed, there are unseen stresses in that piece, all variying in different places in the part. When you cut through a panel, even if done cold, the two halves won't be able to maintain their original contours.



    as a person gains experience, he chooses the "best" place for a patch panel, going to an area that will be less likely to go wrong. Example; many patch panels are very oversize for the typical rust problem on that particular car model. An experienced builder may choose to use just a small portion, and an unskilled person may not trim the patch at all, and cut a quarter panel way up, and get in trouble.
     
  4. I know exactly what you had.
    Upper larger section went in to the inner structure,
    The lower smaller side went out away from the inner structure.
    The edges fit pretty nice but you could drive a semi thru the middle.
     
  5. Cold cutting, even on a full length or Beverly shear or tin snips stresses the metal.
    Ever wonder why shear drops are curled?
     
  6. cavman
    Joined: Mar 23, 2005
    Posts: 630

    cavman
    Member

    Just my 2 pennies worth......If you are sectioning the truck, why not leave the outer door skins off until you have made the body cut, and THEN weld them on the door structure. Only one welded seam then. And if I were you I would use more of the blue skin, and make the seem higher on the door, on the curved part. Not on the flat.
     
  7. tlmartin84
    Joined: Jul 28, 2011
    Posts: 768

    tlmartin84
    Member
    from WV

    I am leaving it tacked until I get the panels all aligned for the section. I plan to take the section out where I currently have it tacked so I just have one seam. I wish I had more of the blue but unfortunately that's all that was good enough to salvage.

    The P/O had the truck sandblasted.......That probably added to the effect on the door skin.

    Any of you guys have any good sheet metal books you could recommend. Something that not only covers how to, but the why as well?
     
  8. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    Being a bit biased...but The books Ron Fornier produced were good( I worked for Ron 20 years ago when he was writing the 2nd book) But the Covell books are also very good...also, if you go over to the metal meet site, and lurk around and read, you can probably learn as much as reading the books...just my 2 C....Shawn
     
  9. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Mindovers (Hamber) DVD is also excellent, helped me a lot.
     
  10. ebfabman
    Joined: Mar 10, 2009
    Posts: 652

    ebfabman

    Make some braces the shape of the door, one inch wide brake 90 shrink one side to shape. always make several templates so you can have a reference of the shape. Cut the tacks, install the braces from the inside to hold the shape then figure out how you're gonna make up for the gap. May have to add a strip. Still going to be a tough job no matter what you do at this point. As been said next time go for no gap and a real even fit. You can still use the braces to hold the shape. You can cut them out or leave them in depending on how you make them. Got access to a shrinker stretcher?
     
  11. merc-o-madness
    Joined: Aug 23, 2004
    Posts: 1,544

    merc-o-madness
    Member

    i might be wrong but i think when these are stamped theres always that tension and it being together is the only thing that keeps it in shape, and once you cut it the tension made it pop
     
  12. No reason to have a seam, unless your door was rotted further up than the section amount. Separate the skin from the door up to the point where you are going to take out your section. Cut the door frame, remove your section, and slide it up. Cut off the skin at the bottom and fold back over the flange. Piece of cake!

    Other advise..Never weld in a patch that doesn't fit. It should set in place without any force whatsoever. Now your fighting the shrinkage compounded by the stresses that were there before you welded. The expansion and contraction is pretty predictable if everything is "happy" before you start. If not, then it gets even more difficult to diagnose exactly what has happened.

    And CLEAN your shit up!! Why in the world do people work with rusty crusty painted metal??? Your making this way harder than it needs to be!:D
     
  13. I'd just put a whole new one piece skin on it.
    Problem solved.
     
  14. tlmartin84
    Joined: Jul 28, 2011
    Posts: 768

    tlmartin84
    Member
    from WV

    I wish someone made a one piece skin for the F100s........


    That is what I wanted to do, but there was just too much rot
     
  15. Did you use the entire door bottom from the blue doors,
    Joining the inner structures just a little off, just a tiny bit will throw of the skins.

    Now the blue outer skin would be very very simple to make as tall as you wanted below that notch, then it takes more work.
     
  16. tlmartin84
    Joined: Jul 28, 2011
    Posts: 768

    tlmartin84
    Member
    from WV

    Not the entire bottom, actually none of it was from the bottom. The skin portion was from the upper part of the blue door. The problem is in the gray panel. I spent some more time looking at it and I believe the warpage was from blasting and the gray panel has been stretched.

    I found an oil can spot about the size of a saucer 6" diameter further up the door after spending some more time with it, the edge is probably 3" or so above my seam. It takes some force to get it to pop in or out which I guess is why I didnt notice it before.

    What I would like to do is have a replacement skin for the ENTIRE door, if anyone knows of any please let me know. I could make on pretty easily by tracing the edges onto some posterboard and transferring it to sheet metal but I don't think I can get the crown in it???? It would just be flat, anyone got any ideas?

    The other option I guess is to start up top and try to get it straightened out and work my way down the door.

    For now I am leaving it be until I get the cab where I want it.
     
  17. tlmartin84
    Joined: Jul 28, 2011
    Posts: 768

    tlmartin84
    Member
    from WV

    Just to give you some more insight as to what I am dealing with, here is what the P/O did to the top of the cab.

    [​IMG]

    I am beginning to wish I had just bought a nice clean one from the desert.
     
  18. cavman
    Joined: Mar 23, 2005
    Posts: 630

    cavman
    Member

    I think you answered your own question as to why the grey panel rolls in......the PO sandblasted it. Maybe try one of those "shrinking" discs on it.......
     
  19. ebfabman
    Joined: Mar 10, 2009
    Posts: 652

    ebfabman

    What I would like to do is have a replacement skin for the ENTIRE door, if anyone knows of any please let me know. I could make on pretty easily by tracing the edges onto some posterboard and transferring it to sheet metal but I don't think I can get the crown in it???? It would just be flat, anyone got any ideas?




    English wheel
     
  20. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    Look for some tip's here for shrinking some of those spots....http://metalmeet.com/forum/forumdisplay.php?f=167.....there are lots of tip's & tutorials on this site. Many there have started with worse....that is very repairable, it just takes time, especially if you are just learning....you will make mistakes & /errors in your thought process on how to fix things...but these are the best lessons, because YOU found what works best for YOUR skill set & tool library...A lot of people start with very basic hand tools, and do quite well...don't get hung up on having to have an e-wheel , or planishing hammer....hammer dolly , sand or shot bag, stumps, shop made shrinking disc, assorted hammers/dollies, A cheap shrinker /strecher is a good add, that I would recommend.Like I mentioned in a previous post, go lurk on some metal shaping forums, there is a lot of talented people sharing there knowledge...Shawn
     
  21. Flop
    Joined: Jun 8, 2006
    Posts: 3,885

    Flop
    Member

    man that gap has gotta go ! you are going to fight that mig welder the whole way accross that panel ...and dont say the camera makes it look bigger . its way to big to get a good weld on and a very hard to weld to begin with on a low crown panel . as the panel sucked in from the tacks the gap widened the whole way across . cut the tacks bring the panels back up to where they are supposed to be and get ready for alot of hammering .
     

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