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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. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    Here is what I did, and my dilemma.

    I salvaged skins off of an old set of doors I had to use as the lower skins for these doors. After redoing the bottoms I moved to the skins, when I cut the old skin into I notice it immediately roll in like the straightedge shows (gray skin). When I placed the Blue skin it set about 1/2" higher. I blocked the gray skin up from the back flush with the blue one and placed buttweld clamps and started spot welding. When I pulled my blocks and clamps it rolled back in.

    So how do I fix this? Leave it alone and fill it? Block it and weld it solid before removing the blocks?

    Note: I will be sectioning the door so I can redo anything I have done.....

    [​IMG]
    [​IMG]
    [​IMG]

    Sets good at edges....

    [​IMG]

    Rolled in at center.....

    [​IMG]
    [​IMG]

    Should I be doing anything with the interior rust, all I am doing is knocking the loose stuff off at the skins and any areas needing welded with a flap disc???

    After this door was blasted the backs of the skins have some swiss cheese on the folds. Do you all leave this alone or cut it out and replace it???
    [​IMG]
     
  2. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    OK...just a couple quick things...0ne , take more care in fitting the panel..ideal world, no gap...2 you need to hammer and dolly the tack welds you have put on there. the weld is shrinking as it cools (puckering the panel) and you need to strech it back out by hammering the welds ...you will need to take your time and tack & hammer until the whole seam has tack 1/2" to 3/4" apart, then weld between one set , hammer, move down 3-4 tacks, weld between a set , hammer, skip, weld hammer, until you reach the other side, then start back where you began , until the panel is fully welded. A tight fitting seam is THE key, as there will be less shrinkage...hope this helps...Shawn
     
  3. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    X2. It may not seem like it is doing anything as you go, but it does.

    The job you are doing, takes either skill, or experience, or huge b...s :)

    Try to get it straigtened out more before doing any more tacking.
     
  4. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Let me guess, you started your tacks on the right in the first photo, and worked your way across, right?
    You had the panel fitted nice and tight when you started, but when you finished, it wasn't fitted as well as you thought? Am I on the right track here?
     

  5. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    Did you all read my post??? It didnt come from welding, it is not oil canning from heat.

    The gap is 1/16 all the way, camera makes it look like its not, except for the area the cutoff got away from me. I use a 3/64 wheel, fit the panels together tight then run the wheel down the seam to open it for my clamps.

    The original door rolled in as soon as it was cut. It was like it had tension on it. I hoped i could just push it back up to match the blue one but that was not the case.

    Posted using the Full Custom H.A.M.B. App!
     
  6. The only thing I like to add here is try to keep the area surrounding the tacs as cool as possible. There are home remedies and products out there that were made for such applications. I use the material from Eastwood when I tac welded the lower quarters of my 1963 Impala. In my case I was lucky the joint was under the lower molding so I plug welded the two skins together. Nevertheless, the joint came out straight. Also, follow the advice from shawnspeed. Good luck
     
  7. falconsprint63
    Joined: May 17, 2007
    Posts: 2,358

    falconsprint63
    Member
    from Mayberry

    i'll also add that yes you should be doing something to the rust inside or it will come back to bite you. at bare minimum knock it down with 80 grit or so (even better if you blast it) then spray it with a rust inhibitor and then get some sort of top coat on it. rustoleum on the cheap or por 15 on the spendy. perfect world replace all the swiss cheese metal.
     
  8. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    If you don't stretch the welds, that roll will get worse.

    Yes, even those few welds you have now, have set up more tension in the skin.





    I'm really lost...if you plan to section the door later, then why are you welding it up now?
     

  9. I use but clamps all the time. If you tig then no gap is better but if you use mig then a little gap is good ( 1/16") so when you grind weld down you don't grind weld off. then you do exactly what shawn has stated above!!! Work slow as to not get to much heat and hammer the seam as you go and the shrinkage will straighten out. Just DONT HURRY!!!!
     
  10. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Sorry, I guess you dont need any help, forget I said anything...:rolleyes:
     
  11. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    If i cut the tacks now, the blue would pop up amd the gray would roll down. Like it did before i started. Maybe i should cut them loose and spend some time on the gray panel trying to get what stress is in it out??

    The bottom of my cab is shot, and i am putting a custom floor in it. I am tacking the doors up so i can get all of my panels in place and true prior to sectioning it.

    Posted using the Full Custom H.A.M.B. App!
     
  12. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    Well, not all of the builders here would do it that way...but..

    Since you only need to tack, to make 2 doors good enough to fix the entire cab first...then I suggest you stop messing with that "roll" for now.

    Get the two doors fitted up good enogh to test fit to the rusted out cab. Once you are confident that the doors can be used to get the cab rot fixed into the correct measurements, then worry about the skins after the cab rot is done, and then sectioned, ...... then mess with the doors.
     
  13. good read guys.....
     
  14. Highway 41
    Joined: Jan 31, 2012
    Posts: 13

    Highway 41
    Member
    from Georgia

    Been doing 50's and 60 's ford trucks for a long time and unless you do as some others have suggested and hammer the welds as you go this will always happen. I use soft mig wire and try to hammer the welds while they are still hot. I still do not get it as straight as I would like and have to do a little torch work to stretch the metal a little. Good Luck
     
  15. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    You all are still missing it. The dip was there before i STARTED.

    Try to picture the straightedge as is. When i started the blue panel was flush with it. The gray panel was way low. I pushed it up and held it and tacked. I thought it would stay and they just rolled in. THIS IS NOT OIL CANNING FROM HEAT.

    do you think a full weld would hold it?

    Posted using the Full Custom H.A.M.B. App!
     
  16. Cutting thru the crown is what did it
    For an example, cut a square and shrink the edges. You'll have a nice gentile crown in the panel. Now cut it thru the center, it will be just like your door.

    If we don't get it , try explaining what you want the answer to again.
    Cutting causes shrink too,
     
  17. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    What 31 Vicki said is true....and by hammering the welds(and inadvertently the surrounding sheet metal)you will strech the metal that is causing your problem and "fix" it all in one fell swoop..:eek:...sorry I did not explain enough in my original post....now you can fix it when section your doors...I never did like the clamps that left the gap...always fit my panels tight , and tig or gas welded them...have done them with mig and the same process...Shawn
     
  18. MP&C
    Joined: Jan 11, 2008
    Posts: 2,477

    MP&C
    Member

    When the door skin is pressed from the factory, you have much more crown at the center than along the edges of the skin. So once you cut through the center of the skin, you now have those "panel crown" stresses right at the edge of your cut, hence it pulling downward.

    On to the shrinking that was mentioned earlier, if you don't start planishing the welds, the panel along the weld will continue to sink in, forming a valley. Think of an arc (the panel's crown) and when it shrinks, it forms more of a straight line, thus pulling the weld inward.

    With the cut edge pulling inward and the weld shrinking compounding the issue, you need to hammer and dolly the welds to help get the weld seam stretched back out and restore the crown to the panel..
     
  19. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    I don't think so :)

    This ain't their first pony ride when talking about failure to stretch welds or spotwelds in a panel like that.



    A full weld with no dolly stretching will leave you with something that will look "different"...but take your own path.



    I took some pics of a dead flat hood side from the 20s. I made a big patch piece, and wanted to show the effect of just ONE quick mig tack, on the perfectly aligned patch which was CLAMPED. It went out of alignment, and some gaps were gone.

    Then I took a pic after just ONE dollied smack of that single spotweld, and how the now-unclamped patch was back to perfect alignment.

    You keep saying those tacks are not a problem, but many of us do.
     
    Last edited: Sep 2, 2013
  20. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    Thanks, that I understand that MPC. How come the blue panels held their crown and the gray ones popped in?

    It was bowed down when I placed the butt clamps, and I blocked it up to hold it where it should be. If I hammer it the spot welds I know it will help and stretch the metal, but I don't think it will be enough and the dip will stay.

    If I hammer the welds and weld it solid and it is still there, how do I go about pulling it up after it has been welded solid?
     
  21. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    MISSING IT........as in missing the fact the panels were rolled in here to start with, with just the buttweld clamps in place before a welder even touched it. The cutoff disc generates heat I know but not enough to cause this thing to bow in the way it did.

    I think MP&C explained it.
     
  22. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    No one has said it was oil-canning from heat, but you dont seem to be interested in hearing anything that conflicts with whatever idea it is that you already have in your head. So dont keep us guessing, you tell US what the answer is, I for one, will be happy to pat you on the back and agree. Hell, its not MY door...:rolleyes::p
     
  23. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    As far as a "full weld" I mean fully spot welded and hammered/planished. Not a solid bead.

    do you think the full length weld will hold the stresses or pop back in.

    I am asking now before it is time to weld it solid and I have a caved in area I can't fix.
     
  24. MP&C
    Joined: Jan 11, 2008
    Posts: 2,477

    MP&C
    Member


    Probably because the upper skin is starting to transition into the roll at the top of the panel, and the lower skin has the stresses a bit different because of the different shape.

    Planish the welds to provide the stretch. While you're planishing weld "dots", don't worry about getting it all fixed at that point. Add some stretch, grind the dots down to make room for the next welds, and repeat. Once all welding is done, then you can continue to planish and better read the panels reaction to your efforts. At some point you will start to get close to the stretch you need, where you'll likely start to see a loose oil can flop. Now you need just a bit more, until it holds the shape. I'll add that most of your stretching will be hammer outside, dolly inside. When you get towards the latter stages of this effort, it may help to change to hammer inside, and a lead shot bag outside. This still provides a small amount of stretch but also better persuades the panel outward where it needs to be.
     
    Last edited: Sep 2, 2013
  25. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    What he said^^^^.....which is basically what we have been telling you....and you would have to do alot to that door not to be able to fix it without just hammer & dolly work as has been described...you will just have to do more of it to get it there..Shawn
     
  26. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    So planish as I go (which is what I am/will do). Then at the end (if it isn't flush) planish it more along the seam and that should pop it out.

    Thank you.
     
  27. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    YES....be careful not to over work one area...keep it even...Shawn
     
  28. You are seeing it , yet not believing it.
    That edge where you cut it got hot, really really fucking hot actually.
    The heat affected zone is small , so not a big area was shrunk, just the edge.
    Think about pulling a thread on an edge of fabric, it's only one thread but it will screw the lay of the entire piece up.

    Shrinking mini amounts thru the crown will have a large effect,

    Now how to fix it, when you section it, take it out of both sides of this joint.
     
  29. tlmartin84
    Joined: Jul 28, 2011
    Posts: 1,030

    tlmartin84
    Member
    from WV

    I wish I would have had a picture of it prior to tacking.

    I was not trying to argue with you guys, I understand why you hammer and dolly welds. It just when I first put the panels together and I saw a gap you can stick your fingers in I began to question if there was something else at work here.
     
  30. spiders web
    Joined: Jan 16, 2011
    Posts: 387

    spiders web
    Member

    I have encountered a similar problem and I hammer welded the beads. When finished I still had a low spot. I dimpled from the back the entire weld area to now have a hump at the weld. I then went after it with a shrinking disc and it smoothed out the panel while tightening the metal so no oil canning occurred. Move on citizens, there is nothing left here to see!!!!!!!!
     

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