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Shrinking a roof skin .... Help please

Discussion in 'The Hokey Ass Message Board' started by 296 V8, Mar 6, 2013.

  1. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,666

    296 V8
    BANNED
    from Nor~Cal

    So how would you go about it ?
    I’m getting nowhere on this one / iv probably made it worse.

    Its had damage all around the front and part way down the sides.
    That stuff is all back in shape but I cant get the big flattish areas out in the center to tighten up / stop oil caning.

    Thanks in advance
    Greg
     
  2. Are you using a English wheel? HRP
     
  3. tbauer
    Joined: Jul 16, 2009
    Posts: 233

    tbauer
    Member

    Maybe it's just me but pictures would be helpful. Without seeing the problem it's hard to help. Send me a private message in case i don't see you post pics.
     
  4. big duece
    Joined: Jul 28, 2008
    Posts: 6,830

    big duece
    Member
    from kansas

    Hot water, and 40 minutes in the dryer.:D
     

  5. 1/2done
    Joined: Oct 29, 2006
    Posts: 628

    1/2done
    Member
    from Ohio

    How are you performing the shrinks? I had good luck with a shrinking disc and using a homemade slapper and dolly.
    [​IMG]
    [​IMG]
    [​IMG]
     
  6. big duece
    Joined: Jul 28, 2008
    Posts: 6,830

    big duece
    Member
    from kansas

    Holy crap, that looks awsome!
     
  7. Beautiful work. HRP
     
  8. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,659

    Rusty O'Toole
    Member

    Have you considered a vinyl top?

    Or, some pictures would help. Or even the model, make and year of the car and whether it is a stocker, hot rod or custom.
     
  9. pimpin paint
    Joined: May 31, 2005
    Posts: 4,937

    pimpin paint
    Member
    from so cal

    Hey Greg,

    It could well be that " the big flattish areas out in the center " are not in need of shrinking, but are being held under tension or pressure:eek: If the damaged areas at the front or side of the roof wern't bumped and finished correctly , you could well have this condition!
    A before photo of the damage could serve as a ''treasure map'' as to how best to get outa where you're at! A semi/low crowned panel, like a roof panel ,is nowhere to learn how to shrink metal especially if that roof panel is badly damaged:)

    " The ice cream truck in his neighboorhood plays Helter-Skelter "
     
  10. irondoctor
    Joined: Jan 7, 2007
    Posts: 568

    irondoctor
    Member
    from Newton, KS

    That is outstanding work 1/2Done!!!!!
     
  11. sanchtech
    Joined: Jan 4, 2013
    Posts: 17

    sanchtech
    Member
    from Sac, Ca

    are you sure you worked out all the damage before shrinking? Sometimes an oil can isn't created by the overall damage but a particular brow or imperfection, and once you get that particular one worked out it will tighten up. This is why doing good metal work before shrinking helps. But let me be clear, I do your traditional style bodywork and mudless repairs are something I have never had time for in a shop, so take my answer for a grain of salt. Will say though, the shrinking disk will work well with that after you used a good flat plastic mallet/sand bag. there's also other things to consider. The shape is an oval so if you take a spoon in the corner you can tighten it up as well. This works great on hoods where there's a peak bodyline in the middle. You can run a spoon parallel to that line in the middle of the hood and tighten it up that way, but I always start from the corner but that's not where you start,that's just for tightening up a straight hood/roof. Might try hand blocking your sheet metal to get a full grasp of what you're dealing with first cause metal work is first and some of those oil cans might go away with the redistribution of metal
     
  12. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,666

    296 V8
    BANNED
    from Nor~Cal

    Well I was thinking I had the sides back out were they should be. Thinking about it this morning I was more inclined to believing the guy pounding on it before me went to far.
    But driving home today I was thinking of trying to spread the thing with the portapower and see what happens.
     
  13. Why don't you post some good pictures first. "Porta power & see what happens" worries me a bit :eek::D
     
  14. Shrinking a panel;
    With Oxy/Acety torch and small tip.
    Make a tight group of 3-5 dime sized, red hot spots on the high, flat area.
    Quick cool heated spots with a damp rag. Repeat as necessary.
    Do not over hammer, file, grind or stretch.
     
  15. BadLuck
    Joined: Jan 7, 2006
    Posts: 3,055

    BadLuck
    Member

    i had some similar problems on my roof and a fender on my 52... tried working it out.. just made things worse...i finally bought a shrinking disc... worked awesome..
     
  16. jvo
    Joined: Nov 11, 2008
    Posts: 268

    jvo
    ALLIANCE MEMBER

    Like the others said, post a pic and it will be easier to diagnose your problem. If you look at this thread, you will see a tool I built to simulate a dolly on the underside of the roof panel. It was too hard for me to reach out into the middle of the 40 tudor roof panel, and put any amount of upward pressure on the dolly. I built the tool, and it made the planishing of the roof panel really easy.
    It was slightly tedious to keep moving it around inside the car, but I was able to use a slapper on the top side and planish it out quite easily with the support tool. Next time I go to use it, I will build a "knuckle" on the bottom of the tool so it will sit on the uneven areas of the floor pan a little better. Good luck.
    http://www.metalmeet.com/forum/showthread.php?t=9867
     
  17. snopeks garage
    Joined: May 25, 2011
    Posts: 556

    snopeks garage
    Member
    from macomb MI

    BEAUTIFUL work!
     
  18. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,198

    fordcragar
    Member
    from Yakima WA.

    Post some pictures so we can see what you are doing. Taking a porta power to it, if none of the structure has moved would be going in a negative direction.
     
  19. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,666

    296 V8
    BANNED
    from Nor~Cal

    There's really nothing a photo is going to show
    The main body of this top is very flat. that’s the problem …. I could easily deal with a nice round thick 40’s roof all day long.

    I think we all know what a 12 to 14 inch bird bath looks like … iv got at least 4 that are ¼ to ½ inch or more deep

    Iv tried the heat and quench deal and just like every other time iv ever tried it (on a flat) that just makes it worse.

    Im going to make some suports / bows and call it done.
     
  20. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,780

    fleet-master
    Member


    Please don't do this yet Greg, if you can post up a couple pics that'd be good. Have you ever done hot shrinking on panels before?

    Its not just knowing how to shrink thats important but exactly WHERE and HOW BIG to make any shrinks. If you over shrink a panel it can be a lot of work to get it back where it needs to be.
    And my advice is to (almost)NEVER cool a shrink with a wet rag. A wet rag is great for stopping heat travelling out across a panel but thats all IMO.

    Again, please post some pics.
     
  21. oldrelics
    Joined: Apr 7, 2008
    Posts: 1,727

    oldrelics
    Member
    from Calgary

    The back cab panel on my '41 ford pickup was oil canning real bad....it is a very large low crown panel, and it had a combination of damage from years of impacts and rough sandblasting. I worked on it for weeks, VERY fustrating. I know exactly what your going thru. I used a shrinking tip on my unispotter (stud welder) and placed probably 200 shrinks to get it tight. The shrink tip heats a very small dot on the metal and is more controllable than when I used oxy-acet. Its alot of trial and error. It now is tight and should need no more than 1/8" filler and thats good enough for me. When it gets too fustrating, put it away until the next day (that saved me from cutting that cab into little pieces:eek:)
     
  22. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,780

    fleet-master
    Member

    Haha you must of been typing at same time as me Greg...:D can you spot where these areas are 'hinging'? If so you can poss planish these a bit to help lock the metal where you want it..
     
    Last edited: Mar 6, 2013
  23. e-tek
    Joined: Dec 19, 2007
    Posts: 424

    e-tek
    Member
    from SK, Canada




    Ok.......

    Well, if you don't want to take the most basic bit of advice, why ask at all?!?!? :rolleyes:


    Did someone ask for a definition of shrinking? Well this is not it:

    :rolleyes::rolleyes:
     
  24. The man ask for help.
     
  25. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,198

    fordcragar
    Member
    from Yakima WA.

    What I'm trying to visualize is how the damage might have been created; which you really haven't mentioned. There is a reason that you have the oil cans, were they always there since the damage occurred?

    With your heating and quench, you've probably done more damage.

    Do you know how the damage was created? Or give us an idea what it looked like before you started shrinking?
     
  26. And several guys stepped up to help, and asked for pictures. If it's not worth the OP's time to post pictures, why should we waste our time guessing.
     
  27. the year make and model would help to get a visual of the car's roof line at least
     
  28. most likley an off topic car
     
  29. black 62
    Joined: Jul 12, 2012
    Posts: 1,895

    black 62
    Member
    from arkansas

    frustrating and enlightening ---good info ---that top 1/2 done did gives me hope for a flock of 66 novas i have...
     
  30. Fenders
    Joined: Sep 8, 2007
    Posts: 3,921

    Fenders
    Member

    X2, the HAMB helps those who help themselves.....
     

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