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Technical Opinions on making a roadster doorskin

Discussion in 'The Hokey Ass Message Board' started by HRK-hotrods, Jul 24, 2016.

  1. HRK-hotrods
    Joined: Sep 26, 2007
    Posts: 922

    HRK-hotrods
    Member

    I'm going to be tackling my long term 29' Chevy roadster project soon. I'm looking for some opinions on a few ideas I had concerning the fabrication of the skin. I have a pair of very rough doors. The passenger door is straight but you can read through it. The driver door is solid but was literally ran over so it's pretty hurt. Chevy roadster doors aren't exactly falling off of trees and reproductions are not available. I am still working on building my English wheel which in my opinion would be the "correct" way to start off but with most things, there's more than one way to skin a cat.

    Is it possible to make a male die from oak with the proper crown and shape of the door and press it into a piece of 18 gauge using a shop press? I was thinking that I could bolt the metal over a frame and press the male die into the metal, effectively pressing/stretching the proper shape into it, where I could then use a female mold of the bead detail to flow form that into the skin... Make sense?

    I understand that using a wheeling machine would be the best way to shape the door. Just looking for some alternative ideas. Would it be possible to pull a duraglass mold backed with concrete off of the entire door to use a mold for flow forming?

    Here's a picture of one for reference.
    Screenshot_2016-07-24-21-01-06.png
     
    Last edited: Jul 24, 2016
  2. i have made body panels using parts from other vehicles. i cut a cardboard pattern of the "crown" and and walked around the junk yard for a match. for example: i used the top of a AD chevy pickup fender to fix the tail section of a 40 chevy coupe. i would bet a "skin" from a few 30's-50's doors would be a close match.
     
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  3. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,582

    Rusty O'Toole
    Member

    If it was mine I would cut away the bad part and make a lower door skin. As long as you stay below the top 6" where the molding is. Don't replace any more than you have to.

    Cut out the door skin to size and bend a 1/2" around the edge on a brake. Bend the folded edge over a 1/16" strip of steel. Curve the skin to match the door by bending it over an oxygen bottle or other handy round shaped object.

    Slide the skin up into place and carefully weld along the top seam. Flatten the edges down and tack in a couple of spots if necessary.

    You shouldn't need anything elaborate to form the shape as it is a simple curve.

    All this is standard body shop technology for an experienced metal man. The trickiest part is welding the new panel on without warpage, that is where the years of experience come in. And of course, on your car the door is framed with wood. If you are not confident in your skills it would be best to have the doors done by an experienced bodyman. They are too rare and too easy to mess up.
     
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  4. evintho
    Joined: May 28, 2007
    Posts: 1,783

    evintho
    ALLIANCE MEMBER

    Yep, it works! Made a cardboard template (pizzabox) of the crown of my '27 roadster bun panel. Took it with my to Pick-N-Pull and set it on every curved panel I could find. Finally settled on a late '80s Chevy van hood. Added some jambs and repro patch panels on the bottom. Viola! '27 bun panels! There's so much sheetmetal at the yard you're bound to find something that'll work!

    [​IMG]



    [​IMG]



    [​IMG]


    [​IMG]
     
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  5. HRK-hotrods
    Joined: Sep 26, 2007
    Posts: 922

    HRK-hotrods
    Member

    Thanks guys. I didn't think of that but we'll keep it as an option.

    @Rusty O'Toole , my doors are barely good enough for a pattern. You will notice that the top of the passenger door is missing in a few spots. I'm used to having access to the proper equipment but my dad sold his business 10 years ago when his health failed. I'm basically starting all over gathering my own metal shaping tools.
    137161-1260599068-cb78e4ec1b7bfbd1f0cf0e83b009a154.jpg
     
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  6. badshifter
    Joined: Apr 28, 2006
    Posts: 3,344

    badshifter
    Member

    Foming by pressing requires an unbelievably strong die, male and female, and the sheet metal blank needs to be held around the perimeter while being pressed to keep from just pulling/wrinkling. On a low crown part the die will need to have more crown than the finish part making an original piece too shallow to make a die from. Your in Jersey, gotta be plenty of guys near you that have even a cheap harbor freight English wheel to make a panel. If you have a pressure washer, lots of clamps, and body armor, Google hydro forming sheet metal at home......
     
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  7. inliner2318
    Joined: May 9, 2008
    Posts: 312

    inliner2318
    Member

    Contact delcar (Dave Langston). He made me a pair for a 29 Chevy roadsters I had. He does some great work!


    Sent from my iPhone using The H.A.M.B. mobile app
     
  8. F&J
    Joined: Apr 5, 2007
    Posts: 13,223

    F&J
    Member

    Like was said, the copying of the compound curves taken from a stock good door will make the new part a shallower crown, due to spring-back.

    ..and hydroforming at home is limited to much smaller parts as far as square footage. I did a techweek entry on hydroforming a 7.25" diameter hub cap skin, and the square footage times the 1500 PSI hyd pressure put the force on the 2+ dozen grade 8 bolts to around 60,000 to 80,000 pounds of "spreading load" on the die halves. The spreading force on a 2+ foot square door would be insane :)

    I'd go with donor skin from an older van side or pickup door and avoid the modern cars with the thin special hardness steel.

    I'd make any of the belt-line parts separate and weld them on. I did all that with my fake cabriolet doors.
    DSCN0412.JPG
     
  9. indyjps
    Joined: Feb 21, 2007
    Posts: 4,247

    indyjps
    Member

    Getting the wood to shape that large will take a lot of time. Unless you can hold the steel in place to get stretch in the panel, all you'll do is bend it and it will spring back.

    I vote for repairing the existing panel, or using a wheel to get some crown built in and adding flanges, I've seen tipping wheels used to get the flanges started but have never done it myself.
     
  10. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    I assume you are asking how to form a compound curve in a flat panel without an English wheel, right? Mark a grid pattern on the back of the panel. put it on top of a relatively thick piece of flat steel, like your welding table, and lightly hit the middle of each square with a low crown hammer. Then repeat on the intersection of the lines forming the grid pattern. Keep repeating this, and as the panel starts to crown, start hitting the areas on the original panel that have more crown more, and the parts that have less, well, less.
    Yes, its lots of work, but the fact that its slow going works to your advantage, its easy to see how things are progressing, and gives you more control.
     
    Last edited: Jul 27, 2016
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  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,053

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I agree with the above suggestions about sourcing your door panels from existing panels that have the right crown. '30s thru '60s era vehicles would be a good place to look. Not only would have the crown you need, but the correct metal, typically 19 ga draw quality, and forming the edges would be easier than with cold roll sheet stock.

    Also, I suggest you consider replacing the wood frame with a sheet metal frame. That is not so difficult as one may think at first blush. It would require some simple forms made from wood or MDF. I am not just suggesting this without a basis in experience. Some years ago I took several metal forming classes conducted by Ron Fournier and we made smaller versions (about 1/2 scale) of several larger parts, including a '40 Ford rear fender. But a roadster door was one of the exercises. I still have that door and will photograph it and post it here for you, and others, to see how well the process worked.

    Ray
     
    Last edited: Jul 27, 2016
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  12. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,053

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Here are some pics of parts made during the classes to illustrate the processes. These are aluminum, but the same the techniques apply to steel. The two small pieces, airfoil and nondescript part, were done with hammer form process using an MDF pattern. That pattern process entails two pieces, the actual form you want, and a slightly smaller of like shape to 'sandwich' the metal to be shaped. Also, the holes you see are for through bolts to maintain the alignment of the patterns and metal to be formed. That is important.

    The fender pictured, also of aluminum, was made using a wooden buck, not a hammer form. The buck defines the contours of the part(s) and is used to monitor the shaping process, which was done with mallets, shot bag and English wheel and post dollies. In the next post I will show the door pics and applicable comments.

    Edit: screwed up the loading of pics. :confused:....see next post...

    Ray
     
    Last edited: Jul 27, 2016
  13. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,053

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg

    well, it worked a little better this time....:)
     
    Last edited: Jul 27, 2016
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  14. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,053

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg
    Here are the door pics.......

    The sides and bottom were relatively easy to make with hammer form process. They basically consist of the wide part with flanges bent along the edge. You simply have to make the form with the vertical or horizontal curve that follows the body side profile. The same for the inner surface....or straight if that works best inside. Also, note that at right angle corners a small hole drilled at the corner, before notching the material for bending, produces a better fit without the little 'spur' that normally results.

    The perimeter of the skin has to be 'tipped' or bent 90* to begin the hem that holds the skin to the door frame. It might be best to get the skin sized, shaped and flanged before finalizing the door frame assembly so that the door skin and frame are a good fit. A bead rolling machine with 'tipping dies' works really well for that operation. The door frame bracing could be more elaborate, such as diagonal, for extra strength.

    The belt line is a bit more difficult. I agree that if you can salvage your existing belt line section, you might want to consider that, and weld it to the lower skin. Ideally, the belt line could be formed on a Pullmax or similar machine with homemade dies, but I think a hammer form might work for that as well, especially a female hammer form.

    In any case, I hope some of this proves useful and wish you the best with your Roadster project. If you have any questions I may be able to help with, just post them or PM me.

    Regards,
    Ray
     
    Last edited: Jul 27, 2016
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  15. toreadorxlt
    Joined: Feb 27, 2008
    Posts: 733

    toreadorxlt
    Member
    from Nashua, NH

    if you buy a harbor freight english wheel and use a low crown die, you can effectively make a door skin... The key is to make gauges (accurately cut cardboard) to quantify the amount of crown in the original panel... concentrate your passes in the center and work your way out until it satisfies the gauges.

    All an english wheel does is stretch.. add area.. as you add area, it has nowhere to go but up.. creating crown. Use the lowest crown anvil behind the flat one and overlap your passes.

    Get a coupon and you can likely get one for $199... I use big wheels all the time, but i know the HF can put shape into 19ga metal.
     
  16. F&J
    Joined: Apr 5, 2007
    Posts: 13,223

    F&J
    Member

    You made it look easy...the sides, I mean.

    The side pieces need that edge 90 to flange the door skin to, but those sides are curved to match the quarter, so the 90 can't be done on a brake...

    not sure how many tries I would have to do, before it worked :)
     
  17. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,053

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    You are correct, but as I said in my text, or thought I did, the sides were made on a hammer form pattern precisely for that reason. The sides can have as much, or little, curvature as needed. Both outer curve and, if need be, the inner profile of the door frame as well. Really, making the pattern is pretty easy, starting with a cardboard (poster board, not corrugated) pattern and transferring to MDF or wood.

    Ray
     
  18. HRK-hotrods
    Joined: Sep 26, 2007
    Posts: 922

    HRK-hotrods
    Member

    All great advice! Thanks guys. :)
     
  19. foxforcefive
    Joined: Apr 26, 2016
    Posts: 24

    foxforcefive

    Should just get a ford! I can't find parts for my 29 Chevy coupe but this was all great info and I'll make the parts I can't find


    Sent from my iPhone using The H.A.M.B. mobile app
     

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