 Making a tricky bit of metalshaping simple, Making a reverse curve |
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| John Kelly |
 Dec 16 2005, 07:13 AM
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#1
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Senior Member  Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640  |
I've been working on a method for making mild reverse shapes that is a little easier than stretching the edge of a panel. A reverse is where instead of a crown or bulge in the body, you have a concave area. An example of this would be the cowl area on some early cars....or where a fender flare blends in with the body on a later car. In this case, you would have a normal outward curve up and down and a reverse curve front to back. Usually you stretch the edge of the panel that you want the reverse shape in to make it grow and create a valley just inboard of the edge. You stretch a lot on the edge and less as you blend the reverse into the panel. This can be very tricky, and your panel can get away from you.
Using a crowned shrinking disc, I made about 12 passes in a sample piece. The sample was rolled over my leg first to make a curve similar to what I would do for a fender flare where it meets the door gap. Instead of stretching the edge, I shrunk the valley. The panel is a little easier to control this way. I've attached three pictures. The first one is an example of a typical reverse. The reverse is where my hand is pressing on the flow strip. The fender flare was stretched making a valley (reverse) in the transition area between the flare and body. The second and third pictures are of the test panel I shrunk a reverse in. I will be playing with this method some more to see how far I can take it. I think a combination of shrinking the valley and a mild stretching of the edge will come in handy at some point. John www.ghiaspecialties.com Attached image(s) 
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Replies(1 - 7)
| John Kelly |
Dec 16 2005, 07:16 AM
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#2
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Senior Member Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640 |
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| John Kelly |
Dec 16 2005, 07:17 AM
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#3
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Senior Member Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640 |
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| rick 918-S |
Dec 16 2005, 07:54 AM
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#4
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Hey nice rack! -Celette Group: Members Posts: 20,492 Joined: 30-December 02 From: Now in Superior WI Member No.: 43 Region Association: Northstar Region 
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Nice work John. Your a talented guy. Have you heard of Casimir Nawrocki? He's a friend of mine. Every time I visit him he's working some magic with metal.
Did you anneal that sheet first? Looks like it's slightly blued. |
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| John Kelly |
Dec 16 2005, 09:10 AM
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#5
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Senior Member Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640 |
Hi Rick,
Cass Nawrocki! Yes I've heard of him. A very innovative metalshaper from what I understand. Steel does not require annealing to shape it, but some folks think the shrinking disc does anneal. I don't know if this is true or not. I do know that you can work the metal for a long time without failure. Thanks for the kind words, John www.ghiaspecialties.com |
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| John Kelly |
Dec 16 2005, 04:35 PM
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#6
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Senior Member Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640 |
A little more progress...this is the most intuitive metalshaping concept I have ever come up with. Dead simple. Feel a high spot, shrink it down. It does not get any easier.
John www.ghiaspecialties.com Attached image(s) 
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| McMark |
Dec 16 2005, 06:09 PM
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#7
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Doesn't the shrinking disk get harder and harder to use as you get more reverse? Or I guess you're probably shrinking on the "back" side.
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| John Kelly |
Dec 17 2005, 07:58 AM
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#8
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Senior Member Group: Members Posts: 692 Joined: 1-May 03 From: Moclips WA. Member No.: 640 |
Hi Mark,
I'm not using one of my flat shrinking discs. This is a crowned disc that I just started making which easliy reaches into a valley. If you were making a super reverse (think potato chip), shrinking from the other side would be a consideration at some point. I wish I had tried this when doing the reverses on Felix's flares... John www.ghiaspecialties.com |
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