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Old 12-15-2005, 07:59 AM
Shabby chic sheet metalshaper
 
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Making a reverse shape in sheet metal

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
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Old 12-16-2005, 09:26 AM
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Brian Martin,Freelance adviser
 
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Good stuff John, thanks.

Brian
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Old 12-16-2005, 11:28 AM
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Good ideas John,, be sure to let us know when you plan on the meet, I'm looking forward to it,,, Bill
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Old 12-16-2005, 04:49 PM
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Thanks Brian and Bill. Bill I will do that.

Here is a little more progress. This is the most intuitive metalshaping I've ever done. If you feel a high spot, simply shrink it. The easist possible way to get fantastic results in my opinion. All other methods of shaping come with their own difficulties in getting a panel to behave the way you expect. Other methods make it difficult to get a near perfect panel.... for instance using an english wheel, or planishing hammer. These tools require more skill to operate.

It would be silly to try shrinking only on everything you wanted to shape, but for some projects, this is the cat's meow.

John
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Old 12-16-2005, 09:24 PM
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That's cool, there's definately a lot of power pulling going on with that shrink area.
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