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Old 11-17-2018, 06:01 PM
RB86 RB86 is offline
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Join Date: Nov 2018
Location: Charlotte NC
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Quote:
Originally Posted by Rick Mullin View Post
You are correct John. Sorry for making the assumption.

Shape is the stretching (thinning) or shrinking (thickening) of the sheet metal. By stretching, you are increasing the surface area and by shrinking, you are decreasing the surface area. Most panels have both types of shape put into them. Form is the bending of the panel without changing the surface area.

When making a panel, concern yourself with the shape not the form. Make a paper pattern or flexible shape pattern and use that as your guide for how much shape and where. The pattern has no regard for form. If you match the shape in the pattern, bending the panel (forming) will yield the desired result of a finished panel. A common problem for many people when making a panel is that they think that the panel should progressively look like the finished product as they are wheeling or hammering. Not so. As long as the shape is correct, the panel's form can be manipulated at the end. The only exception is in making a reverse curve where the shape is generally creating the bulk of the form at the same time.

By manipulating the form, you can use lower crown anvils or planishing dies to transition and smooth the panel. Adding form is also important in shrinking. By arching a panel, it removes the load on the shrink allowing more material to be gathered.

I hope that was a helpful explanation.
That is good food for thought, thank you.

I've noticed that basically everytime I finish hammering out the middle for stretch, the overall form has folded closer, so I lay it on the ground and push the edges outward.

Easily the biggest challenge of this piece for me is the left and right side (when looking straight at the panel) not wanting to curve downward onto the buck. I have continued to hammer and stretch the center upward so these sides have clearance and can come downward when resting on the buck. Still a challenge though. I've stretched the middle so much that when looking inside it's barely touching the stations, and it's mainly the backbone causing that teeter left and right. I've hammered out the middle to get out of the way but it's hard to achieve the stretch I need along that edge. Getting there little by little.
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1950 Cadillac
1956 Cadillac
Looking to build my own car from scratch
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