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Old 05-27-2020, 01:45 AM
Bandit12352 Bandit12352 is offline
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Question How to make a lower crown panel?

I'm making a roof for a 280zx, and I made patterns and gauges (like Wray Schelin ) and when I get the gauges to fit going say left to right, then front to back becomes out of wack and then I'll fix it and the left to right gets messed up, This may be hard to answer but how do I get the panel to go the way I want it to go in both directions without it fighting me.

I understand that you need "area" for the "arrangement" to fit but I just can't seem to get it.

Any feedback is welcomed.
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Old 05-27-2020, 07:51 AM
Jaroslav Jaroslav is online now
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Give me a photo. If you are making a large panel I have solved a similar problem. I lift the edge of the panel upside down. Approx. 40mm. The panel does not twist and holds its shape. After shaping, cut or bend as needed. But the shape already holds the dimension as you need.
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Old 05-27-2020, 10:47 AM
Chris_Hamilton Chris_Hamilton is offline
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Sent you a PM Bandit.
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Old 05-27-2020, 03:43 PM
Ken Hosford Ken Hosford is offline
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your challenge is to put the right shape into the roof section l The presentation of the shape can be flip flopped from to much in one direction not enough in other to visa versa . With that said you might try FSP [flexible shape pattern ] that will show you when you enough or to much shape
center loose not enough shape edges loose to much shape
If you are not familiar with FSP search it on this site
It will help if the section is symmetrical when you check you shape with your gauges lay it on floor with 4 corners down that should help understanding how much shape or how little you have Good luck some times sleeping on really helps walk away for a day or two
The pain you are feeling is all part of the building blocks of knowledge ,when you have gotten on the other side of it the frustration gone you are left with learned lessons and knowledge to be applied in the future
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Old 05-27-2020, 04:31 PM
Bandit12352 Bandit12352 is offline
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Default Ken Hosford: reply

one of the patterns I am using is a FSP and the panel doesn't really have enough shape for it to be of any good I will post a picture of the area I'm trying to recreate (some will probably laugh at how simple it looks) The FSP helps but its not like a E type pattern where its supper obvious where it wants wheeling or arrangement or etc.

car roof1.jpg

car roof2.jpg

car roof3.jpg
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Last edited by Steve Hamilton; 05-27-2020 at 09:49 PM.
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Old 05-27-2020, 05:02 PM
Bandit12352 Bandit12352 is offline
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Default pics

I have posted pics just now

Quote:
Originally Posted by Jaroslav View Post
Give me a photo. If you are making a large panel I have solved a similar problem. I lift the edge of the panel upside down. Approx. 40mm. The panel does not twist and holds its shape. After shaping, cut or bend as needed. But the shape already holds the dimension as you need.
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Old 05-27-2020, 05:04 PM
Bandit12352 Bandit12352 is offline
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Default One more thing

I have already tried the FSP but my panel is just not crowned enough for me to be able to tell what it wants.
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Old 05-27-2020, 05:23 PM
Jaroslav Jaroslav is online now
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I think that's the case I was dealing with. Small depression and no edge to hold the shape.
Use a larger plate, fire the edge up approx. 40mm and doing shape what you need. Then cut or use the edge. The shape you wanted to create is done. Everything else is extra material.
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Old 05-27-2020, 05:31 PM
Bandit12352 Bandit12352 is offline
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but when you cut the extra off won't it bounce back to being messed???

Quote:
Originally Posted by Jaroslav View Post
I think that's the case I was dealing with. Small depression and no edge to hold the shape.
Use a larger plate, fire the edge up approx. 40mm and doing shape what you need. Then cut or use the edge. The shape you wanted to create is done. Everything else is extra material.
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Old 05-27-2020, 08:21 PM
BTromblay BTromblay is offline
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Hi,

Several things to consider.

Form (arrangement) is altering a panel in 2 dimensions. (To bend the panel. To bend open, to bend closed, to bend over your knee, to put in a sheet metal brake and bend it)

Shape (area) is to alter a panel in 3 dimensions. (To put shape in a panel the material thickness must become altered. To stretch is to make it thinner, to shrink is to make it thicker). You may know this already, just to clarify so we all understand the same terminology on proceeding.

Your description seems to describes one or more issues with your panel.

If it snaps back and forth as if it has a lot of stress, this would be caused by several reasons and can be solved by low pressure wash passes with planish hammer or E wheel. Low pressure passes will cause the panel to relax.

If it does not snap back and forth, but you adjust the panel with bending (form/arrangement) and it fits in one direction, but not the other, it seems to me, it needs more (shape/area) to get it to fit.

Use one clamp and clamp it in the same spot every single time. Mark the panel with reference Mark's and go to the same spot every time. Where the panel touches your buck or structure is where you need to continue to stretch. Continue to use your gauges to confirm your progress. Your part looks close, but evaluating the last 5% between form and shape can be difficult at times.

Hope it makes sense.

Bill
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