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  #1  
Old 04-03-2019, 04:47 PM
metalmarks metalmarks is offline
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Default Sprite bonnet reverse curve help please.

Hello everyone!
I attempted this in steel with terrible results, so I switched to some soft, thick aluminum, so at least it would take less effort to get another terrible result.

IMG_3768.jpg
IMG_3769.jpg
IMG_3765.jpg
I made a flexible shape pattern from the bonnet, and I think I'm pretty close to matching it with the aluminum, but I can't see why it won't wrap downwards.
Please offer some advice!
Thanks very much, in advance!

IMG_3766.jpg
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  #2  
Old 04-03-2019, 06:56 PM
mark g mark g is offline
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Hi Chris,

I'm in Rockingham VT!

If the long edges are down and the short edge is lifted, the edges need more stretching. You have to look at the pattern very closely and take every slight deviation from perfect fit to mean something needs changing.
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  #3  
Old 04-04-2019, 12:43 AM
Peter Tommasini Peter Tommasini is offline
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Chris
In my opinion the first mistake you have made is to use and work off a flexible pattern,
(it shows the shape of the panel YES) !BUT it does not show where the stretching is ...or at least how far to stretch and where the bulbous shape begins .....and in any case why would you want to have the shape on the flexible pattern ....when you have the shape of the real panel in front of you?? The second problem that you have there, is that you cut the blank too small, there for to hard to work out what is what and no room for error or blending the two shapes together

Having said that.... you can please your self the way you would like to pattern things or approach that shape
but I would do that task this way.........................

N 1 use masking paper to make the pattern about 2/3 inches bigger all the way around
N 2 cut the paper pattern with a blade where the return is...(the paper will spread to a V and sit properly on the panel) that is where the stretching begins and finishes, you will note that the stretching is heavier at the beginning and less how you work in to the panel . The bulbous shape on pics N 4 (where your fingers are) will appear automatically when the stretching is completed at the end and the side of the panel. All you need to do then is to put some shape on to the bulbous shape and blend it all in. The most important thing is to have plenty of material to start with, and cut it down to size while working on it
to make things easier to understand what is going on, make the pattern as I suggested and do what the pattern tells you... cut.... (meaning stretching back and side ) Tuck it (meaning shrinking the very front)

PS [ your Quote]......................

I think I'm pretty close to matching it with the aluminum, but I can't see why it won't wrap downwards.

Answer...the top and the side are not long enough, stretch them more ......like the pattern will show you, then shrink the very front (where the middle of the radius for the front grille opening is do that by 1 tuck going all the way about the length where the black line is on your first pic ..... to the end of the bulbous shape
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Last edited by Peter Tommasini; 04-04-2019 at 07:16 AM.
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  #4  
Old 04-04-2019, 01:32 AM
Jaroslav Jaroslav is offline
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Peter. Would you make it in one piece?

I have a similar task, but so far we have not succes. I started from the other side. I found that a sharp bend keeps the shape better. I want to do it in one piece.
But radiuses go to all sides ....... It is very difficult part.
This part determines the shape of the car. From the top of the hood, from the bottom front mask.

I will try to bend the sharp bend first in both directions and the larger radius can be moved in the surface by use my EW.

DSC00126.jpg

DSC002191.jpg

First try.
DSC00124.jpg

Second try.
DSC00222.jpg
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  #5  
Old 04-04-2019, 06:35 AM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by Jaroslav View Post
Peter. Would you make it in one piece?

I have a similar task, but so far we have not succes. I started from the other side. I found that a sharp bend keeps the shape better. I want to do it in one piece.
But radiuses go to all sides ....... It is very difficult part.
This part determines the shape of the car. From the top of the hood, from the bottom front mask.

I will try to bend the sharp bend first in both directions and the larger radius can be moved in the surface by use my EW.

Attachment 52171

Attachment 52172



First try.
Attachment 52173

Second try.
Attachment 52174

Jaroslaw.... the two panels (yours and the one above) are a complete different task to form them, there is a different way to approach the two.......

With your panel in question....you are on the right track but you need to turn each side one at the time NOT AT THE SAME TIME like you have done on your pic
meaning......Do your wheeling on the top of the blank (lot's of it!) then turn the first flange downwards, shrink it to suit, once that is done brake the second flange back to the same plane of the top surface, but be careful this exercise WILL SHRINK THE PANEL AROUND FURTHER so stretch it as you turn it till it's at the same plane of the top surface and the right shape. After that insert a piece of plate the same width of the Chanel, and turn the last SMALLER flange up. Once that side is right shape and all.... repeat the same exercise on the other side
Peter
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Metalshaping tools and dvds
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Metalshaping clip on youtube
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Making Monaro Quarter panel:
http://www.youtube.com/watch?v=KIpOhz0uGRM

Last edited by Peter Tommasini; 04-04-2019 at 07:03 AM.
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  #6  
Old 04-04-2019, 10:37 AM
metalmarks metalmarks is offline
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Default Another attempt.

Hello, and thanks for the advice!
I tried another test piece this morning, with slightly better results. Peter, I'm not sure where it was that you suggested a tuck shrink. Is it at #1, 2, or 3?
I wound up stretching at all 3 spots.
IMG_3771.jpg

IMG_3772.jpg
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  #7  
Old 04-04-2019, 04:17 PM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by metalmarks View Post
Hello, and thanks for the advice!
I tried another test piece this morning, with slightly better results. Peter, I'm not sure where it was that you suggested a tuck shrink. Is it at #1, 2, or 3?
I wound up stretching at all 3 spots.
Attachment 52175

Attachment 52176

Chris
looking at your last test piece you might need a shrink where the black line is in your first posted pic ,but keep in mind that when you turn the nose panel under (the grille opening ) all of that stretch metal will be needed, but at this point I would only stretch N 2 a bit more on the edge.
Peter
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Metalshaping tools and dvds
www.handbuilt.net.au

Metalshaping clip on youtube
http://www.youtube.com/watch?v=WEAh91hodPg

Making Monaro Quarter panel:
http://www.youtube.com/watch?v=KIpOhz0uGRM
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  #8  
Old 04-04-2019, 07:03 PM
Jaroslav Jaroslav is offline
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Quote:
Originally Posted by Peter Tommasini View Post
Jaroslaw.... the two panels (yours and the one above) are a complete different task to form them, there is a different way to approach the two.......

With your panel in question....you are on the right track but you need to turn each side one at the time NOT AT THE SAME TIME like you have done on your pic
meaning......Do your wheeling on the top of the blank (lot's of it!) then turn the first flange downwards, shrink it to suit, once that is done brake the second flange back to the same plane of the top surface, but be careful this exercise WILL SHRINK THE PANEL AROUND FURTHER so stretch it as you turn it till it's at the same plane of the top surface and the right shape. After that insert a piece of plate the same width of the Chanel, and turn the last SMALLER flange up. Once that side is right shape and all.... repeat the same exercise on the other side
Peter
Thank you Peter. I'll try it. I started from the wrong side. I can move the radius with a larger radius in the desktop without much trouble. The limiting dimension is the sharp edge. I have to start there. I started upside down. I don't know if I will be can, but I'll try.
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  #9  
Old 04-04-2019, 07:07 PM
Jaroslav Jaroslav is offline
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Quote:
Originally Posted by metalmarks View Post
Hello, and thanks for the advice!
I tried another test piece this morning, with slightly better results. Peter, I'm not sure where it was that you suggested a tuck shrink. Is it at #1, 2, or 3?
I wound up stretching at all 3 spots.
Attachment 52175

Attachment 52176
Chris, it looks good. Sometimes a simple thing know do can gets complicated. Good luck.
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  #10  
Old 04-05-2019, 05:49 AM
metalmarks metalmarks is offline
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Thanks everyone, for the advice and encouragement! I’ll do some more work on it, then attempt the flanges.
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