"The Next One" - Handcrafted Mid-Engine Sports Car

[jlrussell4]

Nice Nick. It's good to see more process pictures - thanks.

[MAStuart]

Nick Thanks for posting. Last year at metal meet I tryed to make a roof panel for my coupe in one piece . My son and I also tryed at home without much success. At last years meet there was a shortage of experienced metal shapers . Most that were there had never made a panel that large. I was discouraged and started making the panel in a method that I thought would work for me. The roof panel is 3 foot long and 52 inches wide and has a similar shape to yours. The edge by the windshield does not need a edge tipped. The rear edge and sides need to be tipped. Anyhow I made in 4 panels welded acrossed the middle. 7 foot of weld. When i started to make progress it made me think I would like to try to do it again in 1 piece. Your post makes me want to try even more .

Nick, Is there any chance you could go into more detail on making this roof panel? I saw your picture with the lines drawn on it and I don't really know what they represent. I assume you did some shrinking on it? A more detailed process on how you made this panel would be of great interest to others in this group. Thanks again for posting! Mark

[iNVision]

Originally Posted by MAStuart

... Is there any chance you could go into more detail on making this roof panel? I saw your picture with the lines drawn on it and I don't really know what they represent. I assume you did some shrinking on it? A more detailed process on how you made this panel would be of great interest to others in this group. Thanks again for posting! Mark

Hi Mark,

Great question b/c rather than babble on and on...I can focus on answering you directly. I've been following your thread. You're doing excellent work and making great progress! Don't let the roof get you down. It looks similar(ish) to the one for R2.

I found this roof panel for R2 a bit tricky to get right. To start off with I used a sheet of plastic... since I didn't have paper large enough to represent the actual size of the roof. The plastic was laid over the wire frame buck and trimmed to an approximate size. While fitting it I was looking to see where it was tight(had to be stretched) and where it started to bunch(needed shrinking). Since I don't have the equipment to do some deep shrinking...the only option I had was to stretch the center of the sheet in a controlled manner and leave the perimeter alone.

Looking at the photo below...

The blue lines are more or less a guide to represent the wheeling boundaries and the red diagonals are the wheeling direction needed to get the panel 'up'. Wheeling a panel diagonally rather than front to back...and side to side increases the contact area of the anvils - thereby producing faster and cleaner results. This statement will probably start a rock throwing contest...but I use what works for me. Not to say that I don't use the perpendicular manner (for final washing I went front to back...following the curvature of the panel).

After about 30 minutes the crown was coming up nicely. This brings us to the green lines representing a stretch gradient on the corners.


From this initial fit on the buck I saw that the edges over the doors needed to come down some more. By focusing to stretch the area within the green with a sharper anvil the areas over the doors came down to the required curvature. This however created another issue with the centre...there still wasn't enough material creating an oil can. So in went the flat anvil and some more wheeling took care of this.

I don't normally use the Lancaster shrinking machine on low crown panels since it has the potential of creating unwanted stresses within the panel. But this roof has enough shape to it that a little shrinking wouldn't hurt to tighten up the perimeter. When the panel is cut to the final size these shrink marks were cut away.

Longitudinal features over the doors had yet to be put in...but I'm gonna leave that madness for another day.

Hope this provided a little more insight and didn't create anymore confusion.

Plan out what areas need to be stretched, take your time with the panel, watch what's happening to it as your rolling and trust your buck(reference it as many times as you need to...with the panel). Also, the person on the other side of the wheel needs to be totally in tune with you while you're rolling.

[jlrussell4]

Hi Nick,

'

. Wheeling a panel diagonally rather than front to back...and side to side increases the contact area of the anvils - thereby producing faster and cleaner results. This statement will probably start a rock throwing contest...

No rocks here as I wheel like that all the time.

[rokcrln]

I agree I do the same on door and roof skins as I find my results are faster and smoother before washing over the piece. Great progress!

Kevin
LFD Inc.

[anders nørgaard]

No rocks here eeither, but can anyone explain WHY it works like that? Usually we're told that the only thing metal understands is psi

Which anvil radius?
How much/little pressure?
Tanks!

[iNVision]

Originally Posted by jlrussell4

Hi Nick,

'

No rocks here as I wheel like that all the time.

Hah! That's awesome Mr J.!! And here I thought the diagonal wheeling pattern was something I conjured up.

Shortly after building my wheel I was messing around with a door skin wheeling it front to back...side to side. The crown was coming along nicely but I had little dips throughout the panel and you could see where it was wheeled. I got thinking about what was causing these dips and what could be done to eliminate them before they happened. After some thought and studying the anvil contact area I discovered that if the panel was rolled diagonally I could spread out and increase the anvil contact area. To verify this I took two straight edges held them perpendicular to each other...then started turning them so that they were at an angle to each other. So, I set the door skin aside and started again with a fresh sheet. Marking out the wheeling boundaries as well as a diagonal wheeling pattern - about 30* to the horizontal I started rolling again. To my amazement the crown came up much quicker and the resulting finish was very smooth with no dips and tracking marks.

[iNVision]

Originally Posted by rokcrln

I agree I do the same on door and roof skins as I find my results are faster and smoother before washing over the piece. Great progress!

Kevin
LFD Inc.

Originally Posted by anders nørgaard

No rocks here eeither, but can anyone explain WHY it works like that? Usually we're told that the only thing metal understands is psi

Which anvil radius?
How much/little pressure?
Tanks!

As I was typing my response to Mr. Russell I guess your two replies came in. I tried to explain why I think you can attain better results.

Thanks Kevin!

Anders - as for the anvil radius I've used the 12.0 and sometimes the 8.5...Pressure is hard to describe in terms of a quantitative value. I'd say just under medium pressure.

[anders nørgaard]

Thanks Kevin I'll give it a try.

[iNVision]

Originally Posted by anders nørgaard

Thanks Kevin I'll give it a try.

Kevin??