This probably isn't a lot of help, but I'll contribute what I can.
I started by putting a centerline on the scuttle and nose cone with painter's tape and a sharpie
Then parallel lines 6 inches either side of center. I wanted to be able to put the paper pattern on and off consistently.
I draped a triple thickness of heavy kraft paper over the car to start making my template. A bit of tape, some trimming, and eventually ended up with a good fitting paper pattern.
Attachment:
doll.jpg
I put it on and took it off about 5 times to be sure I was happy with the fit
Then laid it down on a sheet of 3003 aluminum .050 thickness. This wasn't marked with a temper, but I'd learned from experience it was 1/2 hard or better... too stiff to easily work. More on that later.
I'm not great at transferring lines from pattern to sheet, so I cheat. I lay the paper pattern on the aluminum and paint all around it. That's why you see the black paint on my paper template.
I rough cut the aluminum piece and put the center line and 6" offset lines on the aluminum. then put the paper pattern back on the car one more time to get the center of the bend radius marks like shown in the Chapman drawing. Transfer those to the aluminum sheet.
Now for the fun part. I mentioned 1/2 hard is too stiff to work. I drew a line 4 inches either side of the center line of the bend. Then, squiggly lines with sharpie in between to track the heat as I started annealing the sheet. Bust out the propane torch and start annealing. When the sharpie marks disappear, you're hot enough.
Once the sheet cooled, I brought it inside and got my son to help me bend it around a roll of vinyl I have. It's about 6" OD.
Attachment:
bonnet1.jpg
Attachment:
bonnet2.jpg
The rectangle is what I need to remove to clear the carb rack.
Attachment:
bonnet3.jpg
Last step is to get the edges prettied up. I used a [Fatherless Child] cut mill file and draw file the edge to get smooth and straight.
When I'm done with everything else, I'll most likely put on a rubber U strip to keep from screwing up my painted parts... (more)