I made the front section by first making a pattern out of an old lump of hardwood. Well, to be honest, I got my father to do it
, as he was a shipwright (ship's carpenter) and was used to making patterns.
This was sized to fit inside the front end of the sill. Next, I got some thin cardboard (ie poster stuff from a newsagent) and carefully "wrapped" it around the hardwood pattern, using scissors to trim excess from where it folded over on itself as the sill got smaller at the end.
Finally, I traced the cardboard template onto a section of my newly folded sills, cut the excess bits out with tinsnips, firmly clamped it all down and then shaped it around the hardwood pattern using a hammer and sometimes a small cold chisel to punch it down into concave areas. I also tried using heat from the oxy to help shaping the metal, but this tended to burn the hardwood pattern so I gave up on it. Fianlly, welded up the cut areas, reshaped a bit with hammer and dolly, took to it with an angle grinder and it looked pretty much like it should have. A bit rough in spots, but better than a rusty mess. I reckon I could get quite a professional looking job after a few more attempts, but I have no desire to do it any more times than I have too
I didn't attempt to form this on the end of a complete sill, but rather onto a section about 300mm long, then welded this back onto the correct length of sill before fitting to the car. Only because I lacked the confidence to manage larger lengths.
First side took ages, but once I was happy the second side went quicker. You still need two mirror image hardwood blocks though.
Only cost something like $30 for the sills from the sheetmetal place, and a few weekends of my time.
And fr3ak, I will soon be attempting to make 180B SSS sills plus the section of the rear quarter in front of the rear wheel, this time using a template made more like an model aeroplane wing (ribs and stuff) to try to get the corect rounded shape. I use oxy cause thats all I have, but I reckon pop rivets are getting a bit on the weak side for the sills, which add a fair bit to the structural strength of the shell.