It's been a while, but I haven't been idle, I started on fashioning a wooden former for the rear fender. It took three goes but I think the latest one is as near to the real thing as I'm going to get without having an actual fender to use as a pattern. I downloaded and printed about a dozen side-on pictures of CA77s and spent an inordinate amount of time taking measurements off of the pictures, then using reference points on my frame, was able to get a better idea of the shape and size of the flare at the bottom of the fender.
The wood was roughed out, then a skim of body filler was applied and sanded down ensure the fit was as close as I could get it:
P1036260 by
Happy Grandad2010, on Flickr
In order to follow the curves with a minimum of fuss, I cut mild steel sheet into strips, welded them into place until I got to here:
P1136261 by
Happy Grandad2010, on Flickr
P1136262 by
Happy Grandad2010, on Flickr
I know it looks a bit of a mess, but there's still plenty to do, I have some 3mm mild steel bar which I am going to use to wire the edges of the flare, then the outside edge will be trimmed to size and curled round the bar. I will then proceed to beat the crap out of it with a hammer and dolly to get in shape, clean up the outside welds, seam weld the insides and finally fill the outside joints with solder.
When the time comes for paint to be applied, a thin skim of filler should finish it off nicely.