I Don't Know Why....
.... but I've always shied away from annealing. I know how to do it but I suppose I've never had a good enough source of heat. A year or so ago, to solder up the fuel tank, I bought a roofer's torch and yesterday I was faced with a compound curve job on a relatively small piece of aluminium.
I had in the cupboard a bar of French soap without all the anti-aging, moisturising and slippery stuff in it and rubbed it on the panels. I don't know why I haven't done it before; it worked like a charm. It was still a bit of a fight and getting the metal to go round all the corners took time and the result is no great shakes but, I couldn't have done it without annealing the sheets first. I only wish I'd annealed the top bonnet panels instead of struggling all day to get them right.
And, talking of bonnets; I drew out the positions for the louvres and did a test piece to see if my old beech tooling still performed. It did but cutting through the aluminium with a Dremel cutting disc was a slow and tedious business. The discs shatter fairly easily and to prevent that, each slot takes about 10-15 passes. Each louvre was going to take me about 20 minutes to form and then they'd look a bit too hand-made.
I rang some relatively local chaps that I'd learnt were set up for just such an operation and bunged the two side panels in the back of the car. They could do the various sizes but one of their press tools was almost exactly the same length as the longest louvre on the left of the picture so they're going to do that size all across the panel (and for a lot less cost than all the different sizes).
On The Great Collector's 1914 Darracq, there's a very nice detail that keeps the bonnet taut to the radiator and scuttle wall. It's a simple dog-leg strip mounted on the wooden base plate that runs along the chassis rail and into which the return on the bottom of the bonnet panel is introduced when closed. There aren't any bonnet catches on the Darracq, just a couple of cups rather like drawer pulls. I'll put catches on mine as well because the panels are bound to fly about if I don't.
I next set about the windscreen. You can fiddle on and be anxious about getting the holes in the right place all day if you're not careful so I slapped the offside pillar on about where I wanted it and aligned the nearside pillar to it. That was the easy bit.
The channel support is a shaped piece of ash (miraculously, I got both sides right first time) and the aluminium channel is stuff I bought from the local DIY store. I would have liked to have used brass channel (easy to TIG braze) but it's so ridiculously expensive.
Why? I don't know.