There's a bit of a rust issue with the tailgate on the lowlight which is also causing a bit of a leak and water to get into the bus. The rust is on the bottom of the window under the window rubber so to repair it the rear glass will need to come out. Whilst pondering the best way to fix it I had a great idea - why not replace the rear window with an opening 'safari' window. This way I could make the repair to the rust at my leisure rather than having to get it done in a hurry.
However, having taken a look at rear safaris I decided that they were probably an expense I didn't need right now, especially as the lowlight was a project that I did not plan to work on at the moment. Not put off, I decided that I would have a go at making one myself.
Looking around on the web there are a few companies making safaris, there are of course the usual suspects such as Creative Engineering but then there are a few new outfits having a go too. Some of these smaller companies are using some very interesting methods to make the curved sections including pie-cutting and welding the frames to form the curves, a very labour intensive exercise. I decided that even if I only made one window that was not the way I wanted to do it.
Drawing on my experience with metal forming I decided that I would have a go at trying to form the bend, either by pressing it, or bending / rolling it using a mandrel. Ideally I would liked to have pressed the corners but as I do not currently have a suitable press I decided that the best way to go about this was to try and adapt a ring rolling machine. These machines are generally used for rolling flat bar and round bar into curves. I figured that if I made some suitable dies I could roll the curve instead.
First off I needed to find a suitable material to use. I figured that aluminium would be soft and easy to bend and managed to find some with a suitable profile at the local DIY store. I also picked up some rubber to hold the glass in the aluminium channel, some weather seal strip to put around the window aperture and a piano hinge to hold the window in with. With the material selected I went and purchased a ring rolling machine and set about making a new set of dies for it.
Making up the new dies was relatively straight forwards, I turned them down on the lathe and then filed keyways into them so that they would fit onto the die roller. With the new dies fitted I did a test run. The results were mixed: The channel did bend and the side wall of the 'U' section did not wrinkle up or split, the dies kept the side wall perfectly straight - so a bit of a win there. However, an unwanted side effect was that the bottom of the 'U' split along the corners. I've figured out that this is most likely due to a lack of support of the sidewall in the mandrel as the 'U' section is being rolled and the only real way to fix it is to make a new die up so that the sides are supported correctly. However, this is job that can wait until next weekend.
Overall I'm very pleased with the results, it works very well but until I fix the issue with the dies I cannot roll a radius tight enough to be able to make the rear safari for the bus. I believe that it would be a tight enough radius to make the windscreen surround for the speedster but as the speedster uses a round profile I need to make a different set of dies for that anyhows.