A friend of mine has a turn signal housing from a 30's model truck, that has a plastic lens that is broken. The housing is about 4" round and 4" high. It's shaped like half a Mortons salt (round) container. On the front lid of the housing is slots for the center part of of the turn arrow and another two slots, at an angle, for the two legs of the turn arrow. Is there a plastic material, that when placed on the lid with the slots, (and heated) would sag just enough, to look like the original. Any sources for this plastic? Thanks, LC
In the late 50' & 60's a lot of lenses and dash knobs were being made by customizers. If I remember correctly, they were using Lucite sheets and blocks to form them. In the case of knobs, they would laminate sheets together, sometimes alternating colors. For lenses, a male mold or buck would be carved and the sheet Lucite (or Plexiglas) would be draped over the mold and put in a oven to soften and take the form of the mold. An oven works better than a heat gun brcause the heat is more uniform. Another possibility is to investigate the resins being used by model builders these days. Your may be able to 'pour' a lens. I think they can be opaque, clear or translucent, depending on the dyes used. I really don't know much about these processes, other than they are being done, but some research on model forums should yield a lot more useful info. Ray
If you have a little cash and time, go to Hobby Lobby and get an RTV mold making kit. There used to be a show called "Classic Car Restoration" on DIY Network and they did an episode on making new tail-lights using the cracked original to create the mold. Some follow-up info: The DIY link is no longer active but maybe it the episode could be found on youtube or google. This link has some helpful info. http://forums.sohc4.net/index.php?topic=16653.0;wap2
You could have a part vacuuformed by a small shop pretty cheaply, but it would involve your building a "tool". That is, you would have to make a pattern of the lens that could sit flat on a vacuum table- with a series of holes in it to allow the vacuum to suck the material down onto the tool. It doesn't have to be fancy- it could just be a slug of wood- chucked up in a lathe. But you have to make sure that the draw isn't too drastic or deep. I can't tell without seeing the part.
You could use the existing lens and make a duplicate with Alumilite. http://www.alumilite.com/HowTos.cfm
I think that's ^ the best option. But if you did want to try making it from heated plastic, you could try vacuum forming it. I've used small vacuum forming units to create dental appliances and it works great. You could take a plastic bucket with a lid on it (must be air tight), turn it upside down and drill a bunch of small holes in the bottom (now the top), and attach a vacuum cleaner hose to the side of the bucket. You would have to clamp the plastic into a frame, and heat the plastic in an oven. Then, with your model sitting on the bucket, lay the framed plastic over it, so the plastic touches the edge of the bucket all around (use a release agent like Vaseline on the bucket and model so the plastic doesn't stick), and turn on the vacuum, it will suck all the air out and pull the plastic tight around the model. After it cools you'll have to cut the piece out. I don't really think this is the best solution in your case, but this question has come up here quite a bit, and I never see anyone mention vacuum forming, so I thought I'd throw it out there.
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