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Old 03-13-2009, 12:48 AM   #15 (permalink)
cmittle
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Location: Sioux Falls, SD
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chevynova - '88 Chevy Nova
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Quote:
Originally Posted by Bicycle Bob View Post
Before vacuum-forming polycarbonate (Lex**) you should soak it at about 190 F for 8 hours to drive the moisture out, lest you get steam bubbles. Acrylic is still used on racing cars. It is on the brittle side, but is manageable. Uvex is probably the best for cheap and tough with easy formability.
For a simple shape like moon covers, you can use free-blowing or even sagging. You can also use a male mold, and drape the hot plastic over it, smoothing it with cotton gloves or rags.
Heat guns are good for controlled bulges; bad for even heating. Ovens can be uneven too - you might want to use some tricks to minimize radiant variations and circulate the air.
Unless you see smoke, the fumes are negligible - anyone worried about their kitchen oven could run it to a higher temperature, empty, to volatize any residuals.

I was under the impression that it needed to be placed with a dessicant to remove moisture from the material. I did a little bit of research that indicated this about a year and a half ago when I was drape forming a couple of things. Also I've toured an injection molding facility near my home town a couple of times and I remember they said they have to run the polycarbonate through a dehydrator system for a long time before they use it as well.

It sounds to me like you've done this before so maybe your trick works I'm just not sure that I follow. Could you elaborate?

thanks,
Cory
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