Bending plexiglass?

[2rods]

Need to make a replacement sunroof glass as I can't seem to find a replacement. Was thinking of making it from plexiglass but will need a slight curve the whole width of it. Would a heat gun applied very carefully achieve this? Any help or suggestions appreciated. Thanks guys.

[Dave]

Need to make a replacement sunroof glass as I can't seem to find a replacement. Was thinking of making it from plexiglass but will need a slight curve the whole width of it. Would a heat gun applied very carefully achieve this? Any help or suggestions appreciated. Thanks guys.

Be very carefull as if you get it too hot your all done. Also id use lexan not plexiglass.
Dave

[1FATGMC]

I'm going to have to make a canopy for my lakester and have been trying to look into this a little.  Below are a couple posts I've copied along with a couple links that might be of help.

For what you are doing I would build an open topped box that you could put the lexan over the hole and clamp it to seal it.  Then either pull a vacuum on the box as you heat it or pressurize the box as you heat it.

Good luck and let me know if you had any luck,

Sum

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Date: Mon, 22 Aug 2005 13:08:28 -0500
From: Sparky <wmtsmith@landracing.com>
Subject: Canopy ---Lexan XL 10 .093

Called their help line:

Cold forming:  you can cold form XL 10 --a curve that has a radius that is 100 times the
Thickness---i.e.  9.3 inches in this case without stress marks or cracks.

Hot Forming:  in a convection oven at 320 deg. F with a top and bottom forming mold or
frame.  This will make it take a set---as this stuff has a memory.  

32"x44"  .093 at Home Depot  $30.00


 "Sparky"
Lakester 2211

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Making the windshield is a story in itself. Buying Plexiglas was easy but how did you form
it? Turns out that I found a WW 2 military tech book called "Field Repairs for the P-40".
It told me to heat motor oil "to smoking temp" and put the Plex in it. It further said to put
the hot Plex between two molds which were lined with "Bunting cloth" and stand on them
to press the Plex into shape. The hardest part was figuring out what Bunting cloth was.
Getting my buddies to stand on it with me was easy.

The first Phantom fairings all used 1/8" thick windshields. And they were all compound
curves (meaning bowed in both directions). They looked best but the compound curve
was hard to form and was prone to bending backwards under speed. Some early Phantoms
used struts to hold the windshield up. The AMA Phantom has struts.

Very soon we changed over to simple curved windshields 3/16" thick which solved all
problems.

I learned a lot about windshields with the Series 1500.

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http://www.wisil.recumbents.com/wisil/bubbles/hpvbubbles.htm


http://www.sportaviation.org/magazine/2004_summer/canopy.pdf

http://www.craigvetter.com/pages/470MPG/high%20mileage%20fairing.html

[2rods]

Used a heat gun on one side and ended up with perfect fit. Having trouble with other side. Maybe gunshy as the first side started going on me. Have to give'er and hope  Thanks guys.

[unklian]

The HPV (human powered vehicles)guys are big on
blowing plastic shapes for bodies.

[MrMopar64]

Need to make a replacement sunroof glass as I can't seem to find a replacement. Was thinking of making it from plexiglass but will need a slight curve the whole width of it. Would a heat gun applied very carefully achieve this? Any help or suggestions appreciated. Thanks guys.

Be very carefull as if you get it too hot your all done. Also id use lexan not plexiglass.
Dave

I was told years ago when I made the rear window for my chopped 64 that if I was going to heat it to shape it not to use Lexan as it would tend to bubble when heated
I never tried it so I don't know first hand  :?

MM64  

[2rods]

Got her perfect. Don't know what type of plastic it is. Got it from a friend and it really doesn't matter as long as it covers the hole. For a race car so will never see any rain we hope.