Forming polcarbonate

Discussion in 'Workshop Tips and Secrets / Tools' started by PTAirco, Feb 7, 2009.

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  1. Feb 7, 2009 #1

    PTAirco

    PTAirco

    PTAirco

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    Has anyone tried heat forming polycarbonate sheet, like Lexan as opposed to Plexiglass?

    I need to put some curve into a simple windshield, so it maintains a certain curve; more of an ellipse than an arc. I need it to maintain that curve by itself. Simply bending it will just result in an arc and won't do.

    Lexan seems to be very reluctant to bend from heat, I did some trials using a heat gun. Very unpredictable too. Does Plexiglass form fairly easy using simple methods? Has anyone tried it without resorting to ovens?

    I only need two simple bends really, no compound curves, but this stuff is not co-operating.
     
  2. Feb 8, 2009 #2

    Grimace

    Grimace

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    There was a great how-to in sport aviation maybe about 6-10 years ago on the subject. Perhaps search their archives?
     
  3. Feb 8, 2009 #3

    Dan Thomas

    Dan Thomas

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    Lexan can be bent like metal in a brake, but if you need gentler curves it needs the heat. Trouble is that it's rather unforgiving. It absorbs water and that alone can cause it to do stupid stuff when it's heated. It also gives off poisonous vapors if it's heated a little too much. Anytime I've tried to heat-form small pieces I get crazing.
    I'd Google "heat-forming polycarbonate" and see what comes up.

    Dan
     
  4. Feb 8, 2009 #4

    PTAirco

    PTAirco

    PTAirco

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    I'll try some Plexiglass on Monday and see how that goes. Lexan is great for flat panels, but this seems too much bother.
     
  5. May 26, 2009 #5

    lr27

    lr27

    lr27

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    I put a small piece of Lexan in an oven once and got a nice smooth, small radius bend. Took quite a bit more heat than plexi. Suggest going to a manufacturer's web site and getting specs. Once you have the bend, Lexan (or polycarbonate) will be much nicer to install because it doesn't split easily. Plexi splits so easily you can just score with a knife and break at the resulting line by bending over a straight support.
     
  6. May 26, 2009 #6

    flyranch

    flyranch

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    Lexan also shrinks when it is heated. Otherwise, it is almost indestructable whereas plexiglass breaks and crazes like mad. Unfortunately, lexan will also dissolve with gas. I have had fair results by using a heat lamp but I, too, prefer to use a brake for bending.

    I definately wouldn't use plexiglass. Way too brittle.
     
  7. May 27, 2009 #7

    Rom

    Rom

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    You have to look at all the angles when considering plexiglass vs polycarbonate. In a roll over landing (crash) with a bubble canopy you would be stuck if Lexan. A crash hammer would get you out of plexiglass.

    Mark
     
  8. May 27, 2009 #8

    BBerson

    BBerson

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    Lexan is soft and scratches cannot be polished out. So for long term use, most go with acrylic (plexiglass) even though it is brittle.
    BB
     

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