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GordMay · 07-02-2007, 06:12

Thermo-forming Lexan isn't easy.
To bend lexan (polycarbonate) and plexiglass (acrylic polyacrylate) your piece should be clamped firmly to a strong, stable surface, preferably indoors. Some recommend pre-heating in an oven, to reduce “torch time”.
Once you have clamped the piece begin to heat the panel, with a propane torch or high-capacity heat gun, along the line where you intend to have it bend. DON'T put the heater too close for too long, as this will cause the plastics to get cloudy, or even bubble up.
You'll know when the plastic is ready to bend, simply by applying pressure to the free end of your work piece.
Large pieces will require the help of a partner who can apply even pressure along the entire length of the bend, while you heat the plastic, keeping a uniform and consistent source of heat applied until you have achieved the desired bend. Thicker pieces require heating on both sides.
Lexan does not exhibit a sharp melting point, but softens gradually over a wide temperature range - beginning at about 300 degrees F (150 C), to melting at about 420 degrees F (215 C).

In addition to thermo-forming, most plastics can be cold bent (minimum bending radius must be 150 times the thickness of the sheet), without negatively affecting the integrity of the material. Materials 3/16” thick or less are typically easier to bend.

See also:

HOW TO HAVE SEXY WINDOWS!?

Techniques to rebed dead lights (windows)

07-02-2007, 06:12	#3
GordMay Registered User Join Date: Mar 2003 Location: Thunder Bay, Ontario - 48-29N x 89-20W Boat: C.L.O.D. (Cruiser Living On Dirt) Posts: 12,582	Thermo-forming Lexan isn't easy. To bend lexan (polycarbonate) and plexiglass (acrylic polyacrylate) your piece should be clamped firmly to a strong, stable surface, preferably indoors. Some recommend pre-heating in an oven, to reduce “torch time”. Once you have clamped the piece begin to heat the panel, with a propane torch or high-capacity heat gun, along the line where you intend to have it bend. DON'T put the heater too close for too long, as this will cause the plastics to get cloudy, or even bubble up. You'll know when the plastic is ready to bend, simply by applying pressure to the free end of your work piece. Large pieces will require the help of a partner who can apply even pressure along the entire length of the bend, while you heat the plastic, keeping a uniform and consistent source of heat applied until you have achieved the desired bend. Thicker pieces require heating on both sides. Lexan does not exhibit a sharp melting point, but softens gradually over a wide temperature range - beginning at about 300 degrees F (150 C), to melting at about 420 degrees F (215 C). In addition to thermo-forming, most plastics can be cold bent (minimum bending radius must be 150 times the thickness of the sheet), without negatively affecting the integrity of the material. Materials 3/16” thick or less are typically easier to bend. See also: HOW TO HAVE SEXY WINDOWS!? Techniques to rebed dead lights (windows) __________________ Gord May ~~_/)_~~ (Gord & Maggie - "Southbound") "If you didn't have time/$ to do it right in the first place, when will you get the time/$ to fix it?"