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Old 10-25-2008, 02:02 PM
kari kari is offline
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Quote:
Originally Posted by mark View Post
not to go off topic but..

The link suggests annealing to prevent prevent crazing, how is that done with acrylic?
Easiest way to prevent crazing is to use cast material. Extruded is a crapshoot. Since the boss said no to anealing in the kitchen oven I used to warm up the extruded and bent parts beside my woodstove (not in the house) for a few hours. Here's a cut and paste explanation,

To anneal acrylic sheet, heat it to 180°F (80°C), just below the deflection temperature, and cool slowly. Heat one hour per millimeter of thickness – for thin sheet, at least two hours total.
Cooling times are generally shorter than heating times – see the chart below. For sheet thickness above 8mm, cooling time in hours should equal thickness in millimeters divided by four. Cool slowly to avoid thermal stresses – the thicker the part, the slower the cooling rate.
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