Heat one hour per millimeter of thickness for thin sheet at least two hours total.
Annealing acrylic sheet.
When to anneal acrylic sheet annealing minimizes the effects of stress on items fabricated from acrylite sheet.
Annealing the strengthening of acrylic sheet through controlled heating and then cooling minimizes the effects of fabrication stress.
Cooling times are generally shorter than heating times see the chart below.
Tips for annealing acrylic sheet.
Annealing the acrylic allows fabricators to strengthen the acrylic sheet and reduce or eliminate the fabrication stress through a process of controlled heating and then cooling.
To anneal acrylic sheet heat it to 180 f 80 c just below the deflection temperature and cool slowly.
It alleviates most of the stress induced by line bending thermoforming screen printing cementing machining buffing flame polishing and other fabrication operations.
Annealing consists of prolonged heating of the acrylic part at temperatures lower than those used for forming followed by slow cooling.
Sometimes formed parts are placed in jigs to prevent distortion as internal stresses are relieved during annealing.
Internal stresses in the sheet can cause crazing the appearance of numerous tiny cracks in the material when acrylic comes in contact with solvents such as glass cleaners or paints.