Acrylic Vs Polycarbonate

There's a few different ways to heat it. The cheapest way it to make your own heater. You can use old toaster oven heating elements and attach them to a variable switch ( dimmer switch ) to adjust the temp. The elements must be above the poly, below will result in bubbles. Please dont try this if you are not comfortable with electricity!!! It is easier to use a mold to get the exact form. Yes, I get my lexan from a reel.

Here is some methods of poly bending:
Cold Bending:

Polycarbonate sheet may be cold bent with the minimum radius based upon the sheet thickness. As a guideline, the material can be radiused to 100 times the thickness: (R=T x100)

Cold Bend Radii

Sheet thickness (T) Minimum Radius (R)
1/8" 12.5"
3/16" 18.7"
1/4" 25.0"

Note: polycarbonate abrasion resistant sheet is recommended for flat glazing only


Thermoforming:

Polycarbonate sheet can be thermoformed on standard equipment. Vacuum forming, free blown forming and line bending are most extensively used processes. While most standard forming techniques can be used, critical process modifications specific to polycarbonate are necessary to ensure uniform and repeatable formed parts.

Predrying polycarbonate sheet:

Polycarbonate sheet must be dried before thermoforming because polycarbonate absorbs moisture at a high rate. Trapped moisture forms vapor above 250°F, and the vapor expansion creates bubbles in the sheet. Sheets of polycarbonate should be placed in a dehumidifying air circulating oven for predrying with approximately 1" separation between sheets. Oven temperature should be 250°F and monitored with controls. Recommended predrying time periods are shown below. A note of caution-polycarbonate sheet begins absorbing moisture immediately upon removal from the predrying oven. The rate of absorption is dependent upon the ambient dew point. For this reason, it is crucial to transfer the sheet directly to the forming machine as quickly as possible.



Gauge Drying Time (Hours)
.093" 4
.125" 6
.187" 14
.250" 24


Heating Cycle:

Heating polycarbonate sheet for vacuum forming requires heat penetration to achieve a 360°F to 375°F. When polycarbonate sheet reaches forming temperature, uniform "sag" occurs. The amount of sag depends on the size and thickness of the sheet. A 12" x 12" a .060" sheet will sag approximately 1". A 36" x 36" a .177" sheet may "sag" 4"-6" at the center. Once uniform temperature has been achieved, timers can accurately reproduce the condition, and part-to-part consistency can be maintained

Helpful Hint:

Polycarbonate sheet "sets up" very quickly compared to other thermoplastics and can be removed from the mold in a short period of time. Caution: polycarbonate sheet remains quite hot during this cycle and care must be observed when handling finished parts. Throughout the vacuum forming process, it is imperative that dust and dirt be controlled. Polycarbonate sheet has a static charge that attracts foreign particles which can create surface imperfections. Molds also attract dust particles and should be cleaned to avoid creating surface defects.