How to Mold Plexiglass

By Aaron Kopf
Plexiglass is used to replace broken windshields or windows.

The chemical name of plexiglass is polymethyl methacrylate, also known as methacrylic acid. In 1931, the United States began manufacturing acrylic resin to coat industrial machines and glass binders. Five years later, this resin was formed into a transparent sheet, and the acrylic era began. These acrylic sheets served as a useful bullet-resistant glazing on fighter planes during World War II, as it was light, strong and easily molded onto the skin of the aircraft. Plexiglass is unrivaled in its ability to withstand the weather and is unmatched by any other plastic glazing. In modern times, plexiglass is used for skylights, replacement windshields, protective blast shielding and bulletproof windows.

Cold Forming

Force the plexiglass into the desired shape. Note that the minimum radius of the bend you create is 180 times the thickness of the plexiglass sheet. For instance, the smallest complete circle you could form with a sheet of plexiglass 1/32 inch thick would have a radius of 5.6 inches. Attempting to create a smaller radius would snap the sheet.

Secure the plexiglass in place with round head wood screws.

Try heat forming for a more permanent and flexible method of plexiglass molding.

Heat Forming

Preheat the oven to 250 degrees F.

Place a plexiglass sheet on large pan and place on the middle oven rack. The large pan prevents the plexiglass from coming into contact with the hot rack, which can distort the plexiglass due to uneven heating.

Heat for approximately five minutes.

Pull the pan out of the oven with the cotton gloves. The heated plexiglass is now ready for molding.

Mold the plexiglass into the desired shape. Work quickly as the plexiglass will become less malleable as it cools.

Place your plexiglass in the refrigerator to set the shape. You can repeat this process as many times as needed.

Tip

Do not leave the plexiglass in the oven longer than seven to eight minutes, as this can result in melting. You only wish to soften the plexiglass with heat. For more precise molding, you can make a form out of wood in any size or shape and drape the softened plexiglass over it. When the plexiglass cools, it will maintain the form shape when removed.

Warning

Heating plastic must always been done with care, as melting plastic can cause serious injury.

About the Author

Aaron Kopf graduated from the University of Central Arkansas with honors in 2009, holding a Bachelor of Arts in communication. While enjoying his time at college, Kopf was published in The Echo and Vortex magazine.