Plexiglas is a type of acrylic that's strong and durable, so it won't break as easily as other types of plastic would (like vinyl). The stability in plexiglass also depends on the thickness; for safety purposes, acrylic panels that measure over one square meter should have at least four millimeters. If Plexi gel contains more than six millimeters, you'll need to use silicone adhesive or screws to join them together.