How to Cut Plexiglass
Plexiglass is a kind of acrylic also known as Lucite or Polymethyl methacrylate (PMMA). While plexiglass can be applied to another surface as a coating or a resin, it’s often sold in sheet form as its clear appearance and light weight make it a durable substitute to actual glass.
However, cutting plexiglass to fit your individual windows or projects can be tricky. Even though it is more flexible than glass, it’s also more likely to splinter, chip, scratch, and even melt when handled or processed incorrectly. For this reason, proper cutting is essential. Refer to the following instructions to cut Plexiglas and get the best results.
Step 1 - Preparation
Begin by measuring the piece you want to cut out, using a measuring tape or ruler. Use a pencil and a straightedge to mark the line along which you will be cutting directly onto the larger sheet of plexiglass.
If you will be using a bench saw or circular saw, check the blade in the saw. If has medium or coarse teeth, change it to one that has fine, crosscut teeth. This will help prevent chipping as the blade cuts through the plastic sheet.
Step 2 – Choose the Right Saw
Because of the likelihood of the plastic melting due to the heat of a fast moving blade, you should use a scroll saw if you have one. This saw produces a low level of heat when compared with other options such as a band saw, table saw, or circular saw. A table saw works better if you're cutting your piece from a larger sheet of plexiglass, but be sure you use a blade with fine teeth--preferably one with at least 10 teeth per inch or finer. A plywood blade usually works well.
Step 3 – Use Safety Precautions
In addition to the obvious safety concerns that come with power saws, which can be mitigated by reading and following all user instructions, cutting plexiglass is dangerous in other ways.
In the event of splintering or chipping, loose shavings of plexiglass can be thrown by the saw blade and can become imbedded in your eyes or skin. To prevent this from happening, wear safety goggles, gloves, and a long-sleeve shirt when you are sawing the plastic.
Step 4 – Be Wary of Heat and Melting
As stated, the rapid motion of a spinning saw produces a high amount of heat, which is a problem because Plexiglas melts easily. The simplest solution here is to make sure you use a saw that has an adjustable speed, such as a jigsaw.
Use a slower speed to avoid melting of the plastic, and use a faster speed to avoid chipping. You may need to practice on a piece of the plexiglass you plan to discard. Find the best speed that will neither melt nor chip the plastic.
Another option to avoid melting the plastic is to use a spray bottle with water in it. As the saw blade slices through the plastic sheet, have someone direct a continuous spray of water onto the sheet where the blade cuts through the plastic.
Step 5 – Finish Up
Even with the most careful sawing, you will see rough or sharp edges on the piece you cut. You can smooth these edges with a fine grade of sandpaper.
However, this is a finishing touch. Your priority throughout the cutting project should be safely getting crisp, consistent cuts and edges.