how to work our acrylic sheets
What is Acrylic?
Acrylic is a clear plastic that closely resembles glass but has many advantages, making it in excellent substitute in many applications. Compared to glass, acrylic is:
– Lighter in weight by half
– Stronger and more impact resistant
– Offers better insulating properties
– More transparent
Acrylic does have two main disadvantages compared to glass: it’s more expensive and it can melt and burn if exposed to a direct flame. Because it doesn’t transfer heat well, special care needs to be taken when working with acrylic to avoid creating heat, which may cause stress that can lead to crazing.
How to Cut Acrylic
Acrylic comes with a protective masking on both sides. Keep the masking on for as long as possible throughout the fabrication process to protect the finish.
There are several ways to cut acrylic, but regardless of which method you use, you will want to prevent your cutting tools from becoming a source of damaging heat. One method is to use a table saw, preferably with a carbide-type blade with 10 teeth per inch. Acrylic can also be cut with a CNR router, a CO2 laser or a water jet. Note that each cutting method will create a different edge finish.
Choose a saw blade that is designed for cutting acrylic. The blade’s teeth should be fine, of the same height, evenly spaced, with little or no set. Be sure to feed the acrylic into the saw blade at a steady rate — feeding it too fast or too slow can cause the edge of the material to melt.
Thin pieces of acrylic (1/8″ or less in thickness) can be scored like glass using a scribing knife, metal scriber, awl or utility knife, and snapped apart. Note that this process does not work well for long cuts and may not leave an edge that is flat enough for capillary gluing.
How to Drill Acrylic
Acrylic can be drilled successfully but there are two situations you need to avoid: creating heat and twisting the material. Heat generated by a drill can cause the acrylic to melt or crack, and any twisting or grabbing by the drill bit can cause the material to fracture.
A normal twist drill can be modified for use on acrylic with a bench grinder. Use specially-ground and polished drill bits that are designed for use with acrylic. You can modify the bit by grinding small flats onto both cutting edges, so the bit cuts with a scraping action. If the drill is correctly sharpened and operated at the correct speed, a long curly strand of acrylic will be created during the drilling process.
Drill speed is an important factor. Set the drill press from 500 to1000 RPM. Always begin and end the drilling of holes at a slow-feed rate. If you are drilling a series of holes, allow the bit to cool off from time to time to avoid heating the acrylic.
A piece of plywood can be placed behind the acrylic to give the exiting drill bit something to dig into and prevent it from grabbing the acrylic as the drill speed winds down. To prevent cracking the edge of the acrylic sheet, do not drill too close to the edge (1.5 times the diameter of the hole measured from the center would be considered “too close”).
How to Finish Acrylic Edges
Several factors will determine how well you need to finish the edges of your acrylic pieces: how the project is going to be used, if the joints will be glued, the type of glue you plan to use, and the type of joint desired. During the early planning stages of your project, remember that choosing the right saw blade for your initial cuts can greatly minimize the amount of edge finishing needed down the road.
There are several methods for finishing the edges of a piece of acrylic.
How to Glue Acrylic
Solvent cements are recommended to create strong, transparent and durable joints on acrylic pieces. When using solvent cements, always work in a well-ventilated area away from heat or flames. Wear protective goggles and clothing and follow the manufacturer’s instructions.
Capillary cementing is the most popular method for joining acrylic. To create perfect joints, make sure that all surfaces that will be joined together fit without force and are flat, straight and clean. Hold the pieces together using masking tape or a clamp and keep the joint in a horizontal plane so the cement doesn’t run out.
Apply the cement carefully along the entire joint. For box-corner joints, apply the cement from the inside edge. On flat joints, apply the cement on both sides if possible.
For best results, use a needle-nosed applicator bottle. Allow the joint to set for about 30 minutes before moving the joined pieces. Note that maximum bond strength takes 24 to 48 hours.