Material guide
Acrylic (plexiglass)
What works on acrylic and plexiglass: the right drill bit and speed, blade, solvent cement, screw holes that won't crack, and how to polish a clear edge.
Quick facts
- Best drill bit
- A bit made for plastic: 60 to 90° point, cutting edge ground flat (0 to 4° rake) so it scrapes, not grabs
- Drill speed
- About 1,800 rpm for a 1/4 in bit and 900 rpm for 1/2 in. Back the sheet with scrap.
- Best blade
- Carbide, triple-chip teeth, kept for plastic only. On a 10 in table saw, 80 teeth.
- Score and snap
- Only for sheet thinner than 0.118 in (3 mm). Saw anything thicker.
- Best glue
- Solvent cement, run into the joint. Full strength takes 24 to 48 hours.
- Screw holes
- Drill bolt holes at least 2x the bolt size. Keep the hole center 1.5x the hole size from the edge.
Acrylic is a clear, rigid plastic. You'll see it sold as plexiglass, Plexiglas, Acrylite or Lucite. It's lighter than glass and much harder to shatter, but it scratches more easily.
Acrylic is easy to work if you respect two things. First, it's brittle under a point load. A normal drill bit grabs the sheet as it breaks through and cracks it. Second, it softens with heat. A dull blade or a slow feed melts the edge, and the chips weld back on.
So the tricks are about cutting cleanly and staying cool. Use sharp tools made for plastic. Leave the protective film on. Clamp the sheet so it can't flex or chatter.
Acrylic also reacts to some chemicals. Ammonia window cleaner, acetone and gasoline can cause crazing, a web of fine cracks. Clean it with mild soap and water, or a cleaner made for acrylic.
Drill into acrylic (plexiglass)
Use a bit made for plastic, or one ground to a flat edge. A normal twist bit grabs and cracks the sheet. Clamp the sheet over scrap, leave the film on and drill at a moderate speed. Slow the feed as the bit exits. Melted chips mean too fast.
What to use: Plastic drill bit set
Guides
- How to drill acrylic (plexiglass) without cracking it (coming)
- Best drill bit for acrylic (why zero-rake matters) (coming)
Cut acrylic (plexiglass)
Thin sheet under 0.118 in (3 mm): score it several times and snap it over an edge. Thicker sheet: use a carbide blade with triple-chip teeth, kept just for plastic. Clamp the sheet, leave the film on and feed steadily so the edge doesn't melt or chip.
What to use: Triple-chip carbide blade, plastic only
Guides
- How to cut plexiglass with a circular saw
- How to cut a circle with a jigsaw (or a router)
- Table saw vs miter saw vs chop saw: which one do you need?
- What is a panel saw?
- What blade to cut up a hot tub (and how to do it safely)
- How to cut plexiglass (with a circular saw, jigsaw, or score-and-snap) (coming)
- What blade cuts acrylic without melting or chipping (coming)
- Circular saw blade guide: tooth count, kerf, and which blade for what (coming)
- Jigsaw blade types: T-shank, TPI, and down-cut (coming)
Glue acrylic (plexiglass)
For acrylic to acrylic, use a thin solvent cement. It melts the two faces together. Tape the parts square and run the cement into the seam. It grabs in seconds, but wait three hours before you work on it. Don't cement a polished edge, or it may craze.
What to use: Thin solvent cement + needle applicator
Guides
- Best glue for acrylic: solvent cement vs super glue vs epoxy (coming)
- Super glue clouded my acrylic: why, and how to avoid it (coming)
- How to remove super glue from glass, plastic, and skin (coming)
Screw or anchor into acrylic (plexiglass)
Acrylic grows and shrinks with heat, up to 1/16 in per foot. So drill holes bigger than the screw, and keep them away from the edge. Use round-head screws with a smooth shank and a washer. Skip countersunk screws and drywall screws, which crack it.
What to use: Round-head screws + rubber washers
Guides
- Types of screws: the 14 you'll actually meet (and what each is for) (coming)
Sand or finish acrylic (plexiglass)
Scrape the saw marks off the edge with a sharp scraper. Then wet sand from 180 to 320 grit, and up to 600 for a finer finish. Buff with a cloth wheel and compound for a clear edge. Use light pressure, since heat softens acrylic.
What to use: Edge scraper + wet-or-dry paper
Guides
- Polish acrylic edges to clear (coming)
- Sandpaper grit chart: which grit for which job (coming)
Safety basics
- Wear safety glasses. Chips fly off saws and bits, and a cracking sheet throws sharp pieces.
- Clamp the sheet. A bit that grabs can spin the sheet in your hands.
- Air out solvent cement. It gives off strong vapors and may be flammable. Work with a window open and no flame nearby.
- Keep the saw guard on. Plastic can bind and kick back just like wood.
Sources
- Drilling ACRYLITE acrylic sheet: 60-90° point, 0-4° rake, backing board, slow feed at exit, hole spacing from edge, bolt holes 2x bolt diameter (ACRYLITE)
- Drilling plastic: suggested drill speeds, backing board, expansion up to 1/16 in per foot, round-head screws, no drywall or countersunk screws (TAP Plastics)
- What types of circular saw blades are used for cutting acrylic sheet: carbide, triple-chip, 80 teeth on 10 in, 0-10° hook (ACRYLITE)
- ACRYLITE extruded sheet fabrication brief #3: other methods of cutting, scribe and break under 0.118 in (ACRYLITE)
- Cementing ACRYLITE: capillary method, don't polish edges to be cemented, 3 h before processing, high strength in 24-48 h, ventilation (ACRYLITE)
- Finishing ACRYLITE acrylic sheet: scraping, wet sanding 180-320 grit, 400 and 600 grit, buffing, flame polishing and crazing (ACRYLITE)
- Clean, disinfect and maintain ACRYLITE sheet: wipes that scratch or craze the surface (ACRYLITE)
- How to maintain acrylic sheeting: never use ammonia, acetone or gasoline (AC Plastics)
- LOCTITE Super Glue Gel technical data sheet: bonds hard plastics such as acrylic (Henkel)