How to cut acrylic at home

Key facts

• Score and snap: straight cuts in sheet up to 0.236 in. (6 mm); one stroke per 0.025 to 0.040 in. of thickness; strips narrower than about 1-1/2 in. don't break reliably (Trinseo).
• Circular saw blade: carbide-tipped, triple-chip grind, about 60 teeth on a 10 in. blade, low positive hook of 0° to 10° (Trinseo, Plaskolite).
• Saw feed: steady, about 3 to 4 in. per second on a table or panel saw (Trinseo).
• Jigsaw, scroll saw, band saw: 10 to 14 teeth per inch for thin sheet (Trinseo); 3 to 6 TPI skip-tooth band saw blades for 1/8 in. and thicker (Plaskolite).
• Router: 10,000 rpm or faster with a sharp two-flute bit 5/16 to 1/2 in. across (Trinseo).

Which method should you use?

How to score and snap acrylic

Scoring is the cleanest, quietest way to make straight cuts in thin sheet. Trinseo's Plexiglas guide limits it to sheet 0.236 in. (6 mm) and thinner, and to straight lines; the Perspex design guide is more cautious, at 4 mm (about 5/32 in.). It works best on 1/8 in. and 3/16 in., is doable on 1/4 in., and doesn't work on thicker sheet or patterned sheet.

1. Leave the film on and mark your line on it.
2. Clamp a straightedge along the line. A metal ruler or level works.
3. Score with a plastic scoring tool (the hooked blade sold for acrylic and laminate), not a utility knife. Pull it toward you with firm, even pressure, starting right at the far edge so the groove runs edge to edge.
4. Make enough passes. Trinseo's rule is one full-length stroke for every 0.025 to 0.040 in. of thickness: about 3 to 5 strokes for 1/8 in. and 6 to 10 for 1/4 in. A few extra light strokes don't hurt.
5. Snap it. Lay the sheet scored side up with the groove centered over a 3/4 in. wooden dowel running the full length of the cut. Hold the large side down with one hand and press the short side down with the other, hands close together, moving them along about 2 in. behind the break as it runs. Snapping over a table edge, scored side up and clamped, also works on smaller pieces.
6. Clean up the edge with a scraper or sandpaper. A snapped edge is a little rough at the bottom.

Cutting acrylic with a table saw or circular saw

A saw gives a clean, straight edge in any thickness. The blade is what matters:

• Use a triple-chip grind (TCG) carbide blade made for plastics or non-ferrous metals. Trinseo recommends the largest practical diameter with 60 carbide teeth; on a 7-1/4 in. circular saw, use the finest-tooth blade you can find. Don't use the blade on other materials, which dulls it.
• Keep the hook angle low. Trinseo calls for 5° to 10° positive rake; Plaskolite's cast sheet guide says 0° to 5°. Aggressive rip and framing blades (15° to 20° hook) grab and chip.
• Set the blade height. Trinseo's general guidance is about 1/2 in. of blade above the sheet to reduce chipping and heat; for extruded sheet it suggests only slightly above the surface. Try both on scrap.
• Support the sheet on both sides of the cut so it can't sag, vibrate, or pinch the blade. On a circular saw, put the sheet on a sacrificial foam board and cut through into it.
• Feed at a steady rate, about 3 to 4 in. per second per Trinseo. Too slow and friction heats the plastic until it melts and welds back together behind the blade. Too fast and it chips.

Rip blades and coarse framing blades will chip and crack acrylic. Cast acrylic saws more cleanly than extruded, which melts and gums up more easily (cast vs extruded acrylic).

Can you cut acrylic with a jigsaw?

Yes, with care, and it's the usual way to cut curves at home. It's also the tool most likely to crack the sheet.

• Use a fine-tooth blade for metal or plastic, 10 to 14 teeth per inch (Trinseo's figure for scroll and saber saws), not a wood blade.
• Run at medium speed. High speed melts the kerf closed and the blade binds. If it starts to weld behind the blade, back out, clear the chips, and let it cool.
• Support the sheet right next to the cut. Trinseo warns the saw's vibration can chip or crack the sheet, and suggests two layers of corrugated cardboard under it so the blade cuts into the board.
• Leave the masking on: Trinseo notes it lubricates the blade as well as protecting the faces.
• Don't force tight curves. Make relief cuts toward the line first.
• Expect a rough edge that needs filing and sanding.

A band saw does curves more smoothly if you have one. Plaskolite suggests 8 to 12 TPI for sheet under 1/8 in., 5 to 6 TPI skip-tooth for 1/8 to 1/4 in., and 3 to 4 TPI for thicker sheet. A band-sawn edge still needs scraping or sanding. Rotary tools with cut-off wheels mostly melt acrylic and aren't worth it for anything but small trims.

How to avoid chips, cracks, and melting

• Keep the film on until the part is finished. It protects the faces and reduces chipping at the top of the cut.
• Work at room temperature. Cold acrylic is more brittle. If it's been in a cold garage, let it warm up first.
• Don't cut close to an edge or close to holes. Leave material for the saw to bite.
• Melting means too much heat: slow down the blade, speed up the feed, or use a sharper blade. Trinseo says coolant isn't needed for most sawing, but a fine mist of water with a little detergent helps on thick sheet.
• Drill holes before cutting the part out so the larger sheet supports the drill. See how to drill acrylic without cracking it.

Safety

Wear safety glasses: acrylic chips are sharp and fly hard. Hearing protection helps with saws. Snapping can send a sharp shard off the break, so wear gloves when handling fresh edges. Don't try to cut acrylic with a hot knife or open flame.

Finishing the edge

A sawn or snapped edge is functional but cloudy. You can scrape, sand, and polish it: see how to polish acrylic edges.

When it's easier to order it cut

For a single straight cut in thin sheet, do it yourself. For thick sheet, curves, holes, many pieces, or edges that need to look finished, it's usually faster and cheaper overall to have it cut. Enter your sizes for acrylic cut to size or upload a drawing for laser cutting, and see the price instantly at the quote page.

Questions

Sources

• Trinseo: PLEXIGLAS acrylic sheet fabrication guide (cutting, scribing and breaking, routing)
• Plaskolite: OPTIX-L continuous cast acrylic sheet fabrication guide (cutting)
• Plaskolite: OPTIX acrylic sheet fabrication guide (band saw blades)
• Perspex: Design guide (cutting)
• Acrylite: Edge and surface finishing fabrication brief