Short answer: Acrylic is the clearest (92% light transmission), most weather-resistant, and most laser-friendly of the common plastic sheets, which makes it the standard for signs, displays, and precise clear parts. HDPE is tough, slippery, and food-friendly but opaque, hard to glue, and moves about 1.7 times as much with temperature; polycarbonate and PETG are tougher but less clear; ABS, Delrin, and PVC are opaque engineering and sign plastics. PVC must never be laser cut: university laser safety rules ban it because it releases corrosive chlorine-based gas.
Plastic sheet comparison chart
| Plastic | Clarity | Toughness | CO2 laser cutting | Outdoors | Relative cost | Typical uses |
|---|---|---|---|---|---|---|
| Acrylic (PMMA) | Excellent, 92% | Moderate; several times glass, can crack or chip | Excellent: glossy edges, clean engraving | Excellent | Medium | Signs, displays, frames, cases, covers, windows |
| Polycarbonate (PC) | Very good, about 86 to 88% | Very high; about 27 times acrylic in Plaskolite's impact test | Poor: over 1 mm cuts poorly, discolors, may ignite | Good with UV-protected grades | Higher | Machine guards, security glazing, greenhouses |
| PETG | Very good, about 86% | High; about 4 to 6 times acrylic's notched impact | Poor: melts, rough edges | Fair; mostly indoor grades | Medium | Face shields, vacuum forming, retail displays |
| HDPE | Opaque or milky | Very high; flexes | Banned in many labs: melts and may ignite; usually routed | Good with UV-stabilized grades | Low to medium | Cutting boards, marine parts, liners, chemical tanks |
| PVC | Mostly opaque; some clear grades | Moderate to high | Never: releases chlorine-based gas | Fair to good, varies by type | Low | Foam sign board, trim, pipe, panels |
| ABS | Opaque | High | Banned in many labs: melts, releases cyanide-containing fumes | Poor unless capped or UV-protected | Low to medium | Enclosures, vacuum-formed parts, automotive trim |
| Delrin (acetal, POM) | Opaque | High; stiff and slippery | Cuts, but releases formaldehyde; strong ventilation, and many labs restrict it | Fair | High | Gears, bushings, slides, jigs, wear parts |
| Polystyrene (PS) | Clear or opaque grades | Low; brittle when clear | Poor; foam versions are a leading cause of laser fires | Poor; yellows | Lowest | Cheap frame fronts, models, packaging |
These are general behaviors from maker data sheets and university laser safety guidance. Each plastic comes in many grades, and properties and prices vary by manufacturer, thickness, and market.
Caution: never laser cut PVC or vinyl, including adhesive vinyl, faux leather, and foam PVC sign board. The University of Illinois lists PVC as a do-not-cut material because it can emit chlorine gas; the chlorine-based fumes (mainly hydrogen chloride) form hydrochloric acid with moisture, which harms your lungs and corrodes the laser. Illinois also lists ABS, HDPE, polycarbonate over 1 mm, and polystyrene foam as do-not-cut. If you don't know what a plastic is, don't put it in a laser.
Acrylic vs HDPE
These two are close to opposites. HDPE (high-density polyethylene) is waxy, flexible, nearly impossible to crack, and slippery (INEOS lists a friction coefficient of 0.29), and many grades are made for food contact. That's why it's used for cutting boards, marine hardware, and slides. It's also light enough to float, at 0.93 to 0.965 g/cm³ vs 1.19 for acrylic. But it's opaque or milky, it scratches and gouges easily, and almost no glue sticks to it well; it's usually joined with screws or by welding. It also moves a lot with temperature: about 6.7 × 10⁻⁵ in./in./°F, roughly 1.7 times acrylic.
Acrylic is rigid (flexural modulus about 475,000 psi vs about 150,000 psi for HDPE), clear, glossy, and easy to glue into clean joints. It's the better choice for anything people look at or through. For cutting boards and parts that rub, slide, or get hit, HDPE is the right material, and acrylic isn't. Standard sign-grade acrylic isn't certified for food contact, either. See is acrylic food safe.
Acrylic vs polycarbonate and PETG
These are the other two common clear sheets. Both are much tougher than acrylic and both bend more before breaking, but both are less clear (about 86% vs 92% in Plaskolite's data), scratch more easily, don't laser cut cleanly, and don't polish to acrylic's glass-like edge. Read the full comparisons: acrylic vs polycarbonate and acrylic vs PETG.
Acrylic vs PVC
Rigid and foam PVC are inexpensive and common in sign shops for printed signs and displays, and PVC weathers reasonably well. It's mostly opaque, though, and has a matte, plastic look next to acrylic's gloss. Clear PVC exists but has a faint tint and isn't as clear. The deciding factor for us is that PVC can't go under a laser at all, so it's routed or knife cut. For a premium sign, acrylic looks far better.
Acrylic vs ABS
ABS is tough, opaque, and easy to vacuum form, which is why it's used for enclosures, luggage, and automotive parts. It isn't clear, it fades and gets brittle in sun unless it's protected, and it shouldn't be laser cut: it melts into a gummy edge and university labs ban it for its cyanide-containing fumes. For a clear or laser-cut enclosure, acrylic is the usual choice. See acrylic electronics enclosures.
Acrylic vs Delrin
Delrin is a brand of acetal (POM), an engineering plastic prized for being stiff, strong, low-friction, and wear resistant. It's what you want for gears, bushings, and sliding parts. It's opaque and costs more than acrylic. For moving, rubbing, or load-bearing mechanical parts, Delrin beats acrylic. For clear covers, panels, and display parts, acrylic wins.
Acrylic vs polystyrene
Clear polystyrene is the thin, inexpensive “glass” in many budget picture frames. It's clear at first, but it's brittle, scratches easily, and yellows faster than acrylic in sunlight. If a cheap frame front has cracked or yellowed, it was probably polystyrene. Acrylic is a clear upgrade.
Why acrylic is the laser-cutting plastic
Under a CO2 laser, acrylic vaporizes cleanly instead of melting or charring: Acrylite describes the result as a clean, polished edge with a narrow kerf that lets parts nest closely. Engraving leaves a crisp frosted mark. Few other plastics behave this way. That's why laser-cut signs, displays, jewelry, and parts are almost always acrylic. Can you laser cut acrylic? and are laser-cut acrylic fumes toxic?
If acrylic fits your project, we'll cut, polish, drill, or bend it for you. Describe it on make it in acrylic or see your price instantly in the instant quote.
Questions
How can I tell what kind of plastic sheet I have?
Look for a printed film, label, or recycling code first. Without one, you often can't tell safely by looking, which is exactly why unknown plastics should never be laser cut or burn tested indoors.
Can I make a cutting board from acrylic?
No. Knives scratch acrylic badly and can chip it, and standard sheet isn't certified for food contact. Use HDPE or wood. Acrylic works well for serving trays and lids for dry, room-temperature food if you choose a food-contact grade.
What's the cheapest clear plastic sheet?
Polystyrene, but it's brittle and yellows. Extruded acrylic is the best value for clear parts that need to look good and last.
Does HDPE float, and does acrylic?
HDPE floats in water (density 0.93 to 0.965 g/cm³). Acrylic sinks (1.19 g/cm³), as do polycarbonate (1.20) and PETG (1.27).