When you need a clear plastic sheet, three materials dominate: acrylic (PMMA), polycarbonate (PC) and PETG. They look similar on the shelf but behave very differently in the workshop and in service. Choosing the wrong one can mean a part that cracks on installation, yellows in sunlight, or cannot be polished to the clarity you need.
Acrylic (PMMA)
Acrylic has the best optical clarity of the three — 92% light transmission, matching glass. It is the standard choice when visual quality matters: display cases, signage, picture framing, aquariums, lighting diffusers and anywhere you want crystal-clear transparency.
Acrylic is rigid and hard, which means it polishes beautifully and holds its clarity over time — it does not yellow with UV exposure the way polycarbonate does. The trade-off is that it is brittle under impact. A sharp blow will crack or shatter it rather than flex. It machines, laser cuts and engraves cleanly, and can be solvent-welded for invisible joints.
Strengths: Best clarity, UV stable, polishes to mirror finish, easy to machine and laser cut, solvent weldable, wide colour range.
Weaknesses: Brittle under impact, cracks rather than flexes, not suitable for safety glazing.
Polycarbonate (PC)
Polycarbonate is the tough option — roughly 200 times more impact-resistant than glass and 30 times stronger than acrylic. It is virtually unbreakable under normal conditions, which is why it is used for safety glasses, riot shields, machine guards and bullet-resistant glazing.
The trade-off is optical quality and UV stability. Polycarbonate has slightly lower clarity than acrylic (88% light transmission) and yellows with prolonged UV exposure unless treated with a UV-stabilising coating. It is also softer and scratches more easily than acrylic, and it cannot be polished to the same mirror finish. Polycarbonate is difficult to laser cut (it melts and discolours rather than cutting cleanly) and cannot be solvent-welded easily.
Strengths: Exceptional impact resistance, virtually unbreakable, good heat resistance, flexible enough to cold-bend.
Weaknesses: Yellows with UV, scratches easily, lower clarity than acrylic, poor laser cutting results, limited colour range.
PETG
PETG (polyethylene terephthalate glycol-modified) sits between acrylic and polycarbonate in most properties. It is tougher than acrylic but not as impact-resistant as polycarbonate. Its clarity is good (around 90% transmission) but not quite as crisp as acrylic. It does not yellow with UV and is FDA-approved for food contact, making it common in food packaging and display.
PETG is the easiest of the three to thermoform (heat and bend into shapes), which makes it popular for vacuum forming, blister packaging and curved displays. It cuts cleanly on a bandsaw and can be laser cut, though the edge quality is not as clean as acrylic. It cannot be solvent-welded — adhesive bonding is required for joints.
Strengths: Good balance of clarity and toughness, UV stable, excellent thermoforming, food-safe, chemical resistant.
Weaknesses: Slightly lower clarity than acrylic, softer surface, cannot be solvent-welded, not as impact-resistant as polycarbonate.
Quick comparison
For display, signage and visual quality: Acrylic. Nothing matches its clarity and polish.
For safety, impact resistance and machine guarding: Polycarbonate. It will not shatter under impact.
For thermoforming and food contact: PETG. Best formability and food-safe certification.
For laser cutting: Acrylic (cast). Clean cuts with polished edges. Polycarbonate and PETG both give poor laser results.
For outdoor use: Acrylic or PETG. Both are UV-stable without additional coating. Polycarbonate yellows without UV treatment.
For budget projects: PETG is generally the cheapest. Acrylic and polycarbonate are similar in price, with polycarbonate slightly higher.
