Steps
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1.Check the thickness
Scoring and snapping works best on sheet up to about 5mm. Thicker sheet needs too many passes and is likely to break off-line, so saw it instead.
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2.Clamp a straight edge
Leave the protective film on. Clamp the steel rule along your line so it cannot move while you score.
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3.Score repeatedly
Draw the scoring knife along the rule with firm, even pressure, five to ten times on thin sheet, until the groove is about a third of the thickness deep.
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4.Snap over the bench edge
Line the score up with the edge of the bench, score side up. Hold the sheet flat on the bench and press down sharply on the overhanging side. It breaks along the score.
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5.Clean up the edge
Scrape or sand the snapped edge to remove the sharp lip.
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6.Drilling
Use a drill bit ground for plastics (or blunt the cutting edge of a standard bit slightly), drill slowly with light pressure, and back the sheet with scrap timber so the bit does not grab and crack it as it breaks through.
Tips
- Cast acrylic (which Perspex is) scores and snaps cleanly; extruded acrylic is a little softer and can melt more readily under a saw.
- Keep holes at least twice the sheet thickness away from the edge.
- Never score towards your hand.
Drilling Perspex without cracking it
Cracks start where a bit grabs or the sheet flexes. Clamp the Perspex flat on scrap timber, use a bit made for plastics or a standard bit with its cutting edge dulled slightly, and drill slowly with light pressure. A small pilot hole first, then the full size, is kinder to thin sheet. Keep holes back from the edge, and drill oversized holes for anything fixed outdoors so the sheet can move.
Cleaning and removing scratches
Wash Perspex with warm soapy water and a soft cloth, rinse and blot dry. Avoid paper towels, ammonia and solvent cleaners. Light surface scratches polish out with a plastics polish; deeper ones need wet-sanding with fine grits, about 800 up to 2000, before polishing back to a gloss.