Cast or Extruded Acrylic Sheet? How They Differ

Cast acrylic (GS) is made by polymerising liquid MMA between glass plates. Extruded acrylic (XT) is made by melting polymer granules and drawing the sheet through a die. Cast sheet has a higher molecular weight, so it machines, forms and engraves well. Extruded sheet has a tighter thickness tolerance, is usually cheaper and bonds more easily with solvent cement. Both are sold as “plexiglass”.

Comparison

	Cast (GS)	Extruded (XT)
Production	Polymerised between glass	Extrusion
Thickness tolerance	Wider variation	Tighter tolerance
Laser cutting	Flame-polished edge, high-contrast engraving	Economical for volume work
Forming	Wide temperature window	Narrower window
Bonding	Reactive adhesives	Solvent cement works easily
Clarity and weathering	Small difference	Small difference
Cost (general)	Usually higher	Usually lower

Laser cutting and bonding

The laser maker eurolaser says cast sheet gives flame-polished cut edges and suits high-contrast engraving, while extruded sheet has tighter thickness tolerances and is often the more economical choice for higher volumes. Our product page also notes that a smooth, glossy edge is possible with laser cutting.

Röhm’s joining guide says extruded XT responds more readily to solvent action, while polymerisation (reactive) adhesives are recommended for cast GS; pure solvents without added polymer do not work well on GS. Solvent adhesives are flammable and their vapours are harmful, so work in a ventilated place.

Which one for which job?

• Cast: letters, thick blocks, engraving, parts to be formed, milled work.
• Extruded: series laser cutting, flat partitions, shelves, lightbox faces and parts needing a steady thickness.

Our products

• Cast acrylic sheets: 1 to 40 mm.
• Extruded acrylic sheets: tighter size and thickness tolerance.
• Acrylic plexiglass sheet: 2 to 50 mm.

For acrylic versus polycarbonate, see acrylic or polycarbonate sheet. For price and stock, ask your branch or contact us.

FAQ

Cast or extruded for laser cutting?

Both can be laser cut. Cast gives a flame-polished edge and strong engraving contrast; extruded offers steady thickness and lower cost on series work. Test first.

Which is clearer?

The difference is small. Clear sheet of either type is transparent and naturally UV-stable.

Which is cheaper?

Extruded sheet is generally cheaper. Thickness, colour and brand also matter; ask your branch for current prices.

Sources: PLEXIGLAS joining guide, eurolaser.

This article contains general information; confirm dimensions and technical values before production.