Cast vs extruded acrylic - which one should you actually buy?
Side-by-side comparison of cast and extruded acrylic across machining, optics, cost and the jobs each is genuinely best for.
Cast and extruded acrylic look identical on the rack - and most distributors sell them at the same price. They are not the same material. Picking the wrong one will cost you in scrap, polish time and customer complaints.
Cast acrylic - the premium choice
Cast acrylic is poured between two glass plates and cured slowly. The result is a higher molecular weight polymer with better optical clarity, better thermoforming behaviour and far better machinability. Edges flame-polish to optical quality. It costs 15–30% more than extruded.
Use cast for: laser-cut signage, edge-lit displays, pool windows, aquariums, anything that gets machined or flame-polished, and anywhere the finished part needs to look perfect.
Extruded acrylic - the budget workhorse
Extruded acrylic is squeezed through a die. The polymer chains end up aligned in the direction of extrusion, which makes the sheet cheaper but more prone to crazing when laser-cut, less stable when thermoformed, and harder to flame-polish cleanly.
Use extruded for: routine glazing, sneeze guards, machine guards, anywhere the part is bandsaw-cut and screwed in place without further finishing.
Quick rule of thumb
If the finished edge will be visible - buy cast. If the part will be hidden behind a frame - extruded saves you money.