Cast acrylic is the most optically clear and harder than Extruded acrylic but has more variation in thickness and is more expensive. However, for framing work the thickness variation is not something that would normally be a problem. It is made by pouring liquid plastic into an individual mould for each sheet, consisting of 2 sheets of glass separated and sealed by a gasket. The plastic is then cured and the mould taken apart to release the sheet. We would recommend using Cast acrylic for all work using 3mm thickness and above as it gives a more optically clear plastic with a harder surface.
If the sheet needs to be milled or drilled Cast is preferable as Extruded is more likely to melt during the process particularly on thicker grades.
We have given a price for a 20 by 16 inches sheet. For a quotation on a different size, please call us.