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To cut plexiglass leave the the paper on and lay the sheet to be cut on a flat, even surface. Using a yardstick and a grease pencil mark the sizes of the pieces to be cut on the paper. When this is complete use a glass cutter to score the lines. It is wise to use the yardstick as a straight edge to follow while doing this and to score the lines 5 to 10 times. When the lines are scored place the scored line on the edge of the table and apply a sharp, downward pressure until the pieces snap in two. To smooth the edges on plexiglass that is thicker than 18 inch, clamp the piece to a table surface and use a power saw leaving only enough overhang for the saw blade clearance. On thicker sheets of plastic you can also use a drill that is fitted with a buffer to smooth the edges. Be sure to coat the pad with either tripoli or rouge polishing compound before you buff. Finish the edges with a non-stitched disc of clean muslin or flannel and do not buff after you have seamed. Larger pieces of plexiglass can be cut using a table or power saw. Be sure it is firmly clamped down prior to cutting to keep the plastic from shifting. It is wise to use a power saw for cutting the thicker sheets of plexiglass only. Thin sheets should be cut using a glass cutter to keep them from chipping. Curved areas can be sanded or polished by using an electric drill with a small rotary tool that is specified for working with acrylic. Holes should be drilled using a portable drill or drill press that is set to low speed. Twist bits for metal work well on plexiglass but for the best results you should buy a specially ground twist bit from a plastics supplier. Be sure you only apply light pressure when drilling and support the work with a scrap of wood.