Daughter Igorette has a new hobby: hermit crabs. Being the good father that I am, I suggested that I could make a container for her. We bought a sheet of plexiglass that I now have to cut. The cuts are going to be one 48", and several 11.5" cuts. Not having worked with Plexiglass before, I don’t know what’s it’s like to work with. At my disposal are a small 10" table saw and a hand-held B&D reciprocating saw that could be mounted upside down below a plywood sheet with a hole in it. What kinds of blades could I use that won’t shatter the material? Do I need slow speed, or will table-saw speeds be ok?
I use a Dremel moto-tool, although I’m not sure this will be a worthwhile solution; a Dremel, along with the cutting wheels it uses, will run you around a hundred bucks.
I don’t know how thick your sheet of plexiglass is, but for thinner sheets you can get a special scoring tool at home depot or lowes or similar places. Score the plexiglass along the line where you want it to cut, then snap it over a table edge. Some people think you can just score it once along the line and it will snap. It probably won’t. You are going to have to go over the score a bunch of times until you have a reasonably deep score line. Then it will snap easily.
For thicker pieces you can use your table saw, but feed the plexiglass slowly.
A reciprocating saw mounted upside down seems like an awfully dangerous idea to me.
A table saw will do the job. You want a crosscut blade, example, and not one with big clunky welded on carbide teeth that project way past the plane of the disk. Those projections can cause cracks.
A ripping blade will chop out too much plastic too fast, and again cause cracks. One of those thin plastic cutting blades will wander off a straight line, and also cause excessive frictional melting.
Regular speed seems to work best. There’ll be some melted flash on the cut, but in my hands, decreasing rpm leads to trouble with cracks (maybe if I cut way down on feed rate…?). For fine scale work I use a rotozip.
I’ve tried reciprocating saws on the stuff, but the blades lack the strength needed to maintain a neat, straight cut. That’s bad if you want to glue the pieces together afterwards.
Shop Tip:
When cutting plexiglass on the bandsaw or scrollsaw leave the protective plastic sheet on the workpiece. It lubricates the blade and prevents the plexiglass from melting.
I would try a carbide tipped scoring knife first, like the kind we use to cut tilebacker board.
If it’s too thick to score, the table saw will work fine, especially with a plywood type blade (the ones with a bunch of small teeth) You might also tape both sides of the cut line, this will give a cleaner cut. As was said, PLEASE do not try to mount a sawzall (our generic trade term for any recip saw) in any type of jig thing. VERY dangerous!
Also, if using the table saw, make sure the plexi stays flat on the table as you cut. Unlike thicker wood, if it bows/flops up a bit, the blade will surely catch it and shatter the shit out of it.
Go slow, and if it feels like it’s binding, back up a bit and then continue, you would not believe how easy that stuff will shatter. I would wear a full face shield when cutting, not just safety glasses.
I’ve worked with acrylic for years and would second DMC’s link for basic information. My question would be: how are you planning on joining the edges in the container? If you’re going to use some sort of metal angle or extrusion to hold the faces together you have a fair amount of leeway in your choice of table saw blade. Any chips along the edges you get from using the average combination blade in a table saw will be hidden when the pieces are assembled.
If you plan on using a solvent adhesive, however, it’ll be worth your while to pony up the money for a blade that will give you a really nice cut, unless you already have one. Solvent adhesives require a really smooth finish on the edges and sanding a rough cut down to really smooth is a pain in the neck.
If your fingers are loose, then the whole project might be too difficult, but yeah, keep gloves away from the saw blade because, y’know, they’ve got your hands inside them. For the same reason, keep your shoes away from the blade, unless you take them off your feet.