How does one go about cutting 1/4 plexi without ruining it cause i just picked up three rather large pieces for ten bucks a peice they are 30"x65"x.25"
The problem with cutting plexiglass is the heat generated by whatever you're using to cut it with... so slow and easy is the way to cut it. I have also used running water to help keep the temp down while cutting with a power tool (jig saw, dremel, etc...).
I cut mine with a table saw with a really nice sharp blade. For curves use a jigsaw as mentioned above. Go nice and slow and it should minimize chipping. Good luck
If you can get your hands on one, a Rotozip does a quick job cutting plexi, without a lot of the problems you'd experience with a circular (table) saw or jigsaw. Only problem is cutting straight lines freehand, but a simple fence (for straight lines) or jig (for cutting curves) is easy to use with it. If you need circles, they make a nice compass style attachment for it too!
If you do melt a section, sand it good and use any blue flamed torch or cigarette lighter to make the edges crystal clear, like glass. It MUST be a blue flame or the plexi will turn black.
You'd probably be better off sanding up to something like 600 grit on the edge and then using a Novus #2 fine scratch remover/polish. Flame stuff isn't for noobs and can easily damage the piece. I'd only try the flame on a few scrap pieces before using it on something you don't want to mess up.
a) use a blade (whether sabre saw or jigsaw) meant to cut plastics, regular blades cause a lot of heat so the plastic many times gets melted back together behind the blade during the cut
b) sandwich the piece to be cut between some scrap plywood with some clamps, this helps reduce vibrations in thinner pieces to prevent cracking in the vicinity of the cutting area