View Full Version : Cutting plexiglass??

Fred Voorhees
08-24-2010, 7:08 PM
I have this guy who wants me to build some rather large, simple frames for some old signs from a now defunct race track. I will be buying a 4X8 sheet of 1/4" plexiglass and I will naturally need to cut it into the sizes I need. I was thinking of using a very fine tooth saber saw blade. I think I have done that in the past with relative luck, but I thought I would check with the pool of experts on UJ for some handy information. I'm assuming that the plexiglass will come with a protective plastic film on both sides, and I will tape the cut lines to further help in producing a nice cut, but is there anything else I might do to mitigate any fracturing along the cut line or is there any better advice? Would appreciate it guys. Thanks

Fred Voorhees
08-24-2010, 7:11 PM
Don't know what the heck was on my mind when I typed "UJ". I meant to type SMC. Anyway, appreciate some help.

Dan Friedrichs
08-24-2010, 7:17 PM
You can do it with a fine-tooth blade on the tablesaw, or using a band saw. Rough edges can be cleaned up using a belt sander, or a propane torch.

Joe Chritz
08-24-2010, 7:25 PM
They make blades just for cutting plastics but if you are just doing one sheet a fine tooth tablesaw blade will do just fine.

Like Dan said you can wave a torch over the edges and they clean right up.


Dan Hintz
08-24-2010, 7:48 PM
If you do decide to get a blade meant for this, find one with a few degrees negative rake to avoid chipping.

Fred Voorhees
08-24-2010, 7:51 PM
All good advice....thanks guys!

Stephen Tashiro
08-24-2010, 8:09 PM
Is there a difference between "plexiglass" and the other sheets of clear plastic available in hardware stores. Cutting the stuff from the local hardware store left so many fragments of melted plastic inside my circular saw guard that the blade jammed. It was an old saw and I expected this. It wasn't hard to clean out.

Tom Winship
08-24-2010, 8:12 PM
I have had success scoring it and breaking it over an edge (like glass). There is a learning curve, tho.

Joe Chritz
08-24-2010, 8:57 PM
There are two main types that I have used. Cast and extruded. The cast is great for laser engraving. I would imagine that different brands have different quality levels.

Stephen I assume the melted plastic was from the blade. The only real difference with a plastic blade is the negative hook angle and usually relieving the sides so they don't rub and cause heet.


David G Baker
08-24-2010, 9:18 PM
Lexan is another plastic sold in Borgs and hardware stores. I cut Lexan with a scoring tool designed for it and snap it over an edge like cutting glass. It tends to chip and sometimes shatters when cut on a table saw. Plexiglas I use a blade designed for it and run it through my table saw.

Jim O'Dell
08-24-2010, 10:05 PM
I have what I think is some plexiglass, about 1/4" maybe slightly thicker but no more that 3/8" I have a 60 tooth plastics/laminate blade I use. Works great. I cut curves on the BS with a 1/4" 7 TPI (IIRC) blade. Also worked very well. My TS blade is a triple chip style blade and cut very cleanly. Worth the bucks it you are doing some long straight cuts. Mines a Systimatic I got off of Ebay years ago, I think from Cripe Distributing. It was about $40.00. Jim.

Zach England
08-24-2010, 11:14 PM
I have had success cutting thicker plexi on a TS with a melamine blade. When I tried to cut thinner plexi it ended up very rough.

It stinks and makes a mess.

Steve knight
08-25-2010, 12:00 AM
the difference between cast and extruded in milling is pretty large. the stuff at the borg is extruded. it chips and shatters and melts. cast will cut cleaner and will not usually melt.
I machine it on my cnc router all of the time.

Jim Becker
08-31-2010, 9:27 PM
Fred, I've cut Plexi and Lexan on my table saw and on my band saw. Heat can be a problem with cutting plastic. Ideally, a "for plastic" blade will give best results, but I just used my normal blades.

jerry nazard
08-31-2010, 10:38 PM
If you cut on the TS, keeping the blade height just above the plexi will minimize the amount of plastic that melts and clogs the blade.

Richard M. Wolfe
08-31-2010, 11:18 PM
I've had no problems cutting it with a table saw using a general purpose sixty tooth blade. I had some one time that chipped pretty badly and what worked was to raise the blade just above the table surface, score one side, flip it, score the other side and then break it.