The Best Way to Cut Plexi-Glass

[Sean Wright]

My Dad asked me today what the best way of cutting plexi-glass is.

I have cut it with on my table saw(60 tooth carbide blade) and with a jig saw (fast wood blade). Neither one would be what I would consider to be the best way. Using both saws, the chips would melt together into globs. Not to mention that it stunk up my house pretty bad (basement shop). My wife asked me what I was burning down there.

My Dad said that he heard something about putting the saw blade in backwards for cutting plexi, but he has never dared to try it.

What kind of suggestions does everyone have? Certain type of saw, certain type of blade, etc.......

Thanks

[Kerry Burton]

I'm no expert, but I recently cut several rectangles of thin (.093"?) acrylic from larger sheets with my low-budget Black & Decker circular saw and one of those self-locking edge guides. I used a fairly nice blade (thin kerf, can't remember how many carbide teeth) but I also sandwiched the acrylic between hardboard. It worked pretty well.

I'd like to hear how the REAL experts do it....

[Jim O'Dell]

I think the idea with plastics is to carry the cut pieces away so they don't weld back together. Therefore a bandsaw with a fine blade, 7 tpi or more, would be what I would try. Hopefully the plastic would cool off by the time it got back around if it was still in the gullet of the blade, and better yet it gets knocked off and into the dc. Jim.

[Bill Simpson]

Cut Plexyglass the same as you cut glass... Score and snap. They make a scoreing knife for this... Hold a straight edge where you want to cut scrape with the edge of a Hawk Bill Knife with the edge ground to a chisel shape, repeat several times till a clear scrap most of the way through . Snap over the table top edge. Band saw will work fine as well, the melting comes from friction (heat source) Putting the blade in backwards creates more friction, more friction, more heat, more heat, more melting, more melting , welding back together, etc.

As I said, band saw does pretty well, fewer teeth less friction but bigger teeth. Must keep at least 2 teeth in contact with the surface (thickness) to keep the chatter and chipping down, so don't go too course, Too fine keeps too many teeth inside the cut, and the chips are hot so they tend to melt in the kerf.

It is the quick removal of the scrap that will keep the piece cool.

Another way to help is with clear packing tape. Adhere Top & bottom to the surface to be cut, Mark on the tape where to cut, etc. Cut through the tape as you cut, the tape does several things, first it lubricates the blade and its sticky side adheres to the chips as the blade comes back and keeps them from going back in.

Another factor is speed and feed, Saw fast/feed fast Saw slow/feed slow

Another aid is Pam Cooking Spray (actually any spray lube will do, WD40 I guess) spray the blade and often as you cut to keep the chips from adhereing to the blade or the work piece.

[Jesse Cloud]

I think the idea with plastics is to carry the cut pieces away so they don't weld back together. Therefore a bandsaw with a fine blade, 7 tpi or more, would be what I would try. Hopefully the plastic would cool off by the time it got back around if it was still in the gullet of the blade, and better yet it gets knocked off and into the dc. Jim.

Hey Jim,
That's what I was hoping, too when I tried that, but I got long stringy plastic melts all over my bandsaw's innards. Took a long time to clean up and still a year later every now and then a strand will come loose from some where I missed.
Yuck!

[Sean Wright]

Hey Jim,
That's what I was hoping, too when I tried that, but I got long stringy plastic melts all over my bandsaw's innards. Took a long time to clean up and still a year later every now and then a strand will come loose from some where I missed.
Yuck!

Those things are nasty! I'm still picking the occasional plastic nugget out of my tablesaw's insides.

[ken werner]

How about buying it from the supplier cut to the size you need?

Ken

[Ed Nelson]

Bill gave the answer I would use. Score and snap!

[Jim Bergstrom]

Sean I have cut plexi and other plastics (vinyl siding, light panels etc.) with a cheap plywood blade mounted backwards on both the table saw and circular saw. Worked like a charm

[Stuart Ablett]

Here is what I do, I was shown this by a guy at a plastics shop.

Take your TS blade and tilt it at 45 degrees, then bring the blade up so just the very top corner is above the table, set your distance from the fence, and run your piece through the saw, you now have a nice "Score" on the piece, where it will snap off easily. When you are done, put the piece on the edge of the workbench etc, and snap it off, works like a charm.

If you are worried about it, or the piece is fairly thick, you can flip the piece over and run it through the saw again, this gives you a score on both sides.

Try it on a small piece first, just to see, it works, and well.

File the edge with a fine file and then, if you are brave, you can smooth the edge with a propane torch

Cheers!