cutting plastic on table saw?

[Robert Meyer]

I have purchased a few sheets of plastic (acrylic?) at the Borg and need to cut them. They are 30x36" and are 3/32' thick. Can I cut them on my table saw using my WWII blade? I realize I will need to prevent the plastic from possibly sliding under the fence. I tried to cut one with a utility knife and after scoring it a bunch it cracked.

[rob mason]

I have cut acrylic on my TS with both disastrous and successful results. Disastrous in that I underestimated how much the blade made the acrylic 'chatter'. I ended up ruining one piece. On the next try, I used a push block providing downward pressure as close as I could to the blade and it worked fine.

[Art Moore]

The .090 acrylic will slide under the fence, and will have a tendency to ride up the blade and chip if you try to cut it unsupported (I found out the hard way). The best way I've found to cut it is to place a piece of 1/4 MDF under it, and cut both pieces together while applying downward pressure on the acrylic. Of course, a crosscut sled might just work too...

[Kevin Groenke]

Most blade manufacturers make blades specifically for cutting plastics. A blade with a triple-chip grind and a negative rake angle will work best. The same blade can be used to cut non-ferrous metals and are often labeled as such.

The WWII has an alternating top bevel (ATB) grind and a positive rake angle. This blade will probably tend to chip the acrylic and the acrylic may be tough enough to break off the very tip of some of the ATB teeth (though this might be on a microscopic scale.

Here are some inexpensive blades that would do a great job on acrylic sheet. This is not an endorsement of Amazon, just an easy place to search.

http://www.amazon.com/Freud-TK706-10-Inch-Non-Ferrous-Cutting/dp/B00006407O/ref=sr_1_1?ie=UTF8&s=hi&qid=1221348797&sr=1-1

http://www.amazon.com/Hitachi-974642N-10-Inch-Non-Ferrous-Plastic/dp/B0006HKBY2/ref=sr_1_11?ie=UTF8&s=hi&qid=1221348797&sr=1-11

[Tom Veatch]

Robert, if it was me doing it, I'd follow the lead of the other posts and use a supporting piece under the acrylic - sort of a sacrificial ZCI. I'd go one step further and use a piece above the acrylic as well. Sort of sandwich the acrylic between two sacrificial pieces. I'd set the blade height to not cut completely through the top piece and use a featherboard or other hold-down device to prevent the sandwich from riding up on the blade.

Good luck.

[scott spencer]

Robert - I've cut the plexiglass stuff from the BORG successfully on my TS but for the life of me I can't remember which blade I used. :rolleyes: I think you'd do better with something like an 80T blade with a lower hook angle than the WWII but the WWII will probably do fine. Try a test cut to be on the safe side.

[Steve knight]

that plastic is pretty crappy and likes to melt.

[Gary Herrmann]

I've cut UHMW using my WWII. No problems.

[Ed Gerken]

I've used my scrollsaw, but it tends to re-fuse behind the blade. Still, it's weaker along the cutline if I cut quickly and I can usually get a fairly clean separation. Then I remove the bigger globs of fused plastic and belt sand to a smooth edge. Obviously I'm starting with relatively short lengths and just going for a smaller piece and not making display cases here.

I've used the wood sandwich method before to cut thin metal without dimpling up the edge and that worked well.

-Ed

[David G Baker]

Didn't read all of the posts but I have had some bad plastic vs table saw experiences. I switched to the blade that scores the plastic that the Borgs sell specifically designed for that purpose. It has worked well for me. If the plastic was thick I would use a table saw and a blade designed for cutting plastics.
At one time I bought a lot of Plexiglas from Tap Plastics. Tap had a cutting room and a carbide blade on a table saw designed to cut the product. The cuts were always perfect.

[Philip Giangarra]

This summer I successfully cut 9 of the wavey plexiglass panels (the kind you use for roofs) using a plywood blade flipped backwards. It worked great, and I had a very smooth edge.

[Kevin Groenke]

I've cut UHMW using my WWII. No problems.

UHMW is much softer and less brittle than acrylic and be cut with pretty much any blade.

We've cut miles of acrylic as thin as .050 with a 80T triple chip blade with a negative rake angle.

Saw Blade Grind:
http://www.ez2love.com/images/sawblade.gif
The Triple chip grind is used exclusively in combination with other profiles, usually the flat top grind, to mimic the scoring action of a two blade scoring saw. The top of the triple chip is slightly higher than the other teeth allowing it to precut brittle materials prone to chipping.
The Flat top grind is primarily a rip cut profile, although it is used on thin kerf blades for general purpose cutting, and economy blades because it is easier to sharpen.
The Alternate bevel top is a general purpose grind used primarily for crosscutting hardwoods and softwoods. Its sharp corners score the wood, resulting in a clean cut.
Regards, Darryl Yeager (EASY TO LOVE TOYS)

[Craig T. Smith]

I have cut plastic on my TS, with mixed results. I have better luck with a circular saw, saw guide and plywood blade on forewards. Anyway you do it cut slowly. Craig

[Jim Becker]

I don't know if it was already stated, but this is one of those cutting situations where you absolutely want to use a zero clearance insert to insure that the material is well supported completely to the cut line.

I've cut the material many times with just my WW-II blades, but if I were going to do it on a regular basis, a blade with the correct tooth geometry will make for better results with less edge cleanup required.