# Cutting Thin Plexiglass (Plastic)



## clieb91 (Aug 17, 2007)

Hey All, Looking for some suggestions on cutting some thin plexiglass. I am looking to do a few projects for kids that require a plexiglass shield and want to make sure I get the cuts nice and evn and I guess sand the edges so they are not sharp. Any one that has worked on something like this and could give me a few hints I would appreciate.

CtL


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## Keen1 (Nov 14, 2007)

Can you use lexan? I recently cut an 8X10 piece with my miter saw (and a fine tooth blade) to protect a picture going on a plaque. Very easy and sanded the edges. I've never tried plexiglass for such a purpose because the lexan is so easy.

If you can't use lexan, (and assuming you don't have a wet-saw at your disposal), I'd say bandsaw would be next best bet or a grinder.

No matter which method you use, tape over your cut lines to help reduce chip out.


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## Gene01 (Jan 5, 2009)

A glass guy turned me on to a plexiglass/lexan scoring tool, similar to one used on glass. Instead of a roller it has a fixed "V" shaped blade. If it's 1/4" or less, I just score and snap. 
Only for straight line cuts though. For curves, I use the BS or scroll saw. With either, I leave the paper on it as that reduces the melting and rejoining behind the blade.


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## hairy (Sep 23, 2008)

http://www.ehow.com/how_2056832_cut-plexiglass.html

Once it's cut, take a plumber's torch and warm the edges. It will glaze them over and smooth them. Practice on the waste cutoffs.


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## Kindlingmaker (Sep 29, 2008)

I cut striaght cuts on the table saw using a blade made for plexi and composits, works great.


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## scrollgirl (May 28, 2010)

You can easily cut it on a scroll saw. You just need to slow down the speed a bit so the heat doesn't build up from the blade and melt it back together. You get ultimate control and it is safe to do. Just a touch up sanding on the edge and it is good to go. 

Sheila


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## Abbott (May 10, 2009)

I regularly cut Plexiglas on my table saw, it works very well. I usually always just use the blade that happens to be on the saw at the time and go slowly. But a 60 tooth blade will cut it perfectly. I have never tried a TS blade that was made to cut Plexiglas as was mentioned above but I would imagine it would work very well…I have just never needed one.


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## clieb91 (Aug 17, 2007)

Thanks All. 
Hairy, Thanks for the link.
Sheila, I have yet to add a scroll saw to my arsenal.. errrr workshop.  though it is on my list.

CtL


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## Claymation (Sep 9, 2010)

http://www.forrestblades.com/nomelt.htm


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## Finn (May 26, 2010)

I have had bad luck cutting 1/8" plexiglass on my scroll saw but the bandsaw cuts it very well.


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## surfin2 (Oct 24, 2009)

The cleanist cut I found was with a router…


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## superdav721 (Aug 16, 2010)

has anyone tried to turn there blades around backwards. I have cut pvc and vinyl this way.


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## surfin2 (Oct 24, 2009)

Why would you cut pvc with the blade backwards, I've done it the normal way & it work'd just fine…
I've tried vinyl both ways & got the same results… I was told that it was a difference in chip out but I think its between Sharp & dullness… Save yourself some time use a sharp blade & cut it the regular way…


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## JimDaddyO (Dec 20, 2009)

I use a straightedge and score a line a bunch of times with a sharp utility knife. Then I clamp a board at the score line, with the score line on the edge of a table. Then I snap it. Sometimes a bit of sanding to clean it up.


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## Jonnyfurniture (Aug 29, 2010)

They make tripple chip blades for cutting plastics. I cut it all the time with a standard blade though. I raise the blade up a little to have some extra down cut action. I never understood how the backwards blade thing is supposed to work. I guess the sharp edge of the carbide scrapes away material. Seems a silly thing to do and plexi would take a long time to cut.


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## peteg (Sep 2, 2010)

As the others say, a regular tungsten blade will cut good, dont rush the cut, the main thing is to have your blade set right down so when it cuts you're only showing about 1/4" max blade above the cut this will reduce chiping


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## newbiewoodworker (Aug 29, 2010)

I used my bandsaw to do it. With a 14 tpi blade. Easy as pie. Just be sure to use tape on your cut-line. It will prevent chipping(tape both sides).

You can also use a square and a utility knife… but anything over 1/8 inch is a pain in the a*se to do.. if its 1/8, just be sure to use a window sill to snap.. nice and easy..


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## Pimzedd (Jan 22, 2007)

Maybe I can help. I taught Plastics Mfg. for 34 years. Lots of plexiglas fabrication.

First are you sure you are using plexiglas? Plexiglas is an acrylic plastic. Some clear plastic sold in stores is styrene. Acrylic is harder and does not scratch as easy. Styrene melts very easily when sawed.

Next, define thin. 1/8 in.? 1/16in.? Less?

For 1/8 in. and up, use a table saw blade with as many teeth as possible. A thin rim plywood blade from the local big box store will work until it starts to get dull. That can happen pretty fast as plexiglas is fairly abrasive.

The best blade is the Forrest No-melt that Hairy recommended. A 10 in. cost over $200 but they REALLY WORK.

If you don't have many cuts to make, the scoring tool that Gene Howe wrote about works well. Follow the directions on the package to get a straight edge. You will need to smooth the edge after. A jointer will work well for that. A scraper made from the back of a hack saw blade filed flat across the back of the blade, not like a knife, will work as well. The scoring tool is cheap, less that $10. They can be purchased from most sheet plastic suppliers and online. A utility knife will work but not as well.

Now for material less than 1/16 in., you can really get into cracking and chipping problems. Peteg's suggestion of getting the blade where it is only about 1/4 in. above the material is real important. If the blade is too high, it tends to drive down and chip the plastic. You will need to play with the feed speed to get the best cut. If the materials is masked with poly film, it may still chip. Remove the film and use masking tape, the stickier the better, where the cut will be made. Put strips of painters tape completely across every 6 in. or so to prevent scratching.

One final note (here is the teacher coning out). The name is Plexiglas with one "s". Plexiglas is a trade name for sheet acrylic originally manufactured by Rohm and Hass. There are lots of trades names for acrylic sheet and plexiglas has become the accepted generic name for them. If you can find and afford real plexiglas, it is better for sawing and cutting than lots of the material out there. Plex G is very good. Plex MC is ok.


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## kimbcarling (Feb 27, 2012)

hello
i work in tool rental at Home Depot, I have some ladies comming back tonight to once again try and cut their 1/4 inch plexiglass (i think it is plexiglass) we tried a coping saw,tile cutting saw, exacto blade,and a band saw. I am not sure why this material keeps shattering, even tape dosent help.


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## Dal300 (Aug 4, 2011)

Plexi is pretty brittle and unforgiving.
What usually happens is that it isn't held down tight to the work surface and any blade trying to use and up/down motion causes fractures that multiply the more you saw. It doesn't take much, because each fracture will extend and widen with each iteration of a cut.
I use a router mostly, with a 1/8" or 1/4" cutter. If that isn't possible, and I have to use a toothed blade I sandwich the plexi between two sheets of Lauan or masonite to keep it form moving with the cut.

Then there is the cleanest, easiest way I've found….... heat a thick bladed cheap paring knife with a propane torch. Make a quick score along a straight edge. Do this again and again until the knife cuts cleanly through.
After you have it cut you can clean off the slag with a thumbnail or a sharp blade or some sand paper.

Good Luck.

PS: You don't work in College Station, TX do you?

DF


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## NiteWalker (May 7, 2011)

I cut plexi all the time for the small boxes I sell.
I use my table saw with typical 40 tooth gen purp blade.

Definitely keep the plexi tight to the surface of the saw or it will want to flap and make a lot of noise.
I also use an auxiliary fence tight to the surface of the saw because 1/8" and thinner can and will slip under the fence causing a kickback situation.

A ZCI on the saw is a necessity for no chipped edges.

Try to get cast acrylic if you're cutting acrylic, otherwise polycarbonate (Lexan, Tuffak, Makrolon) works just as good, though you can't flame polish the edges as it's much more finicky than acrylic in that regard. It's normally said that acrylic is more scratch resistant than polycarbonate, but IME the difference is negligible. Something that will scratch one will definitely scratch the other.

The router does work great for trimming/cutting too.


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