Cutting plastic on a table saw

[Meursault74]

Any time you’re trying something new w/ a power tool add a full face shield on top of your safety glasses. There are some pretty ugly faces out there that still have two good eyes.

Face protection/ Eye Protection and that picture reminded me of this song/video by NOFX called "Stickin' In My Eye"

 

[PCMusicGuy]

Another option is if you can figure out how to hold or fixture the vent you could maybe use a sharp utility knife to scribe it deeper and deeper. After enough of that, I think you could make a clean break along the line.

 

[FMB4]

Various sized door vents are super cheap. Don't waste your time trying to cut plastic on table saw.

 

[kap]

Why does reversing the blade work in my application? thx

You don't want the teeth to snag the thin plastic - it will tear it up. I have cut plastic (and thin sheet metal) with a 140 tooth plywood blade on backwards. Lower the blade so it is just a bit higher than the thickness of the plastic. Might help to hold the plastic down with a scrap piece of wood NEXT TO the saw blade.

 

[nadogail]

Blue Masking tape on the plastic will be your friend.

 

[rlitman]

Blue Masking tape on the plastic will be your friend.

It helps. One of the issues with many plastic cutting methods is that they can end up melting more than cutting, and the molten chips can stick to the base material, leaving you an ugly mess. Tape helps with this.

 

[MerlinsBeard]

If it was me, I'd probably do the following.

1. Set up a laser level on a ladder placing the vent on my bench horizontally getting it aligned so that the laser showed the amount I need to cut off. I use CD cases and spare CDs to fine tune the height of the laser line.

2. Double check by measuring the depth with a small 6" fine ruler for accuracy the length of the vent.

3. Use blue masking tape to give a clear line to cut on all four sides. If the tape width is too large, you can roll the extra around the edge on the other side. Recheck with a ruler after taping around the vent.

4. Then I'd spring clamp the edge of the vent to a piece of wood for extra stability.

5. Then I'd probably try to clamp the wood to a bench leg to keep it vertically in place.

6. Use a hacksaw and slowly nick the corner and use the tape as your guide slowly cut the appropriate width off. You may need to adjust where your spring clamps are as you go.

 

[nateo]

If it was me, I'd probably do the following.

...

If it was me I'd set my table saw depth to just clear the bottom lip, set the fence to the appropriate depth, and slowly slide the vent through on all four sides (wearing appropriate PPE and using push blocks, of course).

And if it blew up I'd probably still have time to get to the store and buy vents of an appropriate depth while you were setting up your laser!

 

[Hank11]

Various sized door vents are super cheap. Don't waste your time trying to cut plastic on table saw.

This^^^^^^^^^^^^^^^^.
Sometimes cutting plastic is fine. This is not one of them. Buy a Vent that fits.

 

[Viper98912]

Cut some plastic today with my dremel...

No issues...

 

[PugetDude]

Blue masking tape on the vent, mark the cut line on the tape. I’d use a continuous rim diamond blade from my tile saw ; no teeth to grab and shatter the plastic. It will melt it’s way through. But, I have several old blades I don’t care about, YMMV.

 

[Daniel Dudley]

I'd cut a piece of 3/4 inch wood as wide as the side of the vent. I'd secure it to the guide and I would run the blade up through the wood until it was up about 3/8" higher than the wood. I'd run the lip of the vent down the side of the wood, so the plastic you want to rip is right down tight to the wood, and I would use a fine 40 or 60+ tooth blade in the usual direction. Running the blade up through the wood gives a tight support all around the blade, so the plastic can't get sucked down by the blade. You keep it tight, and it will be less likely to give you trouble. I do it the way I have described, because I have seen what happens if you don't. Wear eye protection. That **** will hurt you if it hits you in the face.

FWIW, there are lots of ways to cut that. I have run a lot of stuff through a table saw, but I stack the odds in my favor. A little Japanese saw would cut that nicely.

 

[Daniel Dudley]

Cut some plastic today with my dremel...

No issues...

Nice suggestion.

 

[Super Mech]

I’ve cut greenhouse panels on a table saw with a 200 tooth steel blade I got at Home Depot for about 10.00. It made beautiful cuts but that plastic dust is a PIA.

 

[formula388]

Id use my oscillating multi tool. (Fein saw)

 

[BigGarage]

I need to cut a plastic door vent down to size for my laundry closet door. The door's stiles and rails are 1 3/4" thick. But the panel is only 1/2" thick. The vent is 1 1/4" thick. If I can remove some plastic off the vent, it will fit snug. Cutting along the red arrow. Can I run the vent thru the table saw without tearing it apart?

I've never tried installing the tablesaw blade backwards but when I tried to use it normally on a quad outlet cover it shattered the cover immediately. I ended up heating the blade of a utility knife until it was red-hot, then I'd make a cut as far as I could until the blade cooled off (very quick). I had a short distance to cut though, it looks like you have more. This method works but it takes a while.

Dennis

 

[rlitman]

...I ended up heating the blade of a utility knife until it was red-hot, then I'd make a cut as far as I could until the blade cooled off (very quick)...

I used to do this by using a piece of 1/8" mild steel ground to a taper held in vise grips. The thicker steel holds more heat, so you can cut further.

I've since built a hot wire cutter for such work, and it's way easier.