Cutting Acrylic and UHMW Plastic

[Keith Heyer]

Hello All,

Can somebody tell me what kind of blade to use when cutting UHMW plastic and sheets of acrylic? I will probably be using the bandsaw so I can make some runners for a crosscut sled.

Thanks,

Keith

[Jerome Hanby]

Haven't cut acrylic (unless that's what plexiglass is, I used a jig saw for that and it didn't cut very cleanly), but I just cut UHMW with my normal blade in the miter saw. It's definitely a Freud blade, thinking 80 teeth. It made nice clean cuts and produced a ton of little white "shavings". If I had stock to rip or too wide for the miter saw, I'd probably use my cross-cut blade on the table saw. If I had to make curved cuts, I'd probably take a guess and use my highest tooth count blade on the band saw.

[Lee Schierer]

UHMW machines pretty much like wood. Use regular blades and speeds. When cutting thick material I would use a rip blade because the shavings won't break up like normal sawdust. You can even run it across a jointer if you like.

Acrylic (not to be confused with Lexan or polycarbonate) is a brittle plastic and will shatter or crack if given the chance. It also melts when you cut it with high speed blades or drill bits. You'll want to use slower speeds and make sure the work is completely supported so it can't deflect or vibrate. I would not recommend running it across a jointer. Small tooth size will lessen the chance of shattering but will increase the chance of melting. Thinner stock (1/8") is best cut by scoring deeply and snapping it like glass.

[Andrew Kertesz]

I used to work in an acrylic fabrication shop. We used a standard kerf 60 tooth TCG for all the acrylic cuts, and yes you can run it on the jointer if there is enough thickness. The problem when you run it on the jointer is it leaves a razor sharp edge that needs to be relieved or polished which requires oxygen/hydrogen mix in a cutting/brazing torch. Depending on the application you can always use a razor blade to scrape the corners so they aren't as sharp.

Make your cuts with the protective film left on, same for the jointer if that is what you intend. Helps prevent scratching the face of the material.

[Bruce Wrenn]

Here we have a farm supply store that stocks a 1" X 3/8" X 120" pieces of UHMW. To make runners, I rip ever so slightly over width, and then run thru planer using a dedicated sled that grips the strip tightly, so sled and strip pass thru planner as a unit