Cutting plastic

[jscott2]

Tried cutting plastic (cutting board type - polyethylene) yesterday - quite a hassle!!  I tried the largest FD is had, a #5, at low speed but the solidified behind the blade.  I found an old pinned blade, without the pins, and it worked quite well, as long as I moved the cut along quickly.  As soon as I slowed down, the kerf closed in. 

The blade is used has about 18 teeth per inch but is quite thick and 1/8" wide.  The size doesn't help much at making sharp turns but I think the extra width made a wider kerf that didn't close in.  I know Mike recommends Polar blades for plastic but I wanted to cut now.     

What has your experience been with cutting plastic?  Any suggestions would be appreciated - blade type, speed, etc.

Thanks and have a good day,
Jim

[Dan26]

Hi Jim. When the blade gets hot it transfers heat to the plastic causing it to melt. If you move the blade faster the plastic doesn't melt as much and you may be able to get a better cut. But, moving the blade faster doesn't always make the best cut. Try putting clear box tape over the pattern. It allows you to see the pattern and the make up of the tape also seems to lubricate the blade allowing it to run cooler. It works great for Plexiglass but I've never used it on a cutting board. If the tape works, you should be able to use a smaller blade and slow down your cut.

Let us know if this works for you.

[jscott2]

Dan, forgot to mention that I used blue painter's tape, then the pattern, then clear packing tape all around the blank. 

Thanks,
Jim

[Rapid Roger]

Slowing the speed of the blade down helps some also. The faster speed causes heat in the material no matter what the material is. Even wood will burn somewhat (especially cherry) and the thicker it is the more heat will be generated.

Rog

[Kepy]

I have found that putting masking tape on the cut lines, it doesn't melt back.  Worked great on 1/4" plexiglas.