How to cut 1/4 inch plastic, band saw or scroll saw

[PeterM]

I'm wondering what is better to use, to cut 1/4 plastic sheet, by way of a scroll saw or a band saw. Maybe you can also advise me as to the speed. The sheet is only about 12 " long. Is there any lubrication necessary...Many thanks for the help....paranoid grandpa.....

[David Starr]

For plastic you want the slowest speed possible. At high speed the stuff melts and sticks to everything (the blade, itself, the kerf). I'd go for the bandsaw over a jigsaw unless the work needs really sharply curved cuts. Since it is only 12" long consider using a fine tooth handsaw. Leave the sticky paper on the plastic for the cut. There are various types of plastic, some harder, some softer, sold under all kinds of tradenames. You might ask the counterman at the plastic dealer which types cut more easily. I had a lot of trouble with plastic cracking around drill holes in years past.

David Starr

[Don Fearn]

I think it was "PeterM" who stated:

I dunno what kind of plastic it is compared with yours, but when I cut a motorcycle windshield down to size so the rider can just see over it, I use a sabre saw with a course blade at high speed for best results.

Using a finer blade at a low speed *seems* like it should work better, but then the kerf fills with liquifying plastic, whereas the coarser blade makes a clean kerf.

Leave the protective paper on the plastic while cutting, unless it's already off, in which case I recommend masking tape over both sides of the plastic where you're doing the cut.

You didn't ask, but after cutting, I use a belt sander with progressively finer grits of paper to smooth the edges, finishing with a ROS and even finer grits until the final sanding by hand down to the smoothness I want (usually 400-grit).

-Don

-- It was recently discovered that research causes cancer in rats

[PeterM]

Thanks Don and David, at least I feel better now.. I appreciate you David Don for taking the time to answer. I'm glad I didn't take the paper off, and maybe I try both ways to see what my results are........Grandpa in CA

[Larry]

Different kinds of plastic will behave differently. I don't own a bandsaw, but when I've used a scroll saw the biggest problem has been melting and rejoining of the cut edges. For a straight line cut I've always had best results with a tablesaw, the wide kerf & large blade simply eliminate the melting problem. This includes lexan, plexiglass, polyethylene and an unknown or 2.

[Don Fearn]

I think it was "PeterM" who stated:

Uhhh . . . actually the best way to cut sheet plastic is to score it several times with a plastic scoring tool like this:

and then snap it across the score line. Sorta like cutting glass, only you have to score it several times to get a good cut, and then snap it across the edge of a table or workbench.

I totally forgot about that 'cause you were suggesting different saws for the job; but that is the way I always cut sheet plastics . . . .

-Don (sorry for being distracted)

-- It was recently discovered that research causes cancer in rats