Best way to cut plexiglass without a laser cutter?

I need to cut a 9" diameter circle out of a 12"x12", 1/8" thick piece of clear cast acrylic (making an infinity mirror). I've cut this stuff with laser cutters before but don't currently have access to one.

I have a circular glass cutter but I'm not really clear how that does me any good - it scores a circle but the acrylic doesn't seem brittle enough to snap off nicely along a circular line. I have a jigsaw with a wood blade but that just snagged and made the acrylic shatter.

I have made rectangular cuts before by scoring a straight line with a utility knife, then lining that cut up with the edge of a table, and hitting the suspended piece of acrylic with a mallet - it snaps right off.

I'm just not sure how to make a circular cut. Finer-tooth jigsaw blade? Approximate it using the score-and-snap method for a many-sided polygon with a bunch of straight cuts?

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Use the circular glass cutter.

Replace the glass cutter blade with a sharpened steel rod that will fit the circular cutting jig.

Score the plexiglass deep and I mean very deep.

Then freeze the plexiglass in your freezer.

It should snap so clean you would swear it was cut on a lathe.

Joe
Ben Finio (author)  Josehf Murchison3 years ago
Interesting...I might have to give that one a shot just out of curiosity.
I have a pile of plexiglass that is soft and is a royal pain to cut except when I freeze it, the plexiglass cuts clean.

This works on other plastics also.

Joe
Jig saws should work fine. LUBRICATE the cut with water, to prevent binding up the saw. A woodblade is too coarse. You need a blade with AT LEAST three teeth across the thickness of the material, so here, a metal blade is probably best.
Kiteman3 years ago
I'd be inclined to cut lots of straight lines to make a jagged circle, then file and sand it smooth.