Originally Posted by BlueBoy
A rotozip comes with a attachment for cutting circles up to around a foot
If "rotozip" is what I think it is - the newer "rotary saw" cutting tool - then I heartily agree it's a better cutter for plexiglass than using a scroll saw of jig saw or any saw with a reciprocating blade. The only problem I see with the rotary cutter is using the "jig" for circles implies making some sort of mark at the center of the piece - at the anchor point. That may not be acceptable if the circle cutout is the object of the cut. IOWs, if you were 'wasting' the center, there would be no concern for making an anchor point.
So, a workaround for the anchor point would be to use another layer of something that will not move around while the cut is being made. I'd have to work it out since I've never done this. Good idea though!