Cutting very thin plexiglass

[Muse]

I have a rectangular clear piece of plexiglass, ~20" x 15" x 3/64"

It's very thin, rather flexible, has a peel-off coating on one side. I'd like to cut off 2-3 inches from one side to make it around 15 x 17"

I have no replacement so I'd like this to work out and cut in a straight line. How can I do this? I have a jigsaw with a fine blade, but I'm afraid it would shatter.

I could score on one side deeply with a box cutter and try bending it over that cut, or try to score deeply from both sides, maybe the better idea, although I'd have to be careful to get the cuts right on top of each other.

What's the right way to do this?

 

[Muse]

I did a search and one site had this:

Use a handheld rotary tool with a cut-off wheel for very thin Plexiglas where the material is too flexible for scoring or sawing. Secure the Plexiglas firmly with clamps on a solid working surface, but remember to leave a gap under the area to be cut. To make a clean cut, ensure that the cutting tool is operating between 10,000 and 15,000 rpm. This will give a straighter, cleaner cut. Follow the marked line while maintaining a standing position that allows you to see exactly where to cut. Once finished, smooth the edges carefully with a fine-grit sanding accessory on the rotary tool.

I may try something like that although I think my cutting wheels for my dremel aren't sufficient diameter to get a vertical cut. Still, that's better than a disaster where it doesn't cut/break where I want. I can dress the edge later somehow.

http://homeguides.sfgate.com/cutting-thin-plexiglas-99141.html

 

[Greenman]

I'd score and snap it, or use a router if it had to be a perfect cut. Bear in mind I know squat about sheet plastic, so it's also likely I'd end up with several pieces of it being removed by a surgeon.

 

[Muse]

Having had less than good luck scoring and snapping glass I think I'll refrain from that tactic. I have a pretty large diameter cutoff disk for my dremel that will allow me to make a vertical cut. I think I'll place a long strip of masking tape on the piece, mark that with a thin sharpie and cut on that line meticulously. The cut will be maximum 20" long, so not a big problem. Then I can dress the edge with a fine file.

 

[edro]

I don't think scoring and snapping works well with plexiglass because it is so tough.
The cut doesn't propagate through the material very well like other more brittle plastics or glass.
You would need to score it all the way through, which should only take 5 or so deep scores.
Use a straight edge and a fresh blade and it should be easy.

 

[Muse]

I don't think scoring and snapping works well with plexiglass because it is so tough.
The cut doesn't propagate through the material very well like other more brittle plastics or glass.
You would need to score it all the way through, which should only take 5 or so deep scores.
Use a straight edge and a fresh blade and it should be easy.

Should I do this from both sides? Actually try to get the pieces separated with cut-passes alone? Or get to where it's almost cut through and bend-break?

 

[gururu2]

I used to cut it with a jigsaw with no problems. I think the blade melts the plastic more than cuts it. Definitely would practice on the edge to be cut if its that thin.

 

[edro]

Should I do this from both sides? Actually try to get the pieces separated with cut-passes alone? Or get to where it's almost cut through and bend-break?

No, keep cutting into the same cut.
Go slow on passes 2-3 so you stay in the original groove.

 

[Muse]

No, keep cutting into the same cut.
Go slow on passes 2-3 so you stay in the original groove.

I figure I'll have a go at this today, not sure what I'll do. This sheet is approximately 1mm thin! D: Thick enough where getting even 1/2 way through it with a box cutter seems tough. I think I may try that and then flip it over and go at it with the dremel + cutoff wheel... carefully.

I know a guy from Columbus, OH. Very interesting guy. I've met a lot of great people from Ohio, more than any other state. I'm right now reading The Wright Brothers, they grew up mostly in OH, their family settled into Dayton when the elder brother (Wilbur) was in his late teens. Of course, the Wright brothers were huge DIY guys.

 

[right_to_know]

Totally weird, I posted the car in the vid on another thread.
The guy manages to crack the plexiglass by cutting it with a jigsaw then uses a sandpaper flap wheel to grind down the edge on a replacement piece. However it's from a TV program so you don't know if they dramatised it slightly. See what you think.

https://youtu.be/UgIW2ySVatk?t=32m9s