Cutting Perspex???

[goldeneyedmonkey]

Hello all,

I need to cut some perspex down to size, will a normal fine-wood jigsaw blade be ok for this? If not what can I use to cut it? Is perspex generally brittle or not? I don't want it to shatter because I have no test pieces.

Thanks in advance, _Dan

 

[oddsocks]

Dan, I used a jigsaw once and it did splinter around the cut - but maybe with a specialist blade, no pendulum and splinter guard it will be better. The last time I used a fine bandsaw blade and a backing piece of thin MDF.

Dave

 

[Paul Chapman]

I've used a router with a 1/4" cutter on a slow speed. Used it to cut out this dovetail marker with no chipping out. The perspex was supported on a piece of MDF

You can also plane it with a finely set block plane.

Cheers :wink:

Paul

 

[Oryxdesign]

New perspex cuts easily with a circular saw but when it is old the plasticisers leach out and it gets brittle.

Simon

 

[ondablade]

My experience is more in a commercial plastics fabrication environment. Perspex/cast acrylic is generally machined using tooling very similar to woodworking - routers, table saws and the like.

But as above it often has quite a lot of stress locked into it (especially if its been bent or otherwise heat formed) - and will stress crack or craze fairly easily.

The extruded or continuous cast cheaper version especially so, cell cast is tougher.

Moderate feeds and relatively fine teeth (on e.g. table saw blades) are advisable. A fine tooth jigsaw blade though could be overdoing it - it could clog, heat up and cause melting. As OS any pendulum action sounds risky.

Bosch do a wide range of purpose made jigsaw blades for different materials - there's usually a display at a decent hardware. They do a specific one for acrylics: http://www.axminster.co.uk/bosch-bosch- ... rod724845/

Maybe dig up another piece to test on, even if it's not from the same source...

 

[Lons]

Hello all,

I need to cut some perspex down to size, will a normal fine-wood jigsaw blade be ok for this? If not what can I use to cut it? Is perspex generally brittle or not? I don't want it to shatter because I have no test pieces.

Thanks in advance, _Dan

Dan

You can cut it with fine tooth handsaw, tablesaw (pref fine tooth, neg rake blade), scrollsaw or jigsaw (fine wood blade / slow speed). If you cut too fast a speed with a jigsaw, it will melt behind the blade and make a horrible mess.

Why don't you look up signmakers in yellow pages and ask if they can give you some offcuts to practice on - they throw loads away.
If you lived closer to me I could offer you some.

If you want hints on fabricating acrylic techniques, look on the websites of ICI (perspex) and Rhom (Plexiglas) - should be still available.

regards

Bob

 

[goldeneyedmonkey]

Thanks all, very useful...

I was aware that any fast feed rate into a jigsaw would cause the perspex to heat, and I'll also try doing it at a very slow speed as far as the actual speed of the blade goes. I wanted to do it first thing this morning, and I can't get out of the 'shop because I'm waiting for DHL to pick something up, so can't get any test pieces (might just have to wing it)

I've got a decent blade on my makita table saw, it always gives a very good cut on timbers, very accurate and clean (think it's 48-60th). But how do I tell if it's negative rake?

Cheers_Dan

 

[goldeneyedmonkey]

Actually I might try your technique Paul, but I've got no Router Table at the moment, so I'll have to take the router to the perspex and mdf and not the other way round.

 

[cutting solutions]

I've got a decent blade on my makita table saw, it always gives a very good cut on timbers, very accurate and clean (think it's 48-60th). But how do I tell if it's negative rake?

Cheers_Dan

The face of the teeth lean backwards on negative hook.
But you may just get away with positive hook....again try some test cuts