Cutting Plexiglass

[MFannin]

Looking for tips on cutting plexiglass with the scroll saw.  Or even should I try it?  I'm a newbie (as you can probably tell).  Thanks for your advice.  Mark in Colorado.

[DWSudekum]

Mark,
A lot of consideration must be given as to how thick this plexi is going to be and what speed you are going to be cutting at.  The thicker the plexi the more it will need to have the kerf cleared.  They make blades that are for this purpose and they clear the cut plastic from the kerf so that the cut does not weld itself back together as you cut it.  That said using any of the blades with the ultra reverse - that is blades with some of the teeth facing the other way - will tend to promote this self healing of the cut.  Using a blade that only cuts in one direction and does not have too many teeth and that will allow the kerf to be cleared and setting the cutting speed are all important items.  Look for blades that allow you to check off most if not all of the points listed and you should be ok.  Experimentation is recommended though.

DW

[MFannin]

Thanks for the expert advice.  I will study more about blades and be very careful. 

[Rapid Roger]

I have cut SOME plexiglass over the years and DW is correct about cleaning the kerf well or it will melt right back together.
When we use the term "weld" or "melt", that is exactly what we mean. Heat is bad when cutting anything with any kind of blade, and plastic is the worst. It will melt right behind the blade and trap it so that you can't back out and when you stop, it seizes the blade in position and you can not go forward either!
All that being said, it is obvious that you will want to use a slow speed and be slow moving forward to keep heat at a minimum. I have only cut 1/8" and with very easy curves so if you are cutting small tight patterns or thinner or thicker material, I have no more advice.
I have no suggestions as far as blades either, so go with DW on that.


Rog

[Dennis123]

I cut a bunch of 1/4" plexiglass a couple of years ago but, it was some pretty big pieces where I used a jigsaw rather than my scroll saw.  The dealer that sold the plexiglass supplied me with some special blades and they worked very nicely without any welding or  melting issues at all.

Talk to your plexiglass supplier and he might be able to suggest some scroll saw blades for you.

Dennis 

[GLC]

I typically cut with the Flying Dutchman Ultra Reverse blades for Hardwood and Baltic Birch.  They serve me well in these applications.  Last Christmas I cut a few things in Plexiglas and used these blades and experienced the overheating kerf weld up issue.  Very aggravating!  As others suggested - research for blades designed for use on Plexiglas and try those.  Regards, GLC in Cypress, Texas

[Bill Wilson]

Not all material called Plexiglas is the same.  It's sort of a generic name for acrylic sheet material.  Acrylic does tend to melt behind the cut, with the slightest of heat, so getting the right combination of blade speed, feed rate and blade is critical.  I've cut polycarbonate, which looks just like what most people would call Plexiglas and it was less prone to fusing back together.  Maybe it has a higher melt temp, dunno, but there is a definite difference.