I think 1/4" acrylic would work awesome for strut plates. I know using it as plannels on my 3d printers made them SUPER strong and square. If you use Acrylic, and have any plans to cut aluminum with your machine, be careful using IPA, it will crack it for sure… I found that out the hard way 
If you go with Polycarbonate you will be safe there. Also if you do it and decide to etch anything into it, mirror it and etch the back side. That way you don’t fill your etched areas with dust so much
This is the plan!
Hi Bob!
How did the acrylic struts work out for you?
I’m about to tear down my LR3 For an LR4 upgrade and thought about using 1/4 smoked blue acrylic for the struts. Cost for enough for 4 struts was the same as a sheet of mdf, and I have an 80w co2 laser to do the cutting and engraving.
would love to see pics of yours if you did this.
Thanks!
I am sorry to report I ended up cutting mine out of MDF. The acrylic option is still on the table for me just haven’t had the time to get it done.
I am very interested to see how yours comes out. The eventual plan is engrave the acrylic with an edge light strip, I think the visual would be amazing and for darned sure a fun project!
Bob