Thin Lexan?

[drventure]

I've been scoping around for something to overlay my CP with. I can't really use standard 1/8" plex or lexan because, well, it's already done, so the clearances just wouldn't work.

But I've found various lexan sheets online with thicknesses down to .03

Anyone have any experience with lexan sheet that thin? Would it hold up, not be worth the bother, etc?

[RandyT]

Anyone have any experience with lexan sheet that thin? Would it hold up, not be worth the bother, etc?

Lexan is usually a bad idea for non-structural applications.  It scratches much easier than acrylic, but it is less likely to crack as it is also less brittle.  That also makes it harder to machine, because it gums up more from heat.  Another issue is that it will yellow over time, more so if exposed to UV / sunlight, etc.

A cheaper, and possibly better solution for thin and clear overlay material might be PETG (soda bottle plastic).

[DNA Dan]

Lexan is a brand name polycarbonate. It's better known for having high impact resistance. It does however scratch easily. Acrylic has better scratch resistance and is more brittle. Since you will be supporting the CP from underneath, acrylic is probably a better choice if you can cut it cleanly without chipping. Tapplastics.com has regular acrylic in 1/16" thickness. I've never cut stuff that thin, so I don't know how difficult that would be.

They also have an AR version (Abrasion resistant) with two grades, however it only comes in 1/8" minimum.

[Turnarcades]

We've always used 2mm Lexan for our cpo's and it holds up just fine. This isn't as thin as you want to go but I can say that it's excellent for working with with wood cutting tools as it is very crack resistant. In terms of scratch resistance, the only place it tends to accrue scratches over time is around the joystick dust washers, as I've also seen on the much harder to work with perspex surfaces anyway.

[drventure]

Hmm. McMaster carr has "polycarbonate" plastic film at 1/32 in 2'x4' sheets for 10$
They mention abrasion resistance but I can't tell from the site whether that particular sheet is or not

http://www.mcmaster.com/#plastic-film/=c1ube6

Based on some specs on the web, a typical CD is 1.2mm thick, which is about .04inches. So .03" thick sheet would be slightly thinner than a CD. That seems like it'd be stiff enough.

That 2mm stuff sounds like it might work. I need to take another look at my CP, but I'm betting I could bevel the edges and it wouldn't be any problem. Much more than that though and I might start having clearance issues.


I'm just wondering about the scratch resistance, as Randy mentioned.

Ah. This place

http://k-mac-plastics.com/petg-sheet.htm

does PETG sheets at .03 thickness for 45$ for a 4x8' sheet (way more than I need but they appear to only sell full sheets).


Also found this

http://acetal-rod-sheet.com/acrylic-sheet.htm


Hmmm, Might have to order a few small sheet samples.

Thanks everyone. That gives me some good things to look for...

[Turnarcades]

You can easily sand or router the edges of Lexan to bevel or smooth the edges, just FYI if you choose to go down the 2mm route.

[TopJimmyCooks]

I would try something besides .187" lexan if I build again.  there's really no way to work it except to cut oversize with a laminate trimmer bit, then template and rout it.  Extremely gummy when machined.  After breaking a couple of pieces I barely had enough to finish.

on the good side it is available from lowes and HD in various sizes if you want to check it out.