How work with polycarbonate plastic

[Jim C Bradley]

I have been given a 4 x 7 foot sheet of polycarbonate. It is 0.21 inches thick. What tools do you use to cut and shape it?
I guess it's Twenty Questions---does anyone have practical uses for this material (router bases, zero clearance inserts, other)?
Enjoy,
Jim

[Eric Wong]

I've worked with 1/4" Lexan, is that the same? I can't remember what types of plastic are what, polycarb, PET, UHMH.....

Anyway, I used my tablesaw to cut it. I've also used the bandsaw, just be careful not to cut too fast or the plastic can melt a little bit. Creates a mess. And cutting plastic smells bad, but I don't think the fumes are dangerous unless you melt it.

I've used it for clear router bases, case fronts where glass would be too risky (like in children's furniture), and for a couple jig parts like safety shields.

[mark page]

I like Eric--too many types to keep track of. If same as mine, I use for router jigs and templates. Bandsaw on the outside diameters and scroll or jigsaw for inside diameters. Makes great templates for use with router guides or bearings. I use especially for oval keyhole steel inserts for hanging items, quilt racks, coat racks, large picture frames, etc.

[Alex Berkovsky]

Jim,
I am going to direct you to another web site that has a few links that may be of interest. At the top of the page you will find a section title "Acrylic Projects and Information" (http://www.reefcentral.com/diy/?menu=12)

Here's another one:
http://reefkeeping.com/issues/2002-04/jg/index.php

[thomas prevost]

Lexan is Duponts trade name for polycarb.

[David Epperson]

Yes. Lexan is a polycarbonate product. I love the stuff. It does not crack or craze near as bad as Plexiglas, which is an acrylic. In fact it's dang near bullet proof. A 22 rifle will shoot through a sheet that thin. but not far afterwards and the plastic will not break, just left a small hole melted through. Also in the thinner sheets it can be bent just like sheet metal without heating, I've done it with 1/8" sheets to 90° without it breaking using a sheet metal bending brake. Fairly wear resistant, but it will soften and expand if subjected to much heat. It may work as a close clearance insert, but blade contact may cause some temporary burrs. I'd have no problem using it as a router base though since it usually does not crack apart when the countersunk screws are tightened down.

[Jeff Booth]

We used to use a lot of polycarbonate at my job, the stuff we bought is glass filled and it really dulls the tools. I myself do not work it, but am aware of some of the knowledge the shop guys have acquired. We machined it using a regular CNC mill with HSS mills. We bought it in large sheets and to get it to size we used the bandsaw as opposed to the tablesaw, we do this with all plastics because I think there is a fire risk on the tablesaw due to dust/melt buildup under the throat plate at the back of the blade (but our sheets are also 2" thick). I also know that the stuff we have used is pretty brittle and has warpage issues, we started moving away from it towards more expensive gf nylon a few years ago. Having said all that I think clear lexan at 0.21" would be nice stuff as you said for router bases or other non structurally intensive tasks in jigs etc. I will bet it stays flat. I would machine it at medium speed at first with small bites and slow feedrate on the router - look at the bit after a 10 seconds of cutting to see if there is buildup. I also know you can drill and tap it but the holding power is only so-so.

Good luck

[Jim C Bradley]

Hi,
Thanks for the info. I have used polycarbonate in the past, however only in small optical objects. I didn't know Lexan was poly.
Enjoy,
Jim

[Jim C Bradley]

Hi,
Outside curves may be OK. However, inside curvers may be a different matter. The jig saw I inhereted is an old Sears...back when the cord was two wires. It also has a metal body. I think it is as old as I am---and that is OLD.
Thanks for the ideas and Enjoy,
Jim

[Jim C Bradley]

Hi Alex,
I am going to have to clone myself so one of us can study plastics full time. Thanks for the info.
Enjoy,
Jim

[Jim C Bradley]

Thanks Thomas.
I am glad to learn that Lexan is DuPont's polycarbonate trade name. I had seen the word Lexan before but thought it was an entirely different product.
Enjoy,
Jim

[Jim C Bradley]

David,
Thanks for the information. I guess (hope) I will have some fun seeing what I can do with the poly.
Enjoy,
Jim

[Jim C Bradley]

Hi Jeff,
From what I have heard, I am sure glad I am not paying for two inch thick polycarb. I have picked up some interesting ideas from members. I had not thought beyond router bases and zero inserts.
Some members mentioned heat and hard on tools. At least in the begining I will try it with cheaper blades.
Thanks for the input.
Enjoy,
Jim

[Dave Anderson NH]

Misinformation folks. Lexan is the General Electric trademark for polycarbonate sheet. DuPont makes Lucite acrylic but does not produce any polycarbonate. Impact resistance is polycarbonates strong suit. It is actually softer, slightly more flexible, and easier to scratch than acrylic. It also has a higher heat distortion temperature by about 80-100F.

Addy Protocol: I have designed, sold, and worked with plastic for 30 years for a variety of companies in the industry.