Page 1 of 1

Routing Polycarbonate (Lexan)

Posted: Fri Feb 19, 2016 8:49 pm
by Bob Gleason
Not sure where to put this question, but I figured tool users would see it here. I use a lot of cast plexi to make templates for outside cuts, where I can shape the template on the bandsaw and sand to size.Currently I'm trying to upgrade some of my inside cut templates. Inside meaning templates used for routing pockets like in electric guitars or for cutting preamp cutouts in acoustics, or cutting soundports etc. These require a router or mill. Plexiglas is too prone to shattering as far as I can tell, and I hear polycarbonate is better. Brand name Lexan among others. I'm interested in hearing about routing procedures, bit speed, bits, feed speed, lubricant, and tooling that anyone has used for making inside cut templates in 1/4" Lexan. Also, can I glue 1/4" Lexan sheets together to make thick templates, and still retain the clarity? Thanks, Bob

Re: Routing Polycarbonate (Lexan)

Posted: Fri Feb 19, 2016 11:55 pm
by MaineGeezer
You'll probably want a fairly slow rpm. If too fast, the plastic heats up, melts, and makes a horrible mess.

I doubt you'll be able to laminate it and have the joint "disappear." A narrow joint, maybe. Get good tight mating surfaces and wick in some methylene chloride (I think that will dissolve polycarbonate; need to check) or possibly some water-thin CA glue. But two large flat surfaces...I dunno. You'd want the same approach, I expect -- minimal clearance and wick in a solvent or CA -- but I think it would be difficult t0 get it uniform. Why not just buy thicker polycarbonate?

Re: Routing Polycarbonate (Lexan)

Posted: Sat Feb 20, 2016 8:14 am
by tippie53
may I add that using a cooling agent helps for a cleaner cut and keeping the tool from getting blocked. I used to use dawn soap in water
about 1 spoon per qt was all it needed.

Re: Routing Polycarbonate (Lexan)

Posted: Sat Feb 20, 2016 1:41 pm
by Bob Gleason
MG-Thanks for the tips. I can get polycarbonate cut offs at the plastic supplier at a reasonable price. 1/4" is the thickest they carry and bringing in thicker material is very pricey. Hence, I want to try the glue up idea.

Re: Routing Polycarbonate (Lexan)

Posted: Sat Feb 20, 2016 5:20 pm
by MaineGeezer
Oh yes! The thick stuff gets expensive pretty fast.

Although it might come out kind of ugly, you ought to be able to laminate sheets. The trick will be to get uniform solvent coverage, and if methylene choride is in fact the preferred solvent, it evaporates almost instantly, making it even more difficult to control. It also has an incredibly low viscosity so it goes everywhere.

What do you need the thicker stock for? You could always lay down some doublei-sided tape and stick sheets together that way.

I just found this: http://www.eplastics.com/lexan-polycarbonate-glue
which may be helpful.