finishing plexiglass/acrrylic templates?

[Simon Magennis]

I got some plexiglass sheets for the first time and am trying to do some accurate templates. On my fist attempt I cut out the shape with a hand fretsaw. It is reasonably accurate but the edges are not perfectly even. I sanded them a bit and also tried to use a file to get the edges more even. I am not completely happy with the results - useable but not pretty. (I don't have a bandsaw.)

How do you make templates and fine tune them? (Saw type? Sandpaper? Files?)

[Alan Carruth]

I find a small drum sander in the drill press works well. Once I have a drawing I like I lay the plexi down on it, and scribe the line onto the plastic. Saw close to the line, and then sand down to it with the drum sander on a slow speed.

[Chuck Tweedy]

Simon, there are special router bits and saw blades for plastic.
The geometry of the cutting edge has to be different to keep from melting and digging in.
THESE for example. Look in the list for the "For Plastic" bits - my URL didn't take us to the final page

[Barry Daniels]

I have heard of flame finishing the edge of plastic but I have never tried it. It supposedly slightly melts the edge and it hardens to a more glass like surface.

[Chuck Tweedy]

Yes, you can both vapor polish and flame polish plastics like acrylic and PC.
However both require quite a bit of process development to get it right for your part. These operations are usually reserved for manufactured parts that are made in high quantity.

[David King]

Getting fair curves is what solid body guitar building is all about. Your best tools are your fingers which can feel deviations of .001". I recommend a stick-on sandpaper in the 80-120 grit range stuck onto thin, flexible sections of wood, metal, plastic or whatever else you have at hand. You want the backing material to be just flexible enough to bend to the desired curves but too stiff to get into all the bumps and lumps. The desired result is that you quickly sand the tops off all the lumps and bumps and end up with a nice smooth "fair" curve. Your fingers will tell you when you've achieved that.

[Alain Lambert]

A scraper will work fine to smooth the edges.

[Todd Stock]

We use Lexan (polycarbonate) in lieu of Plexiglass/acrylic - less likely to scratch/chip/shatter in use, and much easier to work with the tools found in most hole shops. Cost is 2-3 times acrylic sheet, but polycarbonate sands cleanly with no melted buildup at the edge, can be jointed and planed with hand tools or jointer, and can be drilled and threaded with standard metal and woodworking tools (although modified drill bit are more controllable). Most importantly, it will not crack or shatter.

Home Depot/Lowes carries .100" and .220" thicknesses, which work for body and neck templates, and we use 3/8" and 1/2" off-cuts from Piedmont Plastics for router templates...the last off-cut we purchased was a 1/2" x 36" x 22" for about $30. Lean scrapes and files cleanly, and we buff the edge on our StewMac buffer without issue.