Cutting and drilling acrylic plastic

[Quetzalsailor]

Drilling acrylic plastics requires special drill bits, cooling, and the correct feed speed. Go on line and buy the bits sold for the purpose; they're not as 'aggresive' as wood or steel bits. Cooling is easy, use soapy water sprayed from a chemical lab wash bottle.

Sawing acrylic plastic can be done with ordinary wood blades but you must cool and lubricate with the soapy water.

Routers and router bits work fine, but with the soapy water lubricant and coolant.

Sanders and grinders are problematical: work with slow feed speeds.

Hand files and saws work fine.

Sooner than later, you should be worrying about all that soapy water around your electric tools. Figure out how to deal with it. At the very-very least, plug into a GFI!

If you are working with plastics with good finishes, protect the surfaces with the films that they came with or add tape to slide the tools along.

Think through fasteners and cut shapes: Holes are stress concentrators. Sharp edges or rough holes are. Sharp inside corners are as well. The wedging effect of otherwise attractive flat head fasteners is bad. Too-tight fasteners are bad.

Think through clearances: Plastics have greater coefficients of expansion than the surrounding fiberglass. Leave enough space.

Use the correct sealants and solvents; talk with the manufacturers.

[Hirilondë]

I can't imagine using any coolant with a router. They are so fast it will be gone before it can do anything. Never mind that it will get all over the router and ruin it. I don't use any coolant cutting acrylic, I do when drilling.

[Zach]

Yeargh.

You mean I just typed all that in the other thread and Quetzel beat me to the punch.

(Makes mental note to read... and not post when its early in the morning...)

Zach

[Quetzalsailor]

You're quite right Hirilonde. Soapy water goes everywhere with power tools. However, some are worse than others.

The worst is with a bandsaw: water all over the inside on the guide wheels and all; but without it, it will heat the plastic in short order. Makes my Craftsman cheepie the wrong tool since the switch might well be inside and excessive water will soon find its way onto the motor. My antique ('50s) bandsaw would be better since the switch and motor are remote.

Saber saws are a quick grab but the water goes everywhere, including your face, just like chips do. A bad choice, too. A variable speed saber saw might be run slowly enough to work.

A router is actually not all that bad; the water is thrown sideways away from the tool, the motor, and you. That's presuming that the work is flat and the router is on top. I did mortices and dadoes for a long-forgotten project.

Radial saws (hand held and maybe a radial arm) are more or less fine; the water is thrown in the plane of the blade and the guard tends to keep it close to the plane of the work.

Drills can be kept dry. Gotta use the correct bits; you may think you can control the feed speed to compensate, but not reliably.

Grinders and sanders have to be used dry. Belt sanders not so bad for overheating, given a light hand.

I did a set of 17 press-in 3/8" acrylic storm windows for an old house. Made a cutting guide for the radial saw which made the work fast and easy, if not so dry. The saw rode on the guide, so no scratches; and the thing automatically set the offset for easy layout and accurate cuts.