Acrylic Router Bit Question

For a saw blade probably one with negative hook. For sure don't use one with a lot of positive hook. You can get bits for cutting plastic and the flutes are described as "O" flutes. Regular bits will cut the plastic but I've had them grab once in while and it usually knocks a chip out.

My experienced Carpenter Brotherinlaw says to reverse your saw blade when ever cutting plastic this helps to reduce chip out please chime in my friends with your thoughts on this please.

Reversing the blade would give it the negative hook I mentioned but it presents another risk. In normal operation the teeth on the blade are supported by the body from behind. When you reverse the blade all the pressure is on the welds so it is possible for the blade to lose teeth when you reverse it.

I think that's pretty dumb because it will generate a lot of heat (friction) and then one thing you need to do when routing acrylic is to keep the temperatuers down - when it all gets hot swarf will just end up welding itself back onto the surfaces giving you that wonderful "shotblasted with rocks" look..... Use a fine tooth carbide sawblade with a zero or negative rake on the saw - for small quantities a jigsaw with a wavy set metal cutting blade works well but requires a bit more clean-up. For the router try to go to a spiral cutter. You don't need solid carbide on acrylic - HSS (which is far cheaper) will do and is what the industry used from the 1930s right up until the 1990s. Just keep the revs down and the feed speed up - the idea is to cut chips, not create "fuzz" - and use dust extraction if at all possibe because the airflow not only reduces weld-back, but also hepls keep it all cooler