Plexiglass / Clear Polystyrene / Clear Plastics & Prototyping

A while back I remember some discussion upon the subject of
prototyping materials.

I remember relating my stories on the horrors of prototyping with
wood - the fine powdery dust getting into leadscrews and gears,
mopping up the oil and lubricatant and making a black mushy sticky
goo! Still, wood is a lot faster to cut than metal and you're less
likely to break small end-mills on it. But for all the inconveniance.

I recently started using clear-PVC/(polystyrene sheet as it's called
in the UK or Plexiglass as it's called in the States). This stuff is
great! Sure, there are a few things you should know about it - like
clamping it between two pieces of wood so it doesn't vibrate and
crack when you're sawing it, but it mills just fantastic, to a great
finish and at a very high cutting rate. The only thing, of course, it
to keep spindle speed somewhat low, so as to not MELT it and thus
cause it to stick up your cutting tool. I've not found that problem
yet - and spray it with a little WD40 as it's getting cut. The swarf
is a flakey white heap like coconut and cleans up really easily with
a vavuum cleaner (it's a lot easier if you've used WD40, since it all
sticks together in a neat clump).

Also, it's dead easy to super-glue sheets together if you need to
prototype on something slightly thicker than what sheeting is
available.

And, as a bonus, you can boast to your friends that your prototype
was made on a StereoLithography machine. :P

Just a 2p tip.