You probably do have polycarbonate. Try taking a strip of the scrap and
bending it. If it snaps, its acrylic. If it bends, its poly. The stuff burns
well, as you found out. Flame polishing is tricky. Don't actually touch the
flame to the plastic. Just get close.
"Toller" wrote in message
...
The current American Woodworker has an article on making clear router
baseplates. And... I found a large sheet of 1/4" clear plastic at a
garage
sale yesterday. So I decided to make a base.

The plastic cut, drilled, and routed very easily, with none of the
brittleness I associate with acrylic; so I figured it must be
polycarbonate
(which I have not used before).

The article says to use either acrylic or polycarbonate, and to "flame
finish" it.
As soon as I touched it with the flame, it caught on fire! (actually I
tested it on a piece of scrap first, so nothing was lost...)

So what kinda plastic do I have? If acrylic and polycarb can be flame
finished, then I must have something different?