I’ve used an air powered die grinder with a diamond coated cut off wheel to
cut glass fibre re-inforced materials.
Make sure that you get the high speed version of the cut off wheel, as the
die grinders turn at very high speeds. (It may take a special mandrel to
adapt the wheel to the collet chuck on the die grinder.)
You can cut both “straight through” and “using the side” of the wheel to
smooth rough edges.
The advantages to using an air powered one, is that you don’t run the risk of
carbon fibres getting sucked into the electric motor and shorting the comutator
of the motor. Another advantage to airmotors is “the harder you use them, the
colder they get”. Check the instructions, some require a periodic shot of
oil in the oil line to keep them lubricated..(not much, or you will blow oil
all over the shop!) When you do “burp” them after oiling, aim the outlet at
the trash can, so any oil vapor is contained.. BUT AGAIN… don’t put much
in.. just a drop or two.
The VERY high speed (20,000 rpm and UP!) results in a very smooth cut. Don’t
use a wheel that isn’t rated for the “no load” rpm of your die grinder. A
wheel that flys apart is not a pretty thing. (Sheet rock walls will NOT
stop a “1/2 wheel sized” fragment.) I’ve never had the stainless steel wheels
come apart.. Ever.. and they last quite a while. Eventually they will shed
their diamond coating, a chip at a time, and get slower and slower and
SLOWER.. till you decide to buy a new one.
P.S. you can use an electric die grinder.. but they don’t have all the
advantages mentioned above.