I did something similar, but I didn't want to buy a grinder. You can buy a power drill adapter and a spiral sewn buffing wheel at Home Depot or Lowes for about $15 total. I found that the spiral sewn works better than the concentric sewn because you can apply more pressure to really work on the scratch. Then use some clear-coat/plastic car polish for like NuFinish (I think there is a generic at AutoZone called Kit for about $2) with a clean cotton cloth to polish the desired area and the buffing wheel to clear it up.
NOTE: Don't put the Kit polish on the wheel directly or you will have a nice pretty white Pollock for your room.
The trick with the power drill is not to try to hold the drill to the disc. Put the drill on a table top with the buffing wheel hanging off the edge. Then use your hand to hold the disc against the buffing wheel which allows you to control the pressure and turn/manipulate the disc.
Your warning is very true though:
"WARNING: push too hard or move too slowly and the surface of the polycarbonate will overheat and TEAR. You cannot fix a torn surface, that disc is now trash."
The heat never caused a tear for me, but I have caused the plastic to develop a smokey translucent hue which is bad and can't be recovered. When using this method also be careful with the pressure to keep from flexing the disc too much and starting a crack (usually would happen at the spindle).
Slashdot Mirror
I did something similar, but I didn't want to buy a grinder. You can buy a power drill adapter and a spiral sewn buffing wheel at Home Depot or Lowes for about $15 total. I found that the spiral sewn works better than the concentric sewn because you can apply more pressure to really work on the scratch. Then use some clear-coat/plastic car polish for like NuFinish (I think there is a generic at AutoZone called Kit for about $2) with a clean cotton cloth to polish the desired area and the buffing wheel to clear it up. NOTE: Don't put the Kit polish on the wheel directly or you will have a nice pretty white Pollock for your room.
The trick with the power drill is not to try to hold the drill to the disc. Put the drill on a table top with the buffing wheel hanging off the edge. Then use your hand to hold the disc against the buffing wheel which allows you to control the pressure and turn/manipulate the disc.
Your warning is very true though:
"WARNING: push too hard or move too slowly and the surface of the polycarbonate will overheat and TEAR. You cannot fix a torn surface, that disc is now trash."
The heat never caused a tear for me, but I have caused the plastic to develop a smokey translucent hue which is bad and can't be recovered. When using this method also be careful with the pressure to keep from flexing the disc too much and starting a crack (usually would happen at the spindle).