On Fri, 19 Nov 2004 10:13:13 +0000, Peter Fairbrother
wrote:

Derek wrote:

Not quite off topic, but .....

Has anyone here managed to remove scratches from CDs' (compact disks)
in a lathe?

I have a few that have been abused to the point that I can't copy them
and start over. I have tried various buffing proceedures with little
success. Any thoughts on the feasability of making a backing plate and
taking a light pass or two over the surface.

I'm a novice, so advice on chuck speed and tool shape would be
appreciated.

I don't think that would work. And flame polishing doesn't work, I've tried
that.

I thought of using cerium oxide to polish the surface, but I haven't tried
it. People use it to polish glass lenses and telescope mirrors.


I have made the kids' PS2 disks playable by polishing them with toothpaste,
and I'm told some metal polishes work too. You don't need to actually remove
the scratches, just smooth the edges of any scratches that run parallel to
the track.

You can only do this a little bit though, if you polish too much with
toothpaste you will make the CD surface white rather than clear, and it
won't play any more.



Btw, on CD's the track starts in the middle and works outwards. You probably
knew that.

Cerium oxide _might_ work. I use it to polish rocks and it definitely
leaves a high-quality surface. However I can forsee a couple of
problems. For one, cerium oxide is just about useless for getting out
visible scratches because it is too fine an abrasive. You've got to
work up to it through successively finer grades of abrasive. The other
problem, paradoxically, is that it might be too aggressive for the
plastic of the CD.

What the heck. Drag out one of your AOL coasters and try it on a flat
lap.

--RC

Sleep? Isn't that a totally inadequate substitute for caffine?