Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83 based; site hound.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!hound!rfg From: rfg@hound.UUCP (R.GRANTGES) Newsgroups: net.audio Subject: Re: Undestroying CD's - the whole sordid story... Message-ID: <1148@hound.UUCP> Date: Mon, 13-May-85 16:38:48 EDT Article-I.D.: hound.1148 Posted: Mon May 13 16:38:48 1985 Date-Received: Tue, 14-May-85 20:45:20 EDT References: <970@ulysses.UUCP> <935@ucbtopaz.CC.Berkeley.ARPA> Organization: AT&T Bell Labs, Holmdel NJ Lines: 32 [] Come on all you wedding guests, out there. The ancient mariner has an instructive tale to tell. I did it. I ruined two cd's by lightly scratching my initials on the of the cd with the tip of a pocket knife. I thought I was barely scratching the surface. And we all know that there is a "protective coating of plastic" over the aluminum on that side. DONT BELIEVE IT. It wouldn't protect the surface from a sharp fingernail. I was aiming to produce a very shallow mark, and in fact you need to look carefully at an angle with light bouncing off the surface to see the scratches. But the plastic is in fact incredibly thin. When you hold the disc up to a light bulb - looking thru the disc at the light - you can see part of the initials writ in the aluminum, where the aluminum was destroyed, and woth it millions of bits of info. Where the scratch is tangent to the grooves is where things reallygo to hell. So the bottom line is: CD's are much more sensitive to scratches on their label side than they are on their laser read side. Polishing won't help because its the bits themselves that are gone. An interesting sidelight is the idea of inspecting CD's like you were candling eggs. You would be surprised how bad some look and yet play. Some look like the starry skies with nearbye planets, others have scarcely a hole. So far two samples of one brand I checked were much worse than any of the other brands. I won't mention the brand because I'm not sure they are guilty, yet, but I'd bet on it. Still the discs play ok - or did until I took out my pocketknife. -- "It's the thought, if any, that counts!" Dick Grantges hound!rfg