Resufacing CDs, how to?

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I've recently bought a new CD transport. I'm generally pleased with it but find it rejects CDs more than the old DVD player I used before. About 12 so far. And I can see why... they've got some decent scratches on them. So...

I want to resurface my CDs to remove the scratches. Searching the internet I've come up with this...

Using wet-dry sandpaper with water
- 1500 grit then,
- 2000 grit
- 2500 grit
- 3000 grit

After sanding up to 3000 grit you then use a rubbing compound, like a 3M product you'd use on your car followed by wax. The same wax you'd use on your car, applied the same way.

Before I start sanding my CDs (I'll try only one first) I thought I'd ask...
Has anyone done this before?
How high did you go with the sandpaper? Higher than 3000?
Any advice?

Thanks,
Glenn
 
Since you own the CDs, you could just borrow your local library's copies and legally record your own copy.
That's a lot easier than all that sanding, which may not work, and will take a lot of time. Even buying
a new copy is cheaper than what your time is worth.
 
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I would rather buy a new player.
Theoretically, scratches totaling up to
6mm should be playable. One single 6mm scratch would not
work, bit for example 4x1,5 mm. Some
CDM-1 equipped players from the beginning
of the Cd-era manage this. Btw, polishing is sufficient.
Even though the CDs are Polycarbonate, acrylic polish should work
 
Some of them (Stones, Rush) I know that I can borrow from the library. I'll do that for sure. Others like Mad Scientist and Faust, I think I'll need to fix.

Salar...is that your name? My son's name is Salar (it means leader in Urdu.) I didn't know about acrylic polish...seems like a good idea. Actually looking up information about acrylic polish led me to a number of sites that were about headlight restoration kits. That might be useful, very similar task.

I fixed one CD by just coating it with microcrystalline wax. It now plays fine at home and in the car...
I'm determined to resurface them myself. I'd seen a couple of products online but I'm more comfortable doing the sanding myself.
 
I think the right sort of wax can fill in the cracks and cause no further damage - remember the disc surface needs to be locally optically flat, using any abrasive sounds like a big mistake. Just filling the cracks with a suitable transparent filler designed for the job is probably the safest approach.

Since CDs are polycarbonate you have to be really careful in choice of any solvents or oils as polycarbonate is very sensitive to many of them being completely destroyed by many of them (for instance lemon rind contains an oil that is polycarbonate-incompatible as I found out when a storage jar started dissolving on the inside exposed to the vapour).
 
Here's what I ended up getting.

1st step:
Clear plastic cleaner & polish (a little abrasion.) Meguiar's PlastX.

2nd step:
Brazilian carnauba wax. Wax to fill in the tiny little lines. Mothers.

I also got sandpaper but so far this 2 step process has fixed all 5 discs that I've tried it on so far.

Thanks,
Glenn
 

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Indeed, as per Salary I threw away a Led Zeppelin CD and a Sheffield Lab CD and replacedthem many years back. A friend had borrowed them, and left them on the floor, and a walking rug of dogs (Pekingese) walked all over them. Scratched beyond repair.


However, I have a question about discs that have not been "centered" properly. One can actually hear the disc's eccentricity. I just don't play them anymore because they are likely to mess up the motor bushings etc. I even bought a new one and that was the same. Obviously a duff batch. I know there are gizmos available to rectify the problem, but they are pretty damn dear. Any suggestions, apart from an engineering shop.


Kevin


P.S. I wash every single CD I buy before first use. I use a generic washing liquid and a microfibre cloth to wick away the water. Without fail every single one still has some release agent still on the surface.
 
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Correct name

Indeed, as per Salary I threw away a Led Zeppelin CD and a Sheffield Lab CD and replaced them many years back. A friend had borrowed them, and left them on the floor, and a walking rug of dogs (Pekingese) walked all over them. Scratched beyond repair.

However, I have a question about discs that have not been "centered" properly. One can actually hear the disc's eccentricity. I just don't play them anymore because they are likely to mess up the motor bushings etc. I even bought a new one and that was the same. Obviously a duff batch. I know there are gizmos available to rectify the problem, but they are pretty damn dear. Any suggestions, apart from an engineering shop.

Kevin

P.S. I wash every single CD I buy before first use. I use a generic washing liquid and a microfibre cloth to wick away the water. Without fail every single one still has some release agent still on the surface.


My apologies Salar - I only saw too late that I had misspelled your name. :eek:
 
Nakamichi

I've never hear of that and can't find anything about it online. I know it happens with LP's (I've seen the needle sway back and forth) and it must happen with CDs too.

I've heard of drills and rat tail files being used on LPs but I have no idea if that would be a good idea on CD...

Nakamichi made a turntable (Dragon TX-1000 circa 1982) where the top platter with spindle (~10mm thick) was on top of the main platter. There was a seperate arm that came out and the LP wa spun at a relatively low speed and the final edge of the lead-out track was monitored for eccentricity. If it was appreciably large, the direct drive stopped at the correct spot and a small electro-magnetic actuator pushed the upper platter to the theoretically correct position. A re-test was done to confirm the accuracy of the push, and if neccessary an adjustment could be done to confirm the centering.

Of course this is all based on the the fact that the lead out was quite round.:rolleyes:

I digress. I found the "lathe" that I mentioned earlier. Of course this is not just a simple lathe but also puts a bevel at the correct angle, which needs also to be treated with marker to prevent light/laser scatter. :eek:

I'm definitely not into the fringe science tweaks, but excessive vibration from a CD could quite possibly cause issues with high oversampling and the error correction couldn't it? In other words trying to interpolate when it shouldn't and vice-versa.
 
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However, I have a question about discs that have not been "centered" properly. One can actually hear the disc's eccentricity. I just don't play them anymore because they are likely to mess up the motor bushings etc. I even bought a new one and that was the same. Obviously a duff batch. I know there are gizmos available to rectify the problem, but they are pretty damn dear. Any suggestions, apart from an engineering shop.

It is not the disks, it is your player. In the beginning, Sony and many other companies
did put a spring-suspended cone slightly larger than the 15mm center-hole of the CD
on the shaft of the disc motor.
The CD pressed drown the cone when clamping and was automatically centered.
Any play/tolerance was left to the play between cone and motor shaft.
Philips did never do this and by today, no one does it. Saves Costs.
The cone is fixed and allows play of 1/10th of a Millimeter:
14.9 mm Diameter instead of 15mm for the CD hole are allowed.
By that, the CD does not get stuck when being loaded / unloaded i.e by expansion through warming...
 
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I also got sandpaper but so far this 2 step process has fixed all 5 discs that I've tried it on so far.

Glenn, the big problem with polishing out scratches is the raw, unprotected polycarbonate surface left behind. It's soft enough to scratch with your fingernail, and as Mark said, is sensitive to many chemicals.

Polycarbonate is the material used for most lightweight ophthalmic lenses, and we apply a hard, durable coating for protection after the surface has been fined and polished to the proper curvatures. We use a fine grit film followed by aluminum oxide slurry for polishing.

If you use abrasives of any sort on a disc, burn a back-up copy soon. It may not hold up very well afterwards.
 
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There are professional resurfacing machines used by music stores who charge like .50 per disc. Quite a few home versions you can easily find online. Ones I've had done are like new again. Music stores typically check and resurface discs as needed before resale. There is however a limit to how much material can be removed.


BTW, not sure about anyone else, but ime new CDs seem to be so sensitive that just touching them scratches. So I really don't see an issue resurfacing them.
 
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Glenn, the big problem with polishing out scratches is the raw, unprotected polycarbonate surface left behind.

I guess you are talking about the label side?:D
CD´s are and were nothing but Polycarbonate, a metal layer
(98% of all CD´s sold worldwide have aluminium but gold did also sell) laquer and
screen-printing paint. Only Blu-Rays have a protective layer as any scratch
is in the focus of the beam. So, on a CD there is no protective layer to be polished off...
 
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