Do the bottoms of CDs oxidize over time

I found a copy of Tragic Kingdom by No Doubt sitting on a thrift store for $1.00. It only had one small scratch on it.

I threw it in the Mac, fired up dBPowerAmp, and ripped away. Track 1 had to do a secure rip,but all the other tracks ripped without error.

When this happens, I wash the CD with dish detergent and dry it.

This time that didn't help.

My normal next level procedure with this is that I will use ScratchX on the bottom of the CD, followed by PlastX. I rub on in swirling motions across the bottom of the CD for about a minute. I wash wish dish soap between products.

I did this, and the CD ripped without error. But it ripped easily 4-5 faster for all the tracks.

And I've noticed that newer CDs rip way faster than older CDs. But if I apply some kind of polishing compound to the bottom of an old CD, then it almost always rips faster.

So, now I am wondering of the plastic on the bottom of a CD will oxidize over time, and using some thing to remove the thin oxidized layer helps with the speed of ripping.

When I was in college back in the 80s, I remember people putting turtle wax on the bottom of CDs and buffing to a nice shine to "preserve" the CD.

 

Never seen it. Almost 40 years now. Plastic doesn’t oxidize…Good thing!

 

Sounds to me like the previous owner tried to polish the bottom of the CD and failed to remove it. I've got some old CDs that were kept in sleeves and something in those sleeves rubbed off onto the discs, making them foggy. Whatever it is is very hard to remove. I think I found that rubbing alcohol was the only thing that worked, but I have to be careful because the writing on the top side is in sharpie, which washes off in alcohol. I just have to remember to make note of the details before cleaning them.

 

I've got a Woodstock soundtrack CD with large holes in it, and somehow, with enough time, EAC can rip it. It's many many many hours though!

 

Ah the beauty of Compact Disc's ridiculously over-engineered error correction. I think CDs will outlast the hard drive you rip them to.

 

Plastic can definitely oxidize. As a result it will become discolored and brittle. Most plastic that's meant to stand up to time is formulated with small levels of antioxidant additives.

Irganox® for Plastics (basf.com)

The oxidation will be much more severe at high temperature and when exposed to light. Potentially orders of magnitude more severe. For example, the garage where I park my car requires a parking tag to hang from the rear view mirror. Over the 15 years I've parked there, I've gone through 3 of them because in the sun, they oxidized and became so brittle, they crumbled into pieces. A CD that's stored in a case in a cool environment should last for decades, but I can't say how long.

 

If it's a pressed disk (Not a CD-R/RW or anything like that) without any mistakes in it, I would imagine a well-stored CD could last for hundreds of years (It's well-protected tiny bumps in metal after all).

Does disc rot affect CDs or is it just with all the other optical disc formats?

 

I’ve experienced CD rot once or twice.

 

I have some really old CDs. I think my oldest is a 1982 copy of Hotel California by The Eagles. The play just fine. The only thing that gives away anything about the age is the CD ripping time.

A brand new CD will rip a track in 15-30 seconds using dBPowerAmp. An old CDs will take twice to four times as long to rip a track. dBPowerAmp is never forced to do a secure rip. It just takes longer to rip. I thought it might be the bottom of the CD oxidizing slightly and the laser needing to do more work.

 

disc rot is a well known fallacy
It's the manufacturing and poor quality control that creates the "rot"
batches produced by PDO in France were the main culprits of "bronzing"
and pinholes are simply a manufacturing problem.

Discs don't just "develop" pinholes.....

 

I have bought used CDs from thrift stores that had the aluminum layer full of little tiny holes in it. I bought a copy of Invisible Touch by Genesis that was like that. Looked fine in the store. Would not rip. I held it up to the light and there were thousands of little holes in the aluminum.

I know there was a pressing plant in the 90s that was pressing CDs that would stop working after just a few years. I found a website on the wayback machines that discussed it.

 

I've had Neil Young's Psychedelic Pill on CD since it was new. Both discs always worked fine until I tried to play it recently, and CD 2 was nothing but static and distortion so heavy it made the music unintelligible. Is this a result of oxidizing? I've never had that happen with any of my other CDs, including the ones that are several years older than this one.

 

A lot of vinyl purists claim that disc rot is a thing, and that vinyl will outlast CDs.

Vinyl is pretty durable when handled delicately, but analog media that requires friction contact to play a song is always going to wear out eventually.

 

My Cure - Show CD pressed at PDO is one of my disc rot culprits.

 

Hold it up to the light. Do you see small holes where light gets through. Is the bottom of the disc cloudy? Is the bottom a nice shiny aluminum or has it started to discolor?

 

This is good to know. Now I know to avoid PDO discs when I buy off of Discogs.

 

well, I have lots of discs from PDO that are good...
It's obviously a batch case-by-case thing
it really comes down to poor quality control at the facility

 

I’ve got CDRs that look awful, like an old cheap mirror.

 

I've been buying CD's since they came out. I was literally the first person I knew with a CD player. I have had not one single CD with what people call disc rot. not one. plenty of CD-r QC issues over time but not one major label pressed CD with issues. Not a single one. I've had plenty of subpar vinyl pressings. What I have had is a massive ton of horribly mastered CD's for the sake of the stupid loudness wars. Less so of the latter on vinyl.

 

The polycarbonate layer of the CD is highly unlikely to degrade considering the typical storage conditions of CD's.
A much greater risk is the use of 'cleaning chemicals' on the CD, which could lead to failure of the CD.
It is a reasonable assumption to make that CD's correctly stored and handled will last hundreds of years, possibly even a thousand years. The disc rot associated with PDO discs from the Blackburn plant in England is an entirely different manufacturing issue, unrelated to the chemical properties of polycarbonate.

 

Sometimes it can just be Neil being Neil.

 

The term "plastic" covers hundreds, if not thousands of different formulations. Certain plastics may oxidize, but polycarbonate is already in a state of relatively high oxidation, so further oxidation is really going to require some extreme conditions.

Nice post, but I do wish that we could remove the term "disc rot" from the lexicon. Rot is what happens to improperly-preserved animal or vegetable matter. None of my CDs are made of oysters, lamb or cauliflower.

But CD decay, if you will, would seemingly be more potentially related to the alumin(i)um layer. Aluminum doesn't oxidize rapidly, but it can be oxidized and if the disc is damaged in any way, that might provide a propagation site for oxidation. I have only about 3 CDs out of about 3,000 that exhibit the pinholes people mention. Two are cheap CDs and the third is, oddly, Mingus' Pithecanthropus Erectus, which I bought in about 1991 or so (an Atlantic release). Then there was the Pink Floyd/King Crimson DVD oxidation issue from a few years back from the plant you mentioned (I think that's what you're referencing). Not pinholes, but "silver mirror oxidation to a purple hue" to coin an awkward phrase. My Floyd was OK, but I needed the Crimso to be replaced.

 

Aluminium oxidises very rapidly forming a coating of protective aluminium oxide. In fact any piece or sheet of aluminium will have an outer coating of aluminium oxide. Aluminium is relatively high in the reactivity series. It is when that coating is disturbed that the pure alumium underneath then reacts. Sodium chloride, for example will disrupt the coating.

I agree that disc rot is not a great name but it is now in the language. Vast numbers of PDO CD's Made in the UK exhibit a bronzing effect, which is really obvious once you see it. As I scour the charity shops regularly here in the UK, I have come across hundreds of such CD's. I advise all to avoid Made in the UK PDO CD's from the late 80's and early 90's.

 

At least CDs don't warp in the sun!



Or do they?

 

I suppose the point I was trying to make is that aluminum ensconsed in polycarbonate isn't likely to be rapidly oxidized unless the polycarbonate layer(s) are damaged. We're on the same side here.