Thermal degradation of vinyl and its expected lifetime?

Discussion in 'Audio Hardware' started by Publius, Jun 6, 2007.

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  1. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    This is going to be a long and somewhat detailed post, so I'll put a summary here: vinyl is believed to degrade over a period of decades/centuries, even when not played, according to well known chemistry reactions. Why don't people worry about this?

    From "The Care and Handling of Recorded Sound Materials" by Gilles St-Laurent, Music Division, National Library Of Canada:
    Thus far, vinyl has proven to be the most stable of the materials that have been used in the manufacture of sound recordings. However, although stable, its life is not indefinite. Pickett and Lemcoe, in Preservation and Storage of Sound Recordings, states that "failure by chemical degradation of a vinyl disc in ordinary library environments should not occur in less than a century"... Polyvinyl chloride degrades chemically when exposed to ultraviolet light or to heat. Phonograph discs are exposed to high temperatures during moulding and pressing. Unless stopped, this heat would be a catalyst for ongoing dehydrochlorination, which is the release of hydrochloric acid (HCl) from the PVC as a result of thermo-degradation. Stabilization is therefore achieved by adding a chemical to the resin during manufacture. This does not prevent the degradation but controls it, mainly by consuming the free HCl. Sufficient effective stabilizer remains in a plastic phonograph disc to protect it for several decades after pressing.
    This link gives a good overview of the primary mode of thermal degredation through HCl, zip dehydrochlorination. In the of heat, any free hydrogen chloride in the vinyl solid helps break off more HCl from the vinyl monomer. This HCl also aids in several other modes of degredation; look at the page (and the pages it links to) for more details.

    The heating of the vinyl during pressing is enough to kickstart the degredation. So stabilizers are added to grab any free HCl, be substituted into the vinyl monomer when any HCL does break off, etc. But clearly, there can't be enough stabilizer in vinyl to capture all of the HCl. Eventually, the stabilizer runs out, and the vinyl will start to decompose. It appears that when this occurs for other PVC applications (roofing/etc) this results in a considerable amount of discoloration and changes in mechanical structure (link).

    Here's another quote from The Care of Grooved Recordings:
    The consequence of thermal cycling is that each cycle of temperature change results in a small, irreversible deformation. These deformations are cumulative.... Store discs at a stable, maintained temperature of between 15EC and 20EC. The fluctuation of temperature should not slowly vary more 2EC in a 24 hour period. The relative humidity should be maintained at between 30% and 40% with a slow fluctuation of no more than 5% in a 24 hour period. ​
    In other words, the best place to store your records is in a wine cellar. The link does not give any more detail on what exactly occurs with thermal cycling, but I can only assume it's a different process from dehydrochlorination. Perhaps the thermal coefficients for PVC and the other additives are different, and the different rates of expansion introduce pops/ticks into the recording. I dunno.

    For me, this means several things:
    • Lack of temperature control may be a cause of degraded vinyl quality. Perhaps this could be responsible for ticks and pops in otherwise good-looking vinyl, if it has been, say, left in a garage for a few years. If anybody has access to a thermal cycling apparatus, this could be pretty easy to test, actually - run an accelerated heating/cooling test on a record, do before/after needle drops, and listen for differences.
    • Keeping records in my house isn't fully adequate, because I turn the thermostat 5-10 degrees up during the day, and even if I didn't, I have poor temp control where the records are stored (2nd floor of a house).
    • Even at the optimal temperature, vinyl simply isn't inert, due to the stabilizer eventually running out. Therefore it cannot be an investment that is guaranteed to last beyond only a few generations.
    It's worth noting that I'm not aware of any concrete descriptions of audible effects of thermal degredation. Nevertheless, it's something that we know exists, so we should be watching out for it.

    I already know that there are plenty of cases of people playing back 1950s-era LPs that sound dead quiet; I'm not interested in that. What I want to know is:
    • how long records are expected to last nowadays? And how do we know this?
    • are we not paying enough attention to how we store our vinyl?
     
  2. VinylNutz

    VinylNutz Active Member

    I can't answer your questions but thanks for the interesting information. I hope someone hear may know some answers.
     
  3. Frumaster

    Frumaster New Member

    Location:
    Georgia
    Well, that info is new to me. One positive thing to consider is that playback technology and cartridge design has been greatly improved, which should prolong the life of vinyl somewhat. As far as thermal degrading goes, what about when you play a record...doesnt the friction between needle and the groove cause a very fast, severe temperature change?
     
  4. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    Long story short, no. The stylus is believed to heat up to over 300-500 degrees due to the constant friction from the groove. The vinyl does in fact melt as the stylus presses onto it, but that's more due to the large pressures involved than due to any large temperature.
     
  5. stevemoss

    stevemoss Forum Resident

    Something tells me the next thing we'll see are thermally regulated turntables - with a cooling element under the platter itself (and perhaps even a heat-absorbing slip mat), and a mechanism to blow cooled air down a hollow tone arm onto the stylus, or up a hollow spindle onto the record. ;)
     
  6. Surfin Jesus

    Surfin Jesus New Member

    Location:
    NYC USA

    doesn't the vinyl need to melt in order to prevent permanent damage to the groove?
     
  7. stevemoss

    stevemoss Forum Resident

    I'm not certain - but wouldn't the melting constitute damage to the groove (if the melting results in erosion/reduction of the information encoded in that groove)?

    Seems to me that if cooling at the point of contact would lessen that effect, you'd be able to retain more integrity to the encoded signal... kind of like the way they water-cool high-friction industrial cutting machines (so that what they're cutting doesn't uncontrollably melt/deform at the point of contact).

    And if what Publius is saying is true, then extra heat accelerates the breakdown of the vinyl...
     
  8. DragonQ

    DragonQ Forum Resident

    Location:
    The Moon
    While I think it's fair to say that Vinyl is "the most stable of the materials that have been used in the manufacture of sound recordings", it definitely isn't the most stable of formats. I would say it was until fairly recently, but with the ability to losslessly rip any CD you buy, make exact copies/backups on other CD-R(W)/DVD+/-R(W)s, as well as storing it on any number of main and backup Hard Drives etc. means digital audio clearly has more promise in terms of lifetime than analogue audio stored on Vinyl.

    I'd like to see a graph showing the degredation of sound per listen to a standard vinyl LP, but it would be almost impossible to measure that objectively. :(
     
  9. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    It could be construed as damage, but out of all the damage mechanisms, it's by far the safest.

    Alas, I read all of the following quite recently, but I forget where I read it. I'll need to dig up the reference. It might have been an old issue of the BAS Speaker.

    If no deformation occurred at all, and the record was perfectly rigid, the pressure on the groove would rise by a HUGE amount - perhaps 10x or so. This is enough to vaporize the stylus. Apparantly, this can actually occur if you play a positive stamper or DMM mother with a regular stylus.

    Also, the truly sure-fire way to ensure that the groove stays cool during playback is to play the record wet. And most of the sound quality problems ascribed to wet-playing are due precisely to the fact that the liquid prevents the groove from melting. IIRC, the same thing happens when a positive stamper is pressed wet.

    Melting = good.

    Actually I'm saying that the extra heat, while it does have an effect, is rather minor in the grand scheme of things. What I'm wondering about is if the damage you impart to your records by storing them in your air-conditioned home may be greater over a period of years/decades than playing them back a few times.
     
  10. stevemoss

    stevemoss Forum Resident

    Oh my...
     
  11. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    OK, "air-conditioned home for a few years/decades" may be a bit too inflammatory. A more specific and realistic case would be years/decades in a record shop whose A/C is turned off when closed, or a garage, or anywhere with temp fluctuations in the 5-20 degree range. Or a air-conditioned home with the highest quality temp control, over a period of many decades to centuries.
     
  12. stevemoss

    stevemoss Forum Resident

    Okay...I understand your wine cellar analogy now.
     
  13. nin

    nin New Member

    Location:
    Sweden

    Sorry, that I don't believe one second in. I have not seen ANY proof for this. I can give you proof that it IS NOT SO. In the 90's there was a big cartridge test here in Sweden and one of the test was wear test. They pressed vinyls with only one groove and played it. The cartridge that gave the lowest wear was the OM-40, and they played the same groove for 48 000 times during one day. No problem whatsoever with warm vinyl because of friction at all, and only small amount of wear could be seen.

    So I would guess this is little "pseudo-hifi science", something that haven't really been proven at all.
     
  14. Surfin Jesus

    Surfin Jesus New Member

    Location:
    NYC USA
    as I understand it, after the needle passes, the vinyl reforms back (unmelts) to its original state (more-or-less)


    what exactly don't you believe?

    the vinyl isn't "warm" after play because it solidifies as soon as the needle passes over it

    I also think publius was fairly accurate in his statements (approx. 16000 PSI pressure causes 300F temp)

    I'm dying to see your proof that the vinyl doesn't momentarily melt during play, though - please share this non-"pseudo-hifi science" that proves "it IS NOT SO"! :wave:
     
  15. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    Oh, and while you're at it nin, disprove several AES articles documenting vinyl melting behavior under normal playback conditions. I can provide those references too.
     
  16. nin

    nin New Member

    Location:
    Sweden

    Prove it.
     
  17. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    OK, but only in a separate thread. You're welcome to start it for me, otherwise I'll start it myself.

    I still don't have answers to the questions I was actually asking, just mostly off-topic posts:
    • how long records are expected to last nowadays? And how do we know this?
    • are we not paying enough attention to how we store our vinyl?
     
  18. MikeyH

    MikeyH Stamper King

    Location:
    Berkeley, CA
    Hmm..

    I have, and see, a lot of records from 'the dawn of vinyl' - say 1950-55. I have yet to see any that have spontaneously ceased to be records, so the easy answer is 'more than 55 years'. I do have records that have been played by me more than 250 times (that's when I gave up counting) on reasonable equipment. While that record sounds fine, I did replace it with a 'nos' copy of the same vintage which sounds interestingly better by a small amount. Playing and (mis) handling, including poor storage, are what stops records lasting, not long-term chemical instability.

    In my own (30yr+) collection, the bugbears are firstly accidents, secondly normal house bugs (eating parts of one or two paper inner bags out of thousands, maybe more I won't notice for another few years) and glue failure (inner bags and card covers). Storage has been in normal house living conditions - no damp, cold or heat.

    I know they did 'accelerated aging' tests on CD. Has anyone tried any on vinyl records (other than playing thousands of times)?
     
  19. Tim S

    Tim S Forum Resident

    Location:
    East Tennessee
    Under ideal conditions (proper temp, humididy, upright storage, exposure to light) your own links say at least 100 years. This is a conservative estimate, imo. I am an archival studies student so I have SOME knowledge of this, but I am a STUDENT that just happens to read and study the subject a lot. I have seen other estimates of several hundred years under these conditions. Average them out, you get, basically, a couple hundred years.

    How do we know this? Usually from tests conducted to simulate the aging process and measure the results.

    Are we paying enough attention....?

    That depends on how much any single person cares about the longevity of his or her collection, doesn't it?

    Common sense: storage and environment = long life
     
  20. scuzzer

    scuzzer New Member

    Location:
    Colorado, USA
    I think the above two posts covered your first question quite well. As for the storage issue, you also have to remember that most records are stored packed together side by side forming one big block of vinyl and cardboard. Although the air temperature in the room may change by 10 degrees the vinyl itself is probably remaining within a degree or so of the average room temperature.

    As to the off-topic posts, there is some interesting information here: http://db.audioasylum.com/cgi/t.mpl?f=vinyl&m=589864
     
  21. stephenlee

    stephenlee Forum Resident

    Location:
    East Coast
    Solution to all possible temperature-related problems/damage from playing vinyl records:

    The ELP laser turntable.

    Hey, they're down to only $9,900 now! :D

    http://www.elpj.com/about/news.html
     
  22. Surfin Jesus

    Surfin Jesus New Member

    Location:
    NYC USA
    I believe you were asked first
     
  23. HGN2001

    HGN2001 Mystery Picture Member

    Great...another controversy...vinyl warming...

    :sigh:

    Harry
     
  24. Publius

    Publius Active Member Thread Starter

    Location:
    Austin, TX
    I wasn't expecting records to spontaneously decompose. In fact, even after all of these chemical processes, I'd guess that the record would still be playable. I'm more worried about reductions in sound quality - an increase in pops, ticks, and background noise. This wouldn't yet show up in any manufactured record, properly stored, because the stabilizer hasn't run out yet.


    Thanks for the information; do you have any references for the actual studies? I'll be making a library run later this summer so I'll take anything you know of.
     
  25. Surfin Jesus

    Surfin Jesus New Member

    Location:
    NYC USA

    I don't see the need for controversy, myself, though apparently some feel that the occurrence of the needle momentarily melting the vinyl is "pseudo-hifi science", despite being documented for years in numerous places

    they also offered to prove "it IS NOT SO", though they quickly retreated when challenged and have still not presented the proof they claimed to have

    so, no real controversy - the only questions, really, are what are the easiest and best ways to prolong the life of our vinyl records in regard to storage
     
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