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Thread: Interesting read on plastics degradations

  1. #1
    Join Date: Dec 2015

    Location: vancouver

    Posts: 642
    I'm danilo.

    Default Interesting read on plastics degradations

    A Curators viewpoint.. But as some regard their rubber bits and Vinyl as precious.
    Useful ?
    http://canada.pch.gc.ca/eng/1439925170961
    My audio bits: Thorens / diy phono, CD/dvd player(s), diy pre, F6, Tannoy Golds in my boxes / my xovers, and of course all strung together with basic diy Wires
    Lots of Cd's, yet more audio files, a couple of hundred semi worn Lps.

  2. #2
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 26,827
    I'm Geoff.

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    Yes. Good subject. Ageing and deterioration of plastics and rubber (synthetic or organic) is certainly an issue.
    Mr. Tact!

    Main system: MMs/ADCs/Low output MC's/One rare Japanese SUT/One scarce British phono stage/various tonearms/hefty Japanese DD TT and hefty Japanese BD TT and small British BD TT. 4 CD players/2 jitter buster/2 DACs/Valve buffer. TVC stepped attenuator or valve pre-amp or solid state pre-amp. Current dumping power-amp or either of two Class A SS power-amp or Class A EL34 valve monos or big Japanese (part Class A) integrated. Big dual concentric speakers/Smaller dual concentric speakers/Two way British compacts and full range speakers, amongst others. And too much more to list!

  3. #3
    Join Date: Jan 2009

    Location: Essex

    Posts: 15,658
    I'm openingabottleofwine.

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    Quote Originally Posted by walpurgis View Post
    Yes. Good subject. Ageing and deterioration of plastics and rubber (synthetic or organic) is certainly an issue.
    Agree - especially the use of rubber in the idler wheels of turntables, the pressure wheel of reel-to-reel tape machines, and the decoupling bushes of some pick-up arms, as well, of course, in the cantilver suspension of cartridges.
    Have you listened to this month's choice in the Album Club?

    Barry

  4. #4
    Join Date: Aug 2012

    Location: Hartlepool UK

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    I'm Alan.

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    Interesting Danilo thanks for posting
    Pinch rollers on R2R certainly can suffer from Hardening or softening, solvents normally get the blame but its interesting that UV, oxygen and humidity can also start this deterioration process

    Alan
    Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, SME 3009/2 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20 - Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Voyager Mono Block, Speakers Tannoy precision 6.4 / Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500

  5. #5
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,314
    I'm Ken.

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    Good general info.

    Surprised plasticizers were barely mentioned, especially from the nature of the source.

    People wrap a lot of things with cling film, to protect them when storing/transporting etc and it is full of the stuff, though the amount varies by brand, if its very stretchy and sticks to itself really easily, the level will be high.

    A friend was transporting half a meter of 100mm dia Polycarbonate bar in the boot of his car for me, expensive stuff and he didn't want to damage the mirror polished surface, so he wrapped it in cling film. When he took it out of the car the next day and unwrapped it, to his horror and mine it was destroyed. The surface was heavily crazed and pitted, but worse were the many (100's) of stress cracks running radially to a depth of 10 to 15mm. I knew it attacked this type of material, but I was surprised how quickly it had done its work. So avoid contact with those TT dust covers if they are Polycarb.

    A lot of people use cling film in microwave ovens when re-heating food, do they even read the instructions? When the film is heated the plasticizers can be released and transferred on contact, its ok I suppose if the film isn't touching the food, but otherwise its a no no. You don't want to be eating plasticizers, I NEVER use cling film in the microwave.

    So glossing over plasticizers is a bit of an omission, but the whole subject of plastic ageing and degradation is a complex one and you could fill a book on it, so within the scope of the article its understandable.

    Things like sun screen and insect repellent are horrible when it comes to certain common plastics. We used to do a quick test on components, using Avon sunscreen with built in mozzy repellent, as used by US armed forces etc, one of the most corrosive household substances I have come across. If the product would stand up to this, it would sail through all the proper testing down stream. One application would literally eat its way through a 3mm ABS case in two to three weeks. As we were developing items for military and aero space applications that would have been a problem.

    UV is a problem on many types and especially in plasticized grades, hence UPVC for window frames etc (U = Un-Plasticized). A new Polyprop bucket is robust and will take a lot of knocks, leave it out in the sun for a few weeks and then kick it in the evening when it has cooled down, it will shatter into hundreds of bits.

    In many ways, older products using low tech materials will outlast modern products, at least they are easier to repair and keep running, in most but not all cases.
    Last edited by Qwin; 06-06-2017 at 21:10. Reason: spelling
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  6. #6
    Join Date: Jan 2009

    Location: Essex

    Posts: 15,658
    I'm openingabottleofwine.

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    Quote Originally Posted by Qwin View Post
    Good general info.

    Supersized plasticizers were barely mentioned, especially from the nature of the source.

    People wrap a lot of things with cling film, to protect them when storing/transporting etc and it is full of the stuff, though the amount varies by brand, if its very stretchy and sticks to itself really easily, the level will be high.

    A friend was transporting half a meter of 100mm dia Polycarbonate bar in the boot of his car for me, expensive stuff and he didn't want to damage the mirror polished surface, so he wrapped it in cling film. When he took it out of the car the next day and unwrapped it, to his horror and mine it was destroyed. The surface was heavily crazed and pitted, but worse were the many (100's) of stress cracks running radially to a depth of 10 to 15mm. I knew it attacked this type of material, but I was surprised how quickly it had done its work. So avoid contact with those TT dust covers if they are Polycarb.

    A lot of people use cling film in microwave ovens when re-heating food, do they even read the instructions? When the film is heated the plasticizers can be released and transferred on contact, its ok I suppose if the film isn't touching the food, but otherwise its a no no. You don't want to be eating plasticizers, I NEVER use cling film in the microwave.

    So glossing over plasticizers is a bit of an omission, but the whole subject of plastic ageing and degradation is a complex one and you could fill a book on it, so within the scope of the article its understandable.

    Things like sun screen and insect repellent are horrible when it comes to certain common plastics. We used to do a quick test on components, using Avon sunscreen with built in mozzy repellent, as used by US armed forces etc, one of the most corrosive household substances I have come across. If the product would stand up to this, it would sail through all the proper testing down stream. One application would literally eat its way through a 3mm ABS case in two to three weeks. As we were developing items for military and aero space applications that would have been a problem.

    UV is a problem on many types and especially in plasticized grades, hence UPVC for window frames etc (U = Un-Plasticized). A new Polyprop bucket is robust and will take a lot of knocks, leave it out in the sun for a few weeks and then kick it in the evening when it has cooled down, it will shatter into hundreds of bits.

    In many ways, older products using low tech materials will outlast modern products, at least they are easier to repair and keep running, in most but not all cases.
    Oh yes - the amount of damage 'neat DEET' (diethyltoluamide, an insect repellant) can do to other plastics has to be seen to be believed. Ironically I found it completely ineffective in repelling mosquitos!
    Have you listened to this month's choice in the Album Club?

    Barry

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