rotting rubber

[cncjerry]

I don't understand how the world got to this point with rubber and rubber coatings.  I'm talking about the rubberized coatings on things like binoculars, some portable electronics, etc.  Also, certain plastics exhibit the same characteristics.  I have 4 or 5 guitar holders and two of them have clamps that split at the screw holes when the plastic melted, for lack of a better word.  This caused the guitars (a dual stand) in one case to hit the floor.  For the longest, time I thought it was related to the hand lotion my wife uses, but that didn't make sense.  Didn't stop me from blaming her! 

Yesterday I bought another DAT audio deck, can't have enough tape decks, and it was failing.  I was told "it worked yesterday!" That was a load of crap because when I opened it up, the load belt was mush.  Just picking it up caused it to fall apart. This was a rubber belt the size of a rubber band you would used for teeth braces.  I found them online, but wanted to test the deck in the worst way, so I pulled the o-ring out of a pen flashlight and stuck it on, and it worked!  I have two other DAT decks, both have issues with the pinch rollers related to the same gummy problem.  I collect calculators with mag card readers and they have the same problem.  In their case, I scrape the gum off until I get to the hub and then used small o-rings.  This trick also got my Sony dat deck working temporarily until the new roller came in.

I see people clean this gunk off using IPA at stronger concentrations.  I've tried it, it's a lot of work and it leaves the finish looking horrible, better than being gummy, I guess.  But given the world-wide extent of the problem, it seems like consumers collectively sort of got screwed!

This problem seemed to show-up about 10yrs or so ago, which means whatever process was being used starting about 20yrs ago kicked this off.  I don't remember it being this bad when I was younger. 

Comments?

Jerry

p.s. and don't talk me out of tape decks!  I use Reel to Reel on my analog setup, LTO tape on my computers, DAT tape on my digital machines.  When I was a kid a ran around recording everything onto a small cassette player. 

[shabaz]

I'm dealing with a similar problem right now! Friend's old hi-fi separates which are almost exactly 30 years old, but all the belts have perished. Hard to find the exact replacements, for instance one of the belts is supposed to be 1.2 mm square cross-section, but I can only find 1.0 mm; ordered it anyway to see if it works.

I had hoped I could have swapped out the entire CD mechanism with one from a slightly later model, but by bad luck the mechanism changed slightly for the next model, and then remained the same for a couple of models after that! : (

[floobydust]

Belts get damaged if oil or grease gets on them. Some people are sloppy doing a lube job on a machine and it ruins the belts, they disintegrate.

IPA dries out rubber, especially bad for pinch rollers.
Pinch roller when they get hard and tough I use MG 408 Rubber Renue to soften them. Essential stuff if your into mag tape. I was told not to use that on belts.

My Beyerdynamic headphones, the headband (plastic faux leather) started to literally dissolve. Leaving this black goo all over the place that ruined my furniture, it ain't never cleaning up.
I contacted Beyer and bitched and they insisted it's being attacked by hair care products i.e. conditioner. What a strange excuse. So the hand lotion could actually damage the plastics...

[shabaz]

Thanks for the tip. I've now ordered a bottle of that, pretty sure I will need it once I get to the dual cassette deck.

[IanB]

First of all, natural rubber (latex) disintegrates (perishes) with age. This applies to anything from elastic bands to car tires. I'm not sure exactly what the cause is, it is either oxygen from the air, or ultraviolet light from the sun, or any combination of those. But basically, all natural rubber products have a lifetime and eventually they will disintegrate and fall apart.

The alternative to natural rubber is synthetic rubber, but often this kind of rubber also disintegrates with age. But instead of cracking and turning into a powder, it may kind of melt and go slimy. This might be a direct result of oxidation by air, or it might be a result of plasticizers used to soften it.

I don't think there is an answer. Rubber seems to have an age limit, a useable lifetime, and if you exceed that you have to replace it.

Hard plastics also degrade with age, but the effects are limited to the surface. Since they are very dense, oxygen cannot diffuse into the interior to affect the structural integrity so much. Rubber has a kind of "open weave" molecular structure, so oxygen can get right inside it and degrade it from the inside out.

[tooki]

It’s also worth mentioning that in reality, there are (at least) three groups of relevant materials, some of which can be further subdivided:
- natural rubber (latex from rubber trees, gutta percha, etc), i.e. naturally-sourced polyisoprene
- synthetic rubber (synthetic latex), i.e. synthetic polyisoprene made from petroleum
- other elastomers (a wide family of disparate compounds including polyurethanes, silicone rubbers, silyl-modified polymers, plasticized plastics, and many more)

A lot of the materials we colloquially refer to as “rubber” are in fact some kind of non-rubber elastomer.

The first two likely behave quite similarly as they age (given a particular type of processing), but each elastomer will age differently, and it’ll also depend on how it’s processed. (E.g. cross-linked polymers are likely more durable than ones that aren’t.)

[Bobson]

Blue rubber coating used in CEM DT-9979 and Agilent U1252A deteriorates with the age leaving white hard residue. Strangely enough, old Escort DMMs with grey rubber do not have the problem. Also, do not see any problems with Fluke's rubber.

[Haenk]

I guess that's the price of industrializing products.
A longs time ago, leather was used as "grip" material - that will last for centuries, but is quite expensive and obviously does not work with "modern formgiving".
Actually, I only have *one* single item with a leather grip, that's a PICARD geology rock pick. As such, quite an expensive item, with platstic instead of leather grip, they cost waaaaay less.

[tooki]

I guess that's the price of industrializing products.
A longs time ago, leather was used as "grip" material - that will last for centuries, but is quite expensive and obviously does not work with "modern formgiving".

Leather certainly can be form-fit to quite complex shapes. Think about shoes, steering wheels and shift levers, and things like phone cases. (I had one from Apple that was a thin plastic shell with leather stretched and glued tightly, with no seams at all, making a 180 degree bend over the rounded edges, including the corners.)

[Haenk]

Leather certainly can be form-fit to quite complex shapes.

Outer shape, yes, but not usable for structural parts. Plus the rather small-ish supply. Plus difficult to process in an industrial scale.

[GLouie]

Yes, such man-made materials seem to run the gamut of longevity, requiring painful vigilence.

I also have a rant with polyurethane foam, commonly used to pack delicate devices. They usually turn to goo after a decade or so.

[tooki]

Leather certainly can be form-fit to quite complex shapes.

Outer shape, yes, but not usable for structural parts. Plus the rather small-ish supply. Plus difficult to process in an industrial scale.

The footwear industry would beg to differ. It makes complex-ish structural leather goods at industrial scale. Not sure why you’d think this is impossible or even uncommon.

[Coordonnée_chromatique]

My mother sewing machine of 1972 that have a tooted cotton belt in a perfect condition since 1972.

[Doctorandus_P]

I'm also quite annoyed by the "soft plastic" / Rubber / TPE on toothbrush handles, drills and all kinds of other hand tools. I don't buy srewdrivers and pliers from Wiha anymore for example. The quality of Wiha tools is quite nice for the metal parts, but the soft plastics is a mess.

Another nuisance is the stuff that gives plastic a "velvety" feel. Those also always get damaged and peel of after a few years. I have even have some transformers in a plastic box and rubber feet, and the rubber feets literally turns into liquid and drips off and makes a mess of everything it touches. Real yucky stuff.

Sometimes I guess it's somewhere in between "the factory does not care as long as it looks good when it's still in the shop" and planned obsolescence.

I've also heard that the old space suits used for the moon landings are now very delicate museum pieces that almost fall apart when they get touched. Longevity was probably never a big concern during production of those things, but their degradation is nonetheless quite remarkable.

[Messtechniker]

p.s. and don't talk me out of tape decks!  I use Reel to Reel on my analog setup, LTO tape on my computers, DAT tape on my digital machines.  When I was a kid a ran around recording everything onto a small cassette player.

Just for kicks: do an echo with a tape machine and compare it with a digital echo.
Which degrades faster? Just to give you an idea how bad analogue tape copies can be.