I see people talking about how their belt turned to mush. I don't understand this. Why would tape belts turn to mush, but other rubber products don't? Rubber dries out and cracks, but I've never seen it turn to mush.

The chemical compound destabilizes over time and temperature. Humidity also plays a role, the softer the belt, the less wow and flutter since the belt will absorb most of the mechanical shock, but also the softer the belt means it will be easier to break down.

Don't forget, the technology was mostly precomputer, so modeling the life of the belt was never really an option......hell if it lasted 10 years, that would be a good service life.

Hell some of these radios are pushing 30-40 years of age!

Also, Windex will almost instantly eat the belt on contact, so if you have a melted belt situation, just use windex to bring it back to absolute clean and install a replacement belt........that is my experience on this issue of changing over a few hundred belts.

So tape belts contain a different, more fragile rubber compound than other rubber products?

Belts come in many different compounds, it depends on where they got the supply from and what the specification was at the time.

Could be from sitting for long periods of time using the tape function can help.

The chemical they use to clean the belts before they leave the factory and heat.

one of the compounds of belts is oil in a particular form....basically the belts end up back at the first stage of manufacture......oily goo

I've seen that 'goo' in a couple of post 80's box's.,heat factor also in some if not all boombox's,and just not playin cassette's.On the walkman's though belt's snap i have not come across that with my collection,but then again i guess my player's are not as vintage as the next guy's sorta speak.

Yeah, aiwa are the main culprit here. Never had a panasonic belt go yet. Just show`s ya.

I have also wondered why some belts turn to mush. I've had a box whose belt had morphed into the stickiest, blackest substance you can imagine. It was like tar without the smell.

I've seen belts and pinchwheels/rubbers turn into a runny liquid due to chemical contamination breakdown.

In this case, it was caused by Xylene fumes in the room when a tech was servicing/cleaning some piece of gear, and the next day EVERY machine in that room had stopped.
I still have some of those rubber fittings at home, (some 20 years later) and it's still runny, like road tar.

On the home front, i've seen similar problems, mainly with boomboxes in garages, where a variety of chemicals (petrol/gasolene, thinners, turpentine etc etc) have enough fume vapour to eat away at the rubber.

Several of my bicycle tyres and the rubber "rim-tapes" had split and perished merely by the presence of Mineral Turpentine fumes within my garage (i use turps a lot for cleaning/degreasing bike parts)....

Hope this helps people be more aware of the fumes in their garages etc.

Marty.

I think because of age

quote:

Originally posted by walkgirl:
I think because of age

Yes, age will cause drying & cracking of rubber parts, but when rubber turns into a dripping wet goo then that's another issue

I have read that the original source of the belts could be a huge contributing factor. Has to do with the manufacturing process. Chinese companies supplied belts that were not cured for the requisite amount of time before being released. Apparently, the duration of the curing time is supposed to be essential to the long term stability of the rubber. Presumably in the defective belts, the suppliers cut the curing time short to save time/money and increase productivity. While the product looked good and performed fine initially, over time, they began to disintegrate and turn to goo. Belts that were properly cured did not exhibit this problem.

I have noticed that Sanyos in particular have this problem. But I suspect that any manufacturer that obtained belts from these same sources will have this issue.

Ya it was the belts from the early 80's.
I have a Hitachi cassette deck from the early 70s with the original belts.
There worn but dident turn too goo.

quote:

Several of my bicycle tyres and the rubber "rim-tapes" had split and perished merely by the presence of Mineral Turpentine fumes within my garage (i use turps a lot for cleaning/degreasing bike parts)....

Hope this helps people be more aware of the fumes in their garages etc.

Marty.

That is a good tip, thanks!

quote:

Originally posted by Reli:

quote:

Several of my bicycle tyres and the rubber "rim-tapes" had split and perished merely by the presence of Mineral Turpentine fumes within my garage (i use turps a lot for cleaning/degreasing bike parts)....

Hope this helps people be more aware of the fumes in their garages etc.

Marty.

That is a good tip, thanks!

Or contact cleaner / electronic cleaner solvent trying to evaporate in a semi closed space.... another case of why a boombox really should be disassembled before spraying cleaner. Too often, I've seen the inside of the tuner glass and cassette doors of boomboxes smoked or whitish film residue, probably from fume vapors.