...why does it appear?

Are there any possible ways to prevent it happening?

If it is some sort of dry out, can you lubricant the foam with something?

Regards,

Erik

this thread talks about it, though explanations are provided -there seems to be no complete consensus (uv, humidity, tobacco, time, quality)

Don't know why, but there seems to be two different ways they end up. Some just turn to a powder/dust.others seem to go sticky and wet.

 

Craig

Following Buranteks thread....

What I can share with you all is my parents still have the S45 beovox (yes the early 1980's range...) and they have been kept in a smoke free and dry environment, and were never exposed to direct sunlight..In fact they are still in the same house and position in their living room as the day they were purchased..... they are in mint condition 25 years on and with no sign of dreaded foam rot... in fact, frankly I still think that they sound very good ... used on a daily basis as they are.

If we were to take these as a sort of control, then we could perhaps conclude that environmental conditions do make the foam degrade faster, I would imagine as some have surmised the UV in sunlight and also smoke chemicals would speed up the chemical reaction that causes the rot in the foam. That would be why in some cases they seem to 'dry out' and some appear to 'melt' depending on their exposure. Think how styrofoam melts when exposed to certain chemicals. I would think this is more the case than a random production defect..

I think S45's have rubber surrounds though as that would explain this.

I have yet to come across any S type speakers with original foam surround which haven't suffered from rot.

 

Chris.

Hi Chris,

Unfortunately, they are not what is considered the 'better' 3 way S45-2 of the late 70s, they are the revised 2 way uniphase range from 1983 onwards... just checked online for the type no. its  6427. So I believe they definitely have the foam woofer on them....

Just thought you'd all like to hear of one set of this generation that has survived with absolutely no work on them at all! Altho given my success with recapping might treat my parents to this soon too...

 

There's no way to prevent foam rot, hoever, you van slow the process down:

• keep your speakers away from direct sunlight
• keep your speakers away from heaters
• keep your speakers in a smoke free environment

After some time, all foam rings will deteriorate. Replacement is the only option, besides buying new speakers.

 

Good Hifi