silicone rubber?

[lowell]

i'm curious what exactly the clearish rubbery stuff is that we find on caps inside amps, its purpose is to stabilize the physical movement of the filter caps I believe.

[loudthud]

One of the common names is RTV which IIRC is Room Temperature Vulcanizing. Commonly sold as bathtub sealer. It's basically to hold parts in place against vibration but it's still easy to replace the parts when you need to. It contains Acetic acid so it can attack some plastics. The one case I suspect it did some damage was to a surface mount resistor and it took about 5 years.

[Mark Black]

Hey loudthud thanks for the meaning behind the initials "RTV". I never really knew what it stood for but never was curious enough to research it.

Another characteristic of RTV/Silicone Sealer which is not perhaps readily apparent is that it's somewhat conductive until it fully cures (especially with high voltage applied - hard lesson learned there...).

[Tom Phillips]

There are also special "electronic grade" RTV products available. As an example, you can see the specification sheet for one company's product at http://www.relicom.ru/fileadmin/catalog/RTV16X.pdf
Cheers,
Tom

[jrfrond]

RTV is great stuff, but bitch to remove. Hence, I prefer to use hot glue, provided it is not in an area which gets overly hot.

With hot glue, if you need to remove it, you just hit it with a little freeze spray, and it pops right off.