White Compound on Electrolytic Caps

[paulstevens]

Hello, what is the white compound used to "glue" capacitors down to a board so they don't vibrate? Is it RTV? Does it have an official name or function?

What I am really asking is what can I use to replace it when I find it broken or cracked on boards I am looking at.

Thank you.

[stj]

Re: White Compound on Electrolytic Caps

it's neutral-base rtv
be carefull because the cheap stuff sold for bathrooms is either acid-base or alkaline-base and will do damage.

you dont really need it.

[paulstevens]

Re: White Compound on Electrolytic Caps

Thanks. I'm working on a Yamaha RX-A3050 and have the Digital PCB out. The RTV securing one of the two giant electrolytic caps on the power board has cracked, and I can rock the cap back and forth. I was planning to remove the power board to verify the solder joints of that cap (and the others) and wanted to fix it right, hence the question about the RTV.

If I don't need it I probably won't bother with it.

Why is it there? To keep them secure during transportation? Or some functional reason?

Thanks.

[andrewsawesomr]

Re: White Compound on Electrolytic Caps

Why is it there? To keep them secure during transportation? Or some functional reason?

It's usually there to prevent cracked solder joints/damaged components from occurring during the shipping process or from vibration from something like a transformer.

[diif]

Re: White Compound on Electrolytic Caps

It's also added to aid in manufacturing, holding components in place for soldering.

[paulstevens]

Re: White Compound on Electrolytic Caps

Thanks everyone. I appreciate the help and info!

[Galraedia]

Re: White Compound on Electrolytic Caps

It's non acidic silicone glue. You can find it on places like eBay using terms such as "thermal adhesive" or "heatsink plaster". It's used to hold components in place, insulate them from dust and moisture, and used as a thermal adhesive between chips and heat sinks.