Which types of silicone are ok to use?

[grizedale]

Which types of silicone should you use on an electronics PCB, and which types of silicone should you not use.?

Is it the acid based silicone which should not be used?


Also, when shoud you use RTV instead of silicone?

 

[tpetar]

You mean for heatsinks ? or you mean silicone like glue to fix something ?

 

[grizedale]

like glue mainly.

I did not know that silicone was used as a heatsinking compound?

 

[tpetar]

Yes of course.


Thermal grease
https://en.wikipedia.org/wiki/Thermal_grease


**broken link removed**

 

[grizedale]

thanks.....according to that , silicone based heatsink compound is poor.

-This confirms my belief that silicone is mainly for fixing/glueing..........maybe it sees use as a heatsink compound because it is cheap?

 

[tpetar]

No its just thermine for compound base od silicone. Silicone can be in lots of different variant.

We cant use ordinary silicone for sealing windows or doors, it must be silicone for heatsink. This silicone have good thermal conductivity.

Lots of manufacturers have their product secret, and they dont give that secret to public. But you can read manufacturer data and info linked with thermal conductivity of that thermal grease.

 

[FvM]

Is it the acid based silicone which should not be used?

Yes. To be on the safe side, you can use dedicated electronics silicone rubber. But acid-free silicone compounds are also used for a number of non electrical applications.

Also, when shoud you use RTV instead of silicone?

??? All 1-component silicon rubbers are RTV (room temperature vulcanizing).

Heat sink paste is an unrelated topic. It's high thermal conductivity is provided by aluminium oxide powder or similar compounds, silicone grease or other fluids are used as filler.