[TowerTalk] RTV? What Kind?

[Jim Lux]

Michael Keane K1MK wrote:

> The other thing about using RTV is that RTV needs 
> to be exposed to moisture to cure. So you don't 
> want to cover up RTV with anything like tape or 
> other sealants at least until the full cure time 
> of the RTV, otherwise the RTV will never fully harden but rather remain tacky.


I believe this is only true for the one-part RTVs..  the two part RTVs 
do not require exposure to moisture, and tend to outgas less.

I suppose it comes down to whether one wants caulk or a potting compound.

Either type is available from the usual mail-order sources (Newark, 
Mouser, Allied)

MG Chemicals is the new company that handles what used to be GE 
silicones. http://www.mgchemicals.com/products/silicones/guide.html

Walks you through which one you need (then you can hope that the minimum 
quantity isn't a 55 gal drum).  They cover things like thermal 
conductivity (important for some applications, e.g. potting a balun or 
HV power supply), cure types, etc.

For instance, a 2 part RTV12 is intended for electrical potting, is 
primerless, and translucent and fairly runny (1500 cps).  RTV11 is much 
stiffer, white, and much harder after cure.