This question would be best answered by Walker.
Give him a call.
Give him a call.
Walker Audio SST and E-SST dry to form a seal on the connection and protect the connection from oxidation. If you don't disturb the connection, my experience suggests that it should stay in good condition indefinitely without retreatment. (Walker Audio makes no claims about this, it's just my experience with it.)
If you do retreat the connection, Lloyd recommends removing the existing SST first (isopropyl alchohol takes it off easily), then reapply.
Silver tarnish is silver sulfide. It is conductive, but not as conductive as silver oxide. Normally, silver oxide is the concern when silver is used in electronic applications, though it's probably not such a problem for audio.
The silver in these type of materials serves to drastically lower the contact resistance at the point of connection. The effect of this is to lessen the bottleneck effect, probably by at least 3 orders of magnitude at the very minimum, electrons face at a point of connection. I believe this is most probably the reason we hear such sonic differences with these materials, as opposed to oxidation, because silver itself is not immune to oxidation.
Silver, as opposed to the seven other precious metals, is the one to worry about when it comes migration. However, it is mostly related to soda lime glass. The soda (sodium oxide) is used to lower the melting temperature of the glass, and improves the surface quality of the quenched (solidified) glass. Silver will migrate through this type of glass when an electrical current is passed through it, due to the presence of the sodium. The way to prevent this is to alloy the silver with at least one other precious metal (normally palladium or platinum), or use a different type of glass. I would think almost none of us are using the SST/ESST on glass, let alone soda lime glass, so, like the silver oxide issue, the point is probably moot.
The ONLY worry I have with these materials is that one must be extremely careful to not build up enough material (either in one large application, or cumulative applications over time) to short something out, and cause a component to fail catastrophically. Be EXTRAORDINARILY vigilant in this area - to the point of visually inspecting this after applying the material even if you have to take your gear apart to do so (if used on tube pins, tube sockets, etc.).
Yes, like Trlja said: be extremely careful with any of this stuff.
I was going nuts with some silver treatment stuff and got a bunch of it on my hands and face. Evidently I put too much on my tube pins (or maybe it was from coating the whole tube - my bad). When I installed the tubes and fired up my amp....POW! the last thing I remember was a big flash of light. The tubes exploded. I was jolted in the face with 280 volts of electricity, glass cut my face and left eye ball all up, the whole right side of my face caught on fire and burned most of my hair off. The fingers on my left hand were reduced to nubs.
My wife, who was watching in horror, tried to put the fire out by kicking me in the face over and over. Broke my nose and took out two of my teeth. We lost one of our cats in the incident too.
I hate when this happens and, I don't know if this tweak made my system sound better or not.
So yes, exercise a little caution with this stuff.
I didn't mention the 182 stitches from the glass and two fractured vertebrae in my neck from my wife kicking me. The whole thing just went wrong. Still, this turned out to be a family event so there's pictures that captured this "Kodak Moment". Let me know and I'll post them if you want.
The upside: The vender sent me a FREE replacement tube with straw of this stuff - a $17.95 value!
I had my son apply it the next go. another story...