Topband: More on dielectric greases

[Tom W8JI]

> Tom, W8JI wrote:
>
> "Dielectric grease has been used to preserve electrical connections in low
> pressure connections and high pressure connections at least since the 
> 1960's
> or early 1970's."

Roger VE3ZI replied:
> Possibly even earlier than that. I spent a small part of my misspent youth 
> (~1961) in a TV repair shop. The TVs of that era (in the UK at least) had 
> large rotating turrets to select the channel. We used to burnish the 
> contacts with 'Silvo' and then smear silicone grease over them. That part 
> of the set was then much more reliable than as supplied new. The remainder 
> of course, was not!
>

Besides the tuners, which used silicon grease on silver plated contacts, it 
was also used on PC board contacts on modular TV sets. The grease 
**prevents** wear of the plating, expending life. It is not abrasive.

There is a key difference between Mike's application and TV set 
applications. The difference has nothing to do with silica or silicon grease 
being abrasive, unless Mike had some unusual type of grease.

Greases should generally ***never*** be used on connections that have 
significant voltage and arc in transfer, unless a manufacturer specifically 
requires a grease. GE requires relay contacts in some diesel locomotives to 
be coated with a GE grease, and there are probably more examples of 
exceptions. In general, hot-switched connections that arc during switching 
should not have any lube or grease.

73 Tom