Topband: Verifying integrity of 75 ohm coax.

[Mike Waters]

Thanks for your thoughts on this. But all this tells me is that some
silicone dielectric greases may not be abrasive. I am certain that some
are, because I am not the only one who has experienced this.

The stuff I used was either from Radio Shack or an automotive parts store.
It was in a small gray squeeze tube. IIRC, the brand was Permatex, but I am
not 100% certain. (In my last post, I stated it was labeled "silicone
dielectric grease", but that may be wrong; it may have had "tune-up grease"
on the tube.

Clear liquid silicone oil is not the same as the translucent grease. People
have successfully used silicone oil as a lubricant for many decades.

And what kind of silver-plated rotary meter switches needed silicone grease
in order to make them last? That's puzzling. Was it grease or oil?

At any rate, silicone dielectric compound is certainly very useful in
connectors. I used to tag along with a friend of mine who worked for
Buckeye Cablevision years ago on service calls. Many of the problems were
caused by F connectors that did NOT contain the grease (Dow Corning 5
compound).

73, Mike
www.w0btu.com

On Sun, Nov 24, 2013 at 7:11 AM, Tom W8JI <w8ji at w8ji.com> wrote:

> Anything is possible, but I know what I used and saw, Tom. It was a small
>> squeeze tube labeled "silicone dielectric grease".
>>
>>
> I don't doubt your failure observations. I just doubt the cause, because
> the abrasive problem from silica is not supported. If abrasiveness were an
> actual problem, warnings or complaints should frequently appear. If silica
> or abrasives in the grease make dielectric grease bad for friction life of
> rotary contacts, it would also logically follow TV set manufacturers and
> other switch and control users or manufacturers would not use silicon
> grease in gold plated wiping contacts such as old TV tuners, in controls
> and switches, or to reduce fretting corrosion in spring contacts such as on
> automotive connectors or board connectors.
>
> As a matter of fact, when the manufacturer of silver plated rotary meter
> switches in Ameritron meter switches stopped using silicone grease the
> switches went bad very fast. Silicone liquid is also a standard meter
> movement dampener in panel meter jewels.
>
> Searches reveal use as a lubricant is everywhere, but nothing speaks of
> abrasiveness or contact damage unless an arc converts it to
> silicone-carbide.
>