Silicone is totally different from silica. Silica in its most common form is
"sand". Silicone is a name for a class of compounds based on the element
silicon. The properties can vary significantly. Silicones are commonly used
for lubrication and defoaming applications. 73, Greg-N4CC
Sent from my Verizon Wireless 4G LTE Smartphone
-------- Original message --------
From: Tom W8JI <w8ji@w8ji.com>
Date: 11/24/2013 6:11 AM (GMT-07:00)
To: Mike Waters <mikewate@gmail.com>,topband <topband@contesting.com>
Subject: Re: Topband: Verifying integrity of 75 ohm coax.
> 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.
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