Date: Thu, 5 Jul 2018 22:15:51 -0400
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: "amps@contesting.com" <amps@contesting.com>
Subject: [Amps] Use Caution when using Silicon Dielectric Greases
Message-ID: <c163d4f4-1cf6-7391-4d0f-0a592ccc4c61@rogerhalstead.com>
Content-Type: text/plain; charset=utf-8; format=flowed
<Silicone dielectric greases work just fine as long as there is no
<arcing. If there is an arc in the grease, the grease will break down
into its constituent components, one of which is Silicon Dioxide.? This
is not a problem as long as the wiper(s) maintain a constant contact.
I've used it for years. Even used both DC4 and DC5 in ignition systems
with only one exception. After all, these compounds were designed for
and used on the ignition systems of B17s.
However, one distributor cap had a flaw and the grease leaked through to
the inside. The rotor wiper was fine, but each connection to the spark
plug wires has a tiny gap. Each gap had a "growth" of Silicon Dioxide
which eventually grew to the point where the end of the rotor hit it,
breaking off mostly small pieces which quickly ground the insides into a
mess. The same thing would happen with an RF arc.
I haven't used a roller inductor in many years, but I used Silicone
grease with no problems when I did.
For those who aren't aware, Silicon Dioxide is Quartz. Fine Quartz is a
very tough abrasive!? IIRC it was used for the Space Shuttle windows in
its crystal form which were made by decomposing HSiCl3 at high
temperature. I do not know the process was implemented.
--
73, Roger (K8RI)
## Points well taken. I found this info on W8JIs site.
https://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm
Thats an interesting read.
## Ji sez when grease arcs... it forms silicone carbide..which is highly
abrasive.
## when he mentions issues with conductive greases, he is talking about
noalox / penetrox..which is just ground up zinc in grease.
Electricians at work used this stuff called copper kote..which is ground up
copper in grease... they used it where buss bars were
bolted together.
## cool amp company also makes... conducto lube
http://www.cool-amp.com/conducto_lube.html Conducto lube is just ground up
silver
into mineral oil. spec sheet here.
http://www.cool-amp.com/new_site/product%20info/CL%20Spec%20Sheet.pdf
## They also have a msds sheet here.
http://www.cool-amp.com/product_info/CL%20MSDS-SDS%20HMIS%20Ratings.pdf
## I have never used their conducto lube product but have used their cool
amp product for years now. I silver plate everything from cu strap to cu
tubing,
and also brass machine screws, phosphor bronze and some other stuff.
Also used it on relay and contactor contacts. reduces resistance down to
zero every time.
## I had issues with brand new deltrol and also P+ B 30 A dpdt relays...
int high resistance across the contacts. Applied the cool amp goop, silver
plated em.. and end of issues.
## I also have some new heavy duty triple wafer, 14 kv, 30 A per wafer, all
wafers in parallel bandswitches that could probably use a thin layer of
something on them.
Flip side is dirt and dust will stick to grease. But I have heavy duty air
filters made by 3M.... on the intake of the hb amps..so it’s a non issue
really.
## conducto lube has the silver ground up into 3-4 microns.. but its into
mineral oil..and not grease. I don’t know anybody who has used conducto
lube..its
expensive stuff.... but does have an indefinite shelf life. Its made for
sliding contacts. cool-amp silver plating powder also has an indefinite shelf
life.
## In any case, I would not want to get any of this stuff, nor dielectric
grease onto any insulators on any bandswitches or insulation on any roller.
Jim VE7RF
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|