[Amps] Use Caution when using Silicon Dielectric Greases

[Jim Thomson]

Date: Thu, 5 Jul 2018 22:15:51 -0400
From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
To: "amps at contesting.com" <amps at contesting.com>
Subject: [Amps] Use Caution when using Silicon Dielectric Greases
Message-ID: <c163d4f4-1cf6-7391-4d0f-0a592ccc4c61 at 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