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[Amps] Use Caution when using Silicon Dielectric Greases

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Subject: [Amps] Use Caution when using Silicon Dielectric Greases
From: "Roger (K8RI)" <>
Date: Thu, 5 Jul 2018 22:15:51 -0400
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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)

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