[Antennas] Penetrox, Noalox, Alumatrox

2002年8月28日 18:27:00 -0700

Barry,
You presented an excellent tutorial on the basic uses of Penetrox and
similar anti-oxidant compounds. I'd like to add a few points:
1. The trademark "Penetrox" covers a family of compounds, some of which
contain zinc granules in a petroleum base (Penetrox-A) or in a silicone
base (Penetrox-A13), and at least one that contains only copper granules
(Penetrox-E).
2. I disagree with the statement that such compounds are not really
designed to be anti-galling agents. In fact, the Aluma-Kote (zinc) and
Kopr-Kote (copper) compounds sold by Thomas & Betts for the same
purposes as Penetrox , et al, is actually Jet-Lube anti-seize compound
with a different label! I know this to be true, because the MSDS sheet
lists Jet-Lube as the manufacturer, and the formulation thereon is
identical to the MSDS listing for Jet-Lube aviation-grade anti-seize
compound.
3. On the issue of using a zinc-containing compound on
aluminum-to-copper connections, I have never had a problem with this-
but then, I am very careful to clean the contact surfaces well and seal
the joint against moisture intrusion. I will acknowledge that most
large aluminum terminal lugs that are UL-listed for copper conductors
(such as those in a typical electrical service panel) have a thin tin
plating to separate the aluminum from the copper.
I always assemble aluminum antenna sections with Penetrox-A13, and have
never had any of the erratic behavior attributed to noisy or
"electrically loose" elements. I also use this stuff on galvanized
steel tower joints, and it ensures that they will come apart easily
years later.
73, Eric Lemmon WB6FLY
"Barry L. Ornitz" wrote:
> Penetrox, Noalox, etc. are materials designed to aid in
> aluminum-to-aluminum electrical connections as an
> antioxidant. They are not really designed to be primarily
> a lubricating grease or anti-galling agent. However their
> makeup does contain lubricant which does aid in the
> assembly and disassembly of antennas.
>> These materials are all made of fine zinc particles
> dispersed in a lubricating binder. The zinc particles are
> hard and have irregular rough surfaces. When two pieces of
> aluminum are clamped together with this material in
> between, the zinc particles cut through the surface oxide
> layers on the aluminum and provide better electrical
> contact. The binder, which is generally a light organic
> material similar to thin petroleum jelly, tends to prevent
> oxygen from getting to the contact points. Sometimes an
> aluminum soap such as aluminum stearate is added to the
> binder.
>> Zinc is an excellent material for use here. Not only is it
> harder than aluminum, a property needed to "bite through"
> the oxide layers, zinc is also compatible with aluminum
> from a galvanic corrosion standpoint.
>> The Penetrox and Noalox I have used are not what I would
> consider super messy to use. They are usually a gray,
> somewhat gritty, grease. They are quite different from the
> black graphite or molybdenum disilicide containing
> automotive greases used to prevent seizing and galling of
> high temperature bolts. These automotive materials are not
> really suitable for the aluminum-to-aluminum application
> either. [For high temperature stainless joints, a silver
> containing grease is used to prevent galling.]
>> While you often see Penetrox suggested for aluminum-to-
> copper joints, it no longer provides the proper galvanic
> compatibility here. It is probably better than nothing but
> copper-to-aluminum joints will always create galvanic
> corrosion problems.
>> I generally buy Penetrox of Noalox at industrial electrical
> supply stores. I know Home Depot often carries one or the
> other.
>> Dr. Barry L. Ornitz WA4VZQ [email protected]
>> - - -
>> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
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