[Antennas] Penetrox, Noalox, Alumatrox

[Barry L. Ornitz]

Eric Lemmon, WB6FLY, noted:

> 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).

Actually the Penetrox A-13 is in a polyalkalene glycol base
which is water soluble and is not a silicone at all.
However a second source noted it also contains castor oil.
It is for use around polyolefin insulation (polyethylene,
polypropylene) which might be attacked by the petroleum
grease in regular Penetrox.  The Penetrox E also contains
graphite and is sold specifically as an anti-seize.

> 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.

Jet-Lube makes many different anti-seize compounds
including one that has nickel powder.  Most contain more
than just a lubricating grease and metal powder though.
Unfortunately most of the MSDS information I found on Jet-
Lube products lists the ingredients as proprietary.  In my
experience, companies that do this usually sell their
products with the aid of considerable hype (such as WD-40
who once listed the ingredients in their MSDS).  But as I
have no experience with Jet-Lube, I'll rely on your
judgement here.

While Penetrox and Noalox do provide considerable anti-
galling protection, they were designed specifically for
improvements in electrical in electrical contact between
aluminum joints.  From what I have seen, they use zinc
particles that have sharper edges and points than the
typical fumed zinc dust often found in anti-seize
compounds.  This provides for better piercing of the
aluminum oxide layers  Naturally the smoother finish on the
aluminum to start with, the better these compounds work.
So for antenna use, be sure and polish the aluminum pieces
first; I often use Scotch-Brite pads for this.  Then apply
the Penetrox/Noalox/etc. before assembling.

> 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.

Alternately many steel and copper terminal lugs are zinc
plated for the same reason.  Copper to aluminum couples
used outdoors are probably the most difficult dissimilar
metal corrosion problem I have seen.

> 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.

Based on the water solubility of the glycol in the binder
of A-13, I would suggest the regular Penetrox A instead.
Is there much difference in price?

        73,  Barry     WA4VZQ     ornitz@tricon.net