Also, a thought from the electrician side of the fence. I had to learn
this because my brother-in-law bought a 60's vintage aluminum wired
house and asked for some help with its wiring.
When working with aluminum wiring, especially old stuff, it's been found
that it's best to have the scotchbrite pad being used to clean the wires
to be filled with Noalox.
The understanding is that aluminum almost immediately skins over with
oxide after being dry abrasively cleaned. Having the Noalox in the pad
puts down a film that protects the cleaned surface from re-oxidation.
Aluminum oxide is an insulator.
They found this out when investigating failed junctions made with wire
nuts that had proven to be faulty and had caused house fires. What they
discovered was that the only path between the twisted wires of the
junction was through the metal threading of wirenut itself, which is not
designed to carry current. It was making the circuit because the
wirenut's threads had cut through the oxide completing the connection
between the twisted together oxide insulated wires.
Stan
On 5/22/2018 9:05 PM, Bob Shohet, KQ2M wrote:
Hi Rich,
You want just enough of a thin film to provide lubrication and to prevent
corrosion/oxidation – no more lest you partially or completely insulate one
section of the telescoping tubing from the other. (I put too much one time and had to
take the antenna down to wipe it off because the swr and bandwidth was way off!)
NOW what I do is as follows:
I put on a pair of large nitrile gloves ($20 for a box of 400 at Costco) and put about
1/2” of Noalox on one glove and then grasp the tubing and smear it on with my hand in
a circular motion up and down a few times for about 3’ on the element. (I know it
reads like something obscene but it is not. LOL!)
Then I take a paper towel and gently grasp the tubing and wipe off and go up
and down and the paper towel takes most of it off and leaves a thin continuous
film all the way around the element.
Since I adopted that method, I have never put too much on nor have I had a
problem taking apart an element years later.
The best part is that you do not get any goop on your hands or hands – clean up
is really easy - you just throw the gloves and the paper towels in the garbage and you
are done!
73
Bob KQ2M
From: Richard Smith
Sent: Tuesday, May 22, 2018 8:04 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Amount of "Goop" to use in Telescoping Aluminum Tubing
Connections?
"Goop" = Penetrox, Noalox, Jet-Lube SS-30, or other
A while back, there was a good discussion on this reflector of which goop is recommended for telescoping
aluminum tubing connections in antennas. My question here is not intended to recap all of the "Which
Goop is Better" points, but rather to ask how much goop to use. Over the years, I have heard
recommendations from "very minimal" to "lots".
I would be interested in recommendations from this very experienced group. The
trade-offs in my mind are:
Very minimal amount: Pros: Allows the aluminum to aluminum contact to provide
the electrical connection. The goop provides some lubrication, maybe some
corrosion protection. Cons: Not enough
corrosion protection, not much help in separating telescoping parts when
desired years later.
Lots of Goop: Pros: Assists in making a good electrical connection,
provides more corrosion protection, easier to separate parts when desired years
later
Cons: Maybe too much lubrication, harder to
get hose clamps tight enough to prevent unwanted slippage.
Maybe this is very basic, but I am interested in your comments.
Thanks in advance,
73, Rich, N6KT
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