Restoring a Hy-Gain Yagi...
 

I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware? Which would react least over time with
the aluminum? Also, I remember many years ago there is an electrical
joint compound stuff for using between the tubing sleeves - can anyone
please give me some brand names of this stuff?

Any other ideas appreciated....

Larry VE7EA

Restoring a Hy-Gain Yagi...
 

Larry,

I use "Ox-Gard", available from the local "Do-It Center" hardware store
outlet. Preserves overlap joints on aluminum tubing and makes them easy to
adjust and disassemble after years outdoors.

Works fine for radio waves, but does not conduct DC. Found this out the hard
way in an application where I was passing RF alongside some DC signaling
information. The RF got through just fine, the DC not so much.

-larry
K8UT
"lagagnon" wrote in message
...
I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware? Which would react least over time with
the aluminum? Also, I remember many years ago there is an electrical
joint compound stuff for using between the tubing sleeves - can anyone
please give me some brand names of this stuff?

Any other ideas appreciated....

Larry VE7EA

Restoring a Hy-Gain Yagi...
 

On Apr 28, 3:43*pm, lagagnon wrote:
I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware? Which would react least over time with
the aluminum? Also, I remember many years ago there is an electrical
joint compound stuff for using between the tubing sleeves - can anyone
please give me some brand names of this stuff?

Any other ideas appreciated....

Larry VE7EA

I would stay away from the steel wool. Bits of it will imbed in the Al
and rust.

Jimmie

Restoring a Hy-Gain Yagi...
 

lagagnon wrote:
I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing,

Avoid steel wool. Inevitably, it will leave little iron/steel fibers
behind, which will rust/corrode/react with the aluminum.

Use synthetic scrubbies (3M ScotchBrite) instead.


I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware? Which would react least over time with
the aluminum? Also, I remember many years ago there is an electrical
joint compound stuff for using between the tubing sleeves - can anyone
please give me some brand names of this stuff?

Any other ideas appreciated....

Larry VE7EA

Restoring a Hy-Gain Yagi...
 

On Tue, 28 Apr 2009 12:43:59 -0700 (PDT), lagagnon
wrote:

I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware? Which would react least over time with
the aluminum? Also, I remember many years ago there is an electrical
joint compound stuff for using between the tubing sleeves - can anyone
please give me some brand names of this stuff?

Any other ideas appreciated....

Larry VE7EA

I just called Bencher/Butternut about my aluminun vertical and they
suggested NOT using steel wool for cleaning because the residue
of the steel wool rusts very easily. I know this is true from my boat
where we generally use bronze wool to avoid rust. The steel wool sheds
(and I know this from hard experience) as a bear to clean out of
stuff, such as the deck of my boat. The Butternut guy suggest that
rather than steel wool use either emery paper or a Scotchbright pad as
they do not leave residue. Butternut also has a conductive grease that
they provide with their antennas to keep the metal to metal joints
conductive. Steel wool residue can also cause bimetalic corrosion with
aluminum.

Most assuredly use stainless steel fitting and screws. Ordinary
screws/nuts will rust very rabidly. Any boat owner knows that
many so-called compression clamps, allegedly in stainless, do not have
stainless bolts to tighten them. Most of us take a magnet to the
boating store to ensure we got the right things. BTW a boating store
is generally a pretty good place to get stainless steel hardware. They
know that a boat owner will scream bloody murder and besmirch their
reputation if they sell anything but the top quality stuff. We ran one
boating store out of town for selling shoddy stuff.

I'm embarking on exactly the same rebuild on my Butternut vertical so
I just talked to the factory specialist on this very subject just last
week. My spare parts just arrived yesterday. I'm rebuilding because
after 25 years, the wind flexed the tube that mount the antenna, a
vertical, into the ground. I guess that is not too bad service for
this antenna.

Jon Teske, W3JT
Maryland

Restoring a Hy-Gain Yagi...
 

JIMMIE wrote in news:9b6a811c-4f7a-4686-a503-
:

....
I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless

If you brush aluminium with a material, there is a tendency for the
material to become embedded in the surface.

Stainless steel is widely used to brush aluminium clean before welding, and
with minimum degradation. I would not use steel wool. Non metallic
scrubbers may embed non-conductive material in the surface, frustrating low
resistance connection between clamped surfaces.

I have found the little Dremel #530 stainless wheel brush handy for scratch
cleaning the inside of mating tubes, although limited in reach. I haven't
tried, but the flexible shaft adapter might give good reach into larger
diameter tubes. For the outside, I just use a stainless scratch brush.

Owen

Restoring a Hy-Gain Yagi...
 

I figure steel wool would work fine for the aluminum tubing,

I've read that it is *not* a good idea to use steel wool to clean up
aluminum, especially if it's going to be exposed to the weather.
There's a tendency for tiny bits of the steel to get caught in the
aluminum... it'll rust.

I'd suggest using a 3M (or generic equivalent) green abrasive
scrubbing pad. These pads are rough enough to remove oxidation from
copper PC board material, so I imagine they'll shine up aluminum just
as well, but they won't leave rustable material behind.

I know
how to test the traps, but I am wondering whether to use stainless
steel or galvanized hardware?

I believe that you can get some amount of electrolysis if galvanized
metal and aluminum are in contact, especially if the aluminum is not
well-anodized or if there is electrolyte around (e.g. if your area is
subject to salt spray). Some people in the boating trade claim "no
problem", others state that you should never use zinc-galvanized and
aluminum together.

Stainless-steel-and-aluminum seems to be the preferred combination.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Restoring a Hy-Gain Yagi...
 

Owen Duffy wrote in
:

JIMMIE wrote in news:9b6a811c-4f7a-4686-a503-
:

...
I figure steel wool would work fine for the aluminum tubing, I know
how to test the traps, but I am wondering whether to use stainless

....
Apologies, I mis-quoted there, the text was by lagagnon
.

Owen

Restoring a Hy-Gain Yagi...
 

Dave Platt wrote:
I figure steel wool would work fine for the aluminum tubing,

I've read that it is *not* a good idea to use steel wool to clean up
aluminum, especially if it's going to be exposed to the weather.
There's a tendency for tiny bits of the steel to get caught in the
aluminum... it'll rust.

I'd suggest using a 3M (or generic equivalent) green abrasive
scrubbing pad. These pads are rough enough to remove oxidation from
copper PC board material, so I imagine they'll shine up aluminum just
as well, but they won't leave rustable material behind.


3M pads and Bon Ami cleaner works well.

And clean aluminum has better gain. One of my 432 antennas tested at
Central States gained .4dB between very dirty oxidized elements and
cleaned elements.

tom
K0TAR

Restoring a Hy-Gain Yagi...
 

(Dave Platt) wrote in :

I figure steel wool would work fine for the aluminum tubing,

I've read that it is *not* a good idea to use steel wool to clean up
aluminum, especially if it's going to be exposed to the weather.
There's a tendency for tiny bits of the steel to get caught in the
aluminum... it'll rust.

I'd suggest using a 3M (or generic equivalent) green abrasive
scrubbing pad. These pads are rough enough to remove oxidation from
copper PC board material, so I imagine they'll shine up aluminum just
as well, but they won't leave rustable material behind.

Neverdull is far better to use.

http://www.nevrdull.com/