[TowerTalk] Force 12 hardware and aluminum treatment for corrosion resistance

[Patrick Greenlee]

Sea going vessels with aluminum superstructures and welded-on-deck vertical 
aluminum channels (think channel iron but aluminum instead) for mounting 
tuners and or antennas with stainless steel fasteners connecting tinned 
copper crimp terminals when exposed to the environment for a few months show 
the following:

1.  Corrosion/pitting of the aluminum channel near (within 1/2 inch or so) 
the drilled hole where the stainless fasteners secure the terminals.
2.   Corrosion of the ID of the hole with the stainless machine screw 
through it.
3.  Corrosion of the exposed coax braid. Braid turns to mush totally 
disintegrating.

Well du-uh... given the dissimilar metals in contact with each other and the 
salt water for electrolyte you have a galvanic cell which eats away at the 
less noble of the two galvanic cell plates, especially without the 
protection of a product such as coax seal.

So the marine radio equipment installer whose prime motivation is to make 
things look neat as he finishes the job, uses his "UNIVERSAL FIX" which is 
to apply some silicone rubber (RTV - room temperature vulcanizing)  to all 
metal near or touching any of his handiwork.  This slows the corrosive 
destruction by several days or maybe a few weeks or if luck id with you, 
several months..

I have seen coax cables terminated with PL-259 (properly installed) for 
connecting to a SO-259 female UHF connector (bulkhead mount style) with 
ample Silicone rubber over everything but with the mounting flange of the 
bulkhead mounted connector being eaten away by galvanic corrosion due to 
dissimilar metals in contact with an electrolyte present. The mounting holes 
were essentially gone from the connector and the holes in the aluminum 
substrate (channel) were eaten out considerably oversized.

If you install antennas, feedlines, etc. in conditions including significant 
quantities of airborne salt then you may experience some of the above 
undesired results.

Perhaps some of the more experienced and knowledgeable members of this 
august gathering can set forth a prescriptive methodology for preventing the 
above mentioned deleterious effects.

Patrick AF5CK


-----Original Message----- 
From: Jon Pearl - W4ABC
Sent: Tuesday, September 10, 2013 9:50 AM
To: john at kk9a.com
Cc: towertalk at contesting.com ; jwfisher at alumni.princeton.edu
Subject: Re: [TowerTalk] Force 12 hardware and aluminum treatment for 
corrosion resistance


Hi Jim,

For the past few years I've used a product called Never-Seez Regular
Grade with great success on all of my outdoors fasteners. I'm surrounded
by water. I've got the Gulf of Mexico to the west and Tampa Bay to the
east.

REGULAR GRADE

The original anti-seize compound and extreme pressure lubricant
formulated with copper, graphite, aluminum and other ingredients to
protect metal parts against rust, corrosion and seizure up to 1800:F.
Specified by BMW, Mercedes, GE D6Y28A1, Garrett Engine Division PCS5724,
Pratt & Whitney PWA 36053-2 and tested to MIL-A-907.

http://www.bostik-us.com/market-products/product-assembly/mro/products/#regulargr
http://www.bostik-us.com/sites/default/files/NSRegular.pdf

It's available online at Amazon, etc., for less than $15 U.S. per 8 oz
brush top container.


73,


Jon Pearl - W4ABC
www.w4abc.com



On 9/10/2013 9:19 AM, john at kk9a.com wrote:
> What an awesome QTH! I also use stainless steel hardware however I have
> seen severe salt spray corrosion to aluminum where the S.S. is in contact.
>   What do you do to protect the tower system from corrosion?
>
> John KK9A
>
>
> To: towertalk <towertalk at contesting.com>
> Subject: [TowerTalk] Force 12 hardware and aluminum treatment for
> corrosion resistance
> From: Jim and Hannelore Fisher <jwfisher at alumni.princeton.edu>
> Date: Tue, 10 Sep 2013 12:36:46 +0000
>
> I live in a salt-air environment and have replaced just about all U-bolts 
> and
> other such hardware with stainless steel. Be sure to coat bolts with an
> appropriate compound before installing nuts--if you are not familiar with
> this,
> ask your SS supplier.
>
> Also, per advice from F12 many years ago, I assembled elements and then
> painted
> them with XIM400, which has protected them nicely. At some points, I have 
> had
> over 50 F12 elements up at the edge of a cliff with saltwater to the 
> horizon
> and little fluffy balls of salty foam flying up and over.
>
> 73,
>
> Jim, VE1JF
>

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