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[TowerTalk] Rohn joint bolts

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Subject: [TowerTalk] Rohn joint bolts
From: w7ni@teleport.com (Stan Griffiths)
Date: Thu, 15 May 1997 02:40:10 -0700 (PDT)
>Roderick M. Fitz-Randolph wrote:
>
>> I suppose it inevitably comes down to the decision of each individual that
>> installs a tower but after seeing the rusted through and nearly rusted
>> through bolts supplied by Rohn for installation of those towers I've
>> "de-installed", I'll put my trust and belief in those stainless bolts and
>> nylon-inserted lock nuts!!!
>> 
>> 73, Rod  W5HVV
>
>I have done the same with Heights aluminum towers for years.  I put the
>first one up using the plated hardware.  Ever since, stainless only! 
>When one of these towers fails because of stainless steel hardware, I
>will rethink my decision, but not before....29 years and counting.
>
>73, Ken K4XL
>grimm@alison.sbc.edu

Here is something to think about:  In 1971, I acquired a very used 3 element
Telrex 20 meter beam.  It was up and I took it and two other 3 element 10
and 15 meter monobanders down and replaced them with a new tribander for
another ham.  He gave me the Telrex 3 el 20 for my trouble.  In any case,
the hardware with the Telrex was stainless bolts, nuts, and washers holding
a couple of U-shaped straps to an aluminum plate that served as a
boom-to-mast plate.  The stainless hardware was nearly perfect, but the
aluminum was turning to white powder.  I consulted a table of metals and
found that aluminum and steel are quite far apart on the "galvanic action"
scale.  Apparently, all the detioration takes place on the aluminum.  Zinc,
on the other hand, is very close to aluminum in the same chart, and this
would tend to suggest that galvanized hardware will be much less likely to
cause the aluminum to turn to white powder.

It would be interesting to hear a few other thoughts on this . . .

Stan  w7ni@teleport.com


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