[TowerTalk] STAINLESS STEEL BOLT AND ALUMINIUM ROTATOR

[Jim Thomson]

Date: Tue, 15 Nov 2011 09:25:21 +0000
From: Ian White GM3SEK <gm3sek at ifwtech.co.uk>
Subject: Re: [TowerTalk] STAINLESS STEEL BOLT AND ALUMINIUM ROTATOR
CASINGPROBLEM

>On 11/14/2011 1:49 PM, john at kk9a.com wrote:
>> There is tremendous corrosion to aluminum when in contact with stainless
>> steel and salt spray.  As much as I like stainless steel hardware, I would
>> still avoid using it in aluminum threads if you're in a corrosive
>> environment.
>>
>> John P40A
>>
>
>I had heard the same thing.  Stainless seems OK in aluminum under
>ordinary conditions, but the Navy has a "salt spray" test that
>this combination fails.
>
>Rick N6RK

One solution is to fix stainless studs into the threaded holes, using a 
permanent thread-locking compound. The studs pass clear through the 
holes in the lower part of the rotator shell and can be secured from 
below by stainless nyloc nuts, which can always be easily removed.

As well as fixing the studs into the threaded holes, the locking 
compound permanently seals the aluminum/stainless thread interface and 
protects it from any further corrosion.

One final point: this modification is easiest, and works the best, if 
it's done *before* the aluminum threads have become seriously damaged. 
Otherwise you're into re-threading the holes to a larger size, which 
then brings further problems about clearances.


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek

###  use  PB blaster, and soak it  for 24 hrs, then use an impact wrench,
or an air ratchet.  Electric impact wrench's have even way more TQ vs
the air type.  [ I have both]

##  Loctite  makes this goop called... "never seize".   Comes in 2 x grades,
'silver'  and 'marine grade.'  They are both silver colour. I slop that stuff on all my stainless hardware. 
I also use it on all non stainless hardware as well.  You slop in on both the male and mating female
threads.  You will never have any problems getting it apart after that.  IF using SS hardware,
check the threads..1ST !!    All you need is one ding in a male thread, and you will have a 
helluva time with galling, ESP if  SS  nylock nuts are used.   Either hand pick them when you buy
them, or... run good and bad threads through a die 1st.   [ tap + die set]. This will clean up any threads. 
Noalox, etc, will eventually dry out, I only use that on yagi els, and never SS hardware. 

Later... Jim   VE7RF