[Elecraft] KX3 4 knobs and sea spray/salt corrosion

[Edward R Cole]

Dom,

I retired in 2009 from a 15-year job as radio tech for a company that 
had seven ships operating on salt-water (Cook Inlet Alaska) and salt 
corrosion can be a struggle to defeat.  Most of the electronics I 
maintained were marine equipment so designed with salt-air/spray 
exposure anticipated (use of plastic cases and gaskets on the case, 
stainless connectors with small rubber boots for covering antenna and 
power connectors.  But we also installed VHF business radios which 
were not designed for "on water" use.

I will say most were enclosed in a pilot house or cabin so direct 
spray was extremely rare.  But the boats were stored on a pier 
adjacent to the water year-round so constantly exposed to salt 
air.  Any exposed metal would eventually show "green-blue" copper 
corrosion.  The dc connections were made underside of cabinets or on 
the inside roof of cabins and not sealed.  This could not be 
conveniently sealed with "goop" that is made to paint such 
connections as they needed to be accessible for quick change out (for 
safety reasons).

Are you operating the radio on-board the vessel?  If not, why not 
enclose the radio in a large plastic zip-lock bag to protect it from 
exposure?  Likewise on the shore only expose it when actually in-use 
and keep in sealed inside a bag,otherwise.

You still will have to do regular maintenance to clean the exterior 
surface, but this may reduce the exposure of the interior of the 
KX3.  Silicone sealant is effective for retarding lots of this in 
some applications.  Wrapping cables and connectors in tape works very 
well (I had coax connectors last over five years in our service as 
long as not unsealed).

I'll be interested to see what others may offer.

73, Ed - KL7UW
-----------------------------------------------
Date: Sun, 14 Jul 2013 16:33:45 +0100
From: Dominic Baines <dominic.baines at ntlworld.com>
To: elecraft at mailman.qth.net
Subject: [Elecraft] KX3 4 knobs and sea spray/salt corrosion
Message-ID: <51E2C4D9.8020907 at ntlworld.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi,

In the last year I have operated a few times /P from the beach often
with sea spray and recently twice on long ferry crossings of the North
Sea (return operating was cut short though) and out on deck most things
end up with a mist or film of sea spray on them and you will see the
small white spots of salt when the water evaporates. I have noted at
least two of the 4 knurled knobs on my KX3 are showing signs of
corrosion and were becoming difficult to turn. I have cleaned the nut
threads (both sides) and applied a very little copper grease to them I
also washed the whole of the KX3 inside and out (part disassemble
needed) using cotton buds and isopropal alcohol where any salt effects
were obvious. The front bezel screws had kept 99.99% out from the
display but I have had to remove that and clean it up a bit. I might put
back with a fine bead of silicon sealant.

I have added a small copper braid flying lead between the two parts of
the case and covered it with 'liquid rubber'.

The clam shell style unfortunately is not great if you operate in these
environments as sand/salt does get in no matter how hard you try to
protect it.

I do not immerse the radio in the sea but after a couple of weeks in
this environment you will notice the effect. In the meantime antennas
have had to have connectors remade etc. so it is not really a surprise.

Has anyone got an alternative to these knurled knobs that are a little
bigger as it is very difficult to open the case wearing gloves? (you
only need to if you are using the AA batteries which I tend not to if
that wet) I had thought about swapping them for Ali versions or cutting
slots in them for a screw driver. Anything like those lay flat butterfly
nuts/ knobs you used to find on old military kit might suit better.

In definitely wet (i.e. raining) conditions the KX3 is used inside a
tough see through plastic box (lock'n'lock) with leads passed through it
with bathroom silicon sealant. I used to do this with my FT817 as well.
Costs ?5 from supermarket.

I wish the KX3 had a lock frequency function which would be useful when
I have to do this, why is this still missing?

72

Dom
M1KTA


73, Ed - KL7UW
http://www.kl7uw.com
dubususa at gmail.com
"Kits made by KL7UW"