----- Original Message -----
From: "Jack - K4WSB" <K4WSB@arrl.net>
To: <K7LXC@aol.com>; <towertalk@contesting.com>; <mel@melwhitten.com>
Sent: Thursday, November 09, 2006 8:50 AM
Subject: Re: [TowerTalk] Restoring Beam Antennas
>I had a ham fried who was the radio office on a sulphur ship. Over
> the years he tried everything to attempt to protect his
> antennas. Needless to say, between the salt & sulphur fumes nothing
> worked.
> On one occasion he sprayed Krylon and found that once the paint
> cracked it allowed moisture to creep under the paint and caused more
> corrosion.
>
If you are in that kind of environment I'd use the same stuff they use on
the lower sides of cars called "chip guard". I'm not sure what it's made
of, but it's a some what flexible plastic. It would add noticeable weight,
but in a hostile environment might be worth any of the drawbacks.
> This was more than a few years back so my question is: are the
> current acrylics more flexible and less prone to cracking? Once it
> does crack will it not cause for more problems?
Acryllics are prone to cracking, but some acrylics are more prone to do so
than others. One alternative that is "tough" but even more expensive than
tough is the two part Cyanolics. You can get clear (same stuff made for
clear coating paint jobs on cars and airplanes. Being a Cyanolic it requires
supplied breathing air, not just a mask so it can be nasty stuff to work
with.Generally they use a phosphate etch and either use a chromate primer,
or alodyne alodine? treatment on the Aluminum to corrosion proof it and prep
it for paint. Properly done the Alodine gives a shiny gold finish. Needless
to say this process takes lots and lots of washing to remove all traces of
the etch and the alodine solution. That gold color is very thin and can be
rubbed off with a bit of work.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> At 08:37 AM 11/9/2006, K7LXC@aol.com wrote:
>>
>>In a message dated 11/3/2006 5:46:19 A.M. Pacific Standard Time,
>>towertalk-request@contesting.com writes:
>>
>> > I use Krylon #1301 Crystal Clear Gloss acrylic, available most
>>hardware/paint stores.
>>Drys quick about 50 deg F.
>>_http://www.hardwareworld.com/Sp-Crystal-Clear-Acrylic-pC443NR.aspx_
>>(http://www.hardwareworld.com/Sp-Crystal-Clear-Acrylic-pC443NR.aspx)
>>
>> Some professional installers use this as the final coating on a coax
>>connector joint over the final wrap of tape. It's better than
>>ScotchKote since
>>ScotchKote is meant for buried applications and does dry up and
>>blow away when
>>used in normal tower/cable applications.
>>
>> I'd be careful with the spray acrylic around some antenna
>> insulators. I
>>had a customer spray his new KT34XA with a coating of Krylon acrylic and
>>the
>>danged stuff melted and cracked the Lexan element insulators.
>
> Jack Hartley
> K4WSB / VP2MSB
> ARRL - QCWA - OOTC
> DXCC Honor Roll
>
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