[TowerTalk] Cleaning Aluminum Eelements

K7GCO@aol.com K7GCO@aol.com
Mon, 20 Mar 2000 16:16:29 EST


In a message dated 20.03.00 08:17:14 Pacific Standard Time, K7LXC@aol.com 
writes:

<< In a message dated 03/20/2000 7:00:52 AM Pacific Standard Time, 
 DAVED@ctilidar.com writes:
 
 > Cleaning the outside is easy. How do you clean the inside of those small
 >  diameter elements?
 >  
       Why would you need to do that? RF observes the skin effect and only 
 travels on the outside of the conductor. 
 
 Cheers,   Steve   K7LXC
 Tower Tech
  >>
Steve: There are antennas where they weren't coated inside the joint or just 
tubing sitting out side that Aluminum Oxide can build up and actually prevent 
insertion or very often removal.  There is only about .006" clearance when 
new (less with double coating) and always gets less unless regularly cleaned 
and or coated inside and frozen joints do occur.  I've had tubing with 
Aluminum Oxide build up that still allowed insertion--barely.  It galled and 
I never got it out.  That's a good reason to clean tubing inside.   

The Brass or SS Brushes are great for cleaning inside the tubing but don't go 
deep enough.  Make a 1' extension.  Inside cleaning in not for conductivity 
except for about .005-.01", it's for removability.  That's even why grease 
with zinc in it serves no useful purpose to punch through the Aluminum Oxide 
as you stated--beyond the very thin ring of connection at the diameter 
increase.  Conductivity is needed only there and both sides of SS hose 
clamps.  Pick out those small particles of zinc you like so well and make a 
thin circle of zinc right at the joint connection.

No diameter increase and decrease is the goal inside the joint so it can be 
taken apart--to renew the thin ring of ZINC (aluminum particles are better) 
conductivity some time later which is a good idea.

The savior without any of these monumental problems is called the quad--one 
soldered joint per element with copper wire.  Or just clean used or even new 
Aluminum tubing properly, coat it inside and out with a grease with aluminum 
particles, clamp it tight around the "thin ring of conductivity" at the 
diameter change (I like 360 degrees) and that's all you can do.  It's 
subjected to weathering and it's a good idea to refresh it once in a while.  
You have to be able to get it apart to do that also.  K7GCO

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