[TowerTalk] Question regarding electrical connectivity of frozen telescoping aluminum tubing

[Don]

Been following this thread with interest. I live about 400 yards from 
the ocean on the central coast of OR.

Last summer I did some repair work on the 1st DE 5M traps of my old 
(really old) TH7DX. I was able to wrestle the traps with outer attached 
end elements off, but it was difficult. After seeing that all the trap 
coil screws were corroded lumps of rust I cleaned the traps up, replaced 
the screws with SS and a liberal coating of Penetrox and reassembled 
what I had.

While I suspected that all of the trap screws were suffering the same 
rust fate, I did not have the time to pull them , but did attempt to 
pull just one of the 10M traps on the 1st DE. I found there was no way I 
was going to arm wrestle or use a pipe strap to get the tubing to tubing 
apart on the trap tube to element tube joint. Was sure I'd face the same 
issue with all the other tubing to tubing joints.

This summer I'd like to go through and clean up all the traps and 
elements but I know what I'm surely facing in attempting to pull all the 
tubing pieces apart. When originally assembled back so many decades ago 
I used the grey or silver colored 'goop' that was supplied by HyGain. 
Have no idea what it was but dutifully followed the instructions. It 
seems to have acted more like glue.

So, what is the preferred/best method to get tubing to tubing that is 
seemingly hard stuck separated if they just won't come apart with 
reasonable hand or strap force? Do I use a propane torch and heat the 
tubing? Or? (And just what was the 'goop' HyGain originally supplied?)

Don W7WLL

On 7/18/2019 12:27 PM, john at kk9a.com wrote:
> I agree on both counts. Scotch-brite pads work well for cleaning up 
> old tubing. I have built many large homebrew Yagi's using old 6061 
> aluminum tubing.  Steel wool can leave metal partials embedded into 
> the aluminum that can corrode, Scotch-brite has no steel. After owning 
> a station in Aruba and seeing the effects of severe corrosion, I try 
> to avoid unnecessary dissimilar metal contact. Aluminum and copper are 
> not close together on the galvanic table. I know that some of the big 
> multi contest stations are using copper anti-seize on their antennas 
> but I use Penetrox.
>
> John KK9A
>
>
>
> Joe Subich, W4TV wrote:
>
>
> I would not use *either* steel wool or copper bearing anti-seize. Both
> copper and steel will set up electrolysis with the aluminum that will
> cause future conductivity and mechanical problems.
>
> Stick with thee scotch pad and an anti-seize made specifically for
> aluminum.
>
> 73,
>
>     ... Joe, W4TV
>
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