[Elecraft] OT aluminum oxide

[Lew Phelps K6LMP]

One possible solution would be to soak the "stuck" joints a solution of sodium hydroxide (lye, as in drain cleaner). There's a web site that discusses the chemical reaction and the ability of lye to dissolve existing layers of aluminum oxide. See:

http://www2.uni-siegen.de/~pci/versuche/english/v44-10.html

The site says, in part:

A layer of aluminum oxide previously formed by passive corrosion is dissolved by the addition of sodium hydroxide. For this reason, the reaction takes place at the beginning relatively slowly:

Al2O3 + 2 NaOH + 3 H2O ––––> 2 Na(+) + 2 [Al(OH)4](-)

I have never tried this myself, so I would want to test it on some scrap aluminum or a no-longer-used antenna, to be sure the lye doesn't eat away the pure metal as well as the aluminum oxide.  

But it might be worth a try. Use protective goggles and gloves, etc. any time you're working with lye. 

Lew K6LMP


On Oct 19, 2010, at 11:37 AM, WILLIS COOKE wrote:

> If anyone knows the answer to this one, I say it is not off topic.  It is not 
> Elecraft, but it sure is ham radio.  I have had some mixed results from heating 
> the outer tube with a propane torch, but it is by no means fool proof.  The only 
> fool proof method that I know is to treat the joint before assembly and take it 
> apart every couple of years.  I use to use grease mixed with graphite powder and 
> that worked very well, but our environmental friends have made it so that 
> finding graphite powder is difficult to impossible.  There are various products 
> available now at high prices to do the job.  After the fact is really tough and 
> sometimes a hack saw and a splice may be in order.  These are not great answers, 
> but they are the best I can do after 50 years of fighting the problem.
>  Willis 'Cookie' Cooke 
> K5EWJ 
>