[TowerTalk] Lubricating air variable capacitors

[Jim Lux]

At 04:23 PM 10/2/2005, Tod - ID wrote:
>Jim:
>
> >
> > WD-40 is not a lubricant.
> >
>
>As I understand it WD-40 is very similar to a light weight diesel fuel. I am
>sure it is a petroleum based product. I would have expected it to have some
>lubricating properties . Could you or someone on this list expand on this to
>give me an idea of the WD-40 limitations.


Well..I may have spoken a bit strongly. It IS a lubricant, after a fashion. 
It's slippery, and the mfr advertises it as lubricating.  However, it seems 
to be quite volatile. That is, spray WD40 on something and after a month or 
so, it doesn't seem to have much of a coating on it. Probably just enough 
to prevent corrosion. I'm not sure which property I'm talking about.. 
perhaps surface tension, or goopyness, or clingyness.  It also is very 
effective at dissolving oil and grease out of a bearing.

It's probably fine as a lubricant if regularly reapplied.  In a long 
duration application (like a bushing in a capacitor), I think you'd want 
something with a lower vapor pressure, longer chains, or whatever it is 
that makes oil stay in a bearing.

Here's a usenet post about it:
http://yarchive.net/chem/wd40.html