[R-390] Slippery stuff

[Charles Steinmetz]

Bob wrote:

>The Ethanol is a sticking point here.  Trying to locate this crucial 
>part of this method of lubrication, has been frustrating to say the least!
>
>Is there anything else that this powder can be mixed with?

Any of the usual alcohols should be fine -- the only difference is 
whether one or another of them would attack what you want to put the 
WS2 on.  Ethanol is the gentlest alcohol in this regard.  However, 
since you will almost certainly be using it on metal, attack is 
unlikely as long as there is no more than a minimal amount of water 
in the solvent.  In this regard, note that whatever high 
concentration of ethanol you start with, it will become an azeotrope 
of about 95% alcohol and 5% water very shortly, because the 
hydroscopic nature of the alcohol will pull water out of the 
atmosphere.  This will be true even in a sealed container, because 
there is always some atmospheric exchange.  I once worked in a lab 
where we used absolute ethanol, and the precautions necessary to keep 
it that way are extraordinary.

Common denatured alcohol (hardware store "solvent alcohol") is 
generally 95% ethanol with about 5% methanol mixed in.  Isopropyl 
alcohol is available in 99%, although the drugstore variety has 
settled on 91% over the last 20 years.  Honestly, I don't see any 
reason why 91% isopropyl wouldn't be perfectly fine.  If you put it 
somewhere you worry that the water will not evaporate out, heat it 
with a hair dryer for ten minutes.

Best regards,

Charles