On Sat, 19 Sep 2015 12:23:50 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Ed Huntress fired this volley in
:

The"soap" used in greases is metallic soap. It is not what we
generally think of as "soap" and it doesn't behave like soaps we use
in other contexts. Typically it is made from metal compounds reacted
with acid, not with fats reacted with alkali, like the soaps we're
familiar with, and it isn't generally water soluble.


Sorry... that's not even close, Ed. Even the soap you use in your
bathroom is a "metallic soap", unless you don't include sodium or
potassium in your list of metallic elements.

Bath soap is usually a strongly alkaline substance like sodium or
potassium hydroxide mixed with animal fat or vegetable fat, then allowed
to 'saponify' (turn to soap, in English).

The soaps for lubricating greases are strongly alkaline substances (like
lithium hydroxide) mixed with FATTY ACIDS (that is NOT an 'acid' like you
cite... you'd make folks think sulfuric or nitric or hydrochloric). They
typically use stearine. But guess what? Sterine is a room-temperature-
solid fatty acid derived from pork fat or beef fat.

The fatty acid will react to form the 'lipid tail' with an alkaline
'head' -- JUST like bath soap. The tail attracts oils, the head water.
So it can emulsify oily things into a water suspension -- not actually a
'solution'.

So, in all, the soaps used to make lubricating greases are JUST like bath
soap, except for their choice of alkali metal salts that are non-
corrosive.

Lloyd

Except that most of the metallic soaps used in greases and dryers are
not water-soluble, regardless of how you want to describe the
chemistry.

The key point is that they don't behave at all like the water-soluble
bath soaps and other soaps we're familiar with. Lithium soap is
slightly water-soluble, but most others are not.

--
Ed Huntress