Re: How does the glycerin in fog fluid help produce fog?

Tyler,

I too wondered about fogger operation but never pursued it until now.  I 
followed your lead and logged into the Radio Shack web site you listed in 
your question.  There were operations manuals and Material Safety Data 
Sheets (MSDS), but no direct information about the fluid.  I gleaned the 
following:

1.)  A water solution of glycerol is sprayed onto a hot (300 deg. F) metal 
plate.
2.)  The glycerol is evaporated and produces a thick white fog.  The plate 
must be heated again before the process can be repeated.  The process is 
similar to an automobile engine buring oil, but glycerol is non-toxic.  
People with respiratory problems will probably have problems breathing 
even glycerol fog.

Glycerol is a triple alcohol with the forula (OHCH2-CHOH-CH2OH).  Until 
1948 the sole source for glycerol was as a byproduct of soap making.  
Animal and plant fats and oils are comprised of glycerides, or complex 
molecules made up of one molecule of glycerol and one, if a monoglyceride, 
two, if a diglyceride, or three if a tirglyceride.  If the fatty acids 
have one or more double bonds,the gylceride is said to be unsaturated and 
you have an unsaturated fat.  If the fatty acids have no double bonds, it 
is said to be a saturated fat.  The molecule is saturated with all the 
hydrogen atoms the molecule can hold.  When the oils or fats are heated 
with sodium hydroxide, the molecules separate, liberating the glycerol and 
making three molecules of soap ( sodium stearate or other sodium-fatty 
acid salt.)  This makes the familiar hard or bar soap.   If potassium 
hydroxide is used, soft or liquid soap is produced.

Since 1948, increasingly glycerol is being produced directly from 
propylene gas and from sugar.

Glycerine is a term used to describe water/glycerol solutions of at least 
95% glycerol. 

There are thousands of uses for glycerol.  The Encyclopedia Britannica has 
an adequate introductory article on Glycerol.  On-line sources should also 
give reasonable information.