Oils come in many different viscosities -- light machine oil or
vegetable oil will have less viscosity than, say, motor oil, and some
may retain their low viscosity at low temperatures. Try experimenting
with various oils.
Other compounds may suit your requirements but may have other undesirable or hazardous properties. For example,
Freon -- mostly inert, but it evaporates easily, does not degrade,
and harms the ozone high in the atmosphere. It also dissolves oils and
fats easily and can soak through your skin. Not good to ingest! It has
low viscosity at low temperatures, however. It may be difficult or
impossible to obtain because of environmental regulations.
Gasoline -- very flammable! Evaproates easily, and the vapors are explosive. It's poisonous, too. Widely available.
Xylene -- this is the stuff that makes magic markers smell so bad. It is also flammable.
Turpentine -- flammable, evaporates easily, poisonous.
Used to dilute artists oil paints.
Most hydrocarbons are insoluble in water and many are liquids at
room temperature with low viscosities. Unfortunatley, most are
flammable or poisonous or both.
(published on 10/22/2007)