Metalworking fluids all start on the formulator’s chemistry lab
bench, where chemists blend together various compounds, much
like a kitchen recipe. Most of these ingredients are publicly
known and governmentally approved as being safe. A few
ingredients are proprietary. Both will be listed on the fluid’s
Material Safety Data Sheet, or MSDS. Just knowing the
ingredient, however, is not enough to make the coolant yourself-
how it is used, at what stage of the recipe, and exactly how it
is added are also critical to its function. The main property
the chemist will impart is the ability for the coolant to
emulsify into water (except straight oils) and remain stable as
an emulsion over a wide temperature range. Other properties are
for the coolant to prevent rust on parts and machines, reject
tramp oils which cause biofilms and excessive mist, provide the
right amount of lubricity so tools and metals do not weld
together, and to prevent foaming. Biocides will be added to the
recipe as well, in safe amounts, to pre