An Education in Grease
WHAT IS GREASE?
According to the Practical Handbook of Lubrication, grease is a lubricant
composed of a fluid lubricant thickened with a material that contributes a
degree of plasticity. Greases are typically used in areas where a continuous
supply of oil cannot be retained, such as open bearings or chassis components.
Greases are comprised of two basic structural components: a base fluid and a
thickening agent. Different types and combinations of thickeners and base
fluids, along with supplemental structure modifiers and performance additives,
combine to give the final product its special lubricating properties.
Base Oil - Many different types of base
oil may be used in the manufacture of a grease, including petroleum (napthenic,
parafinic) and synthetic (PAO's, esters, silicones, glycols). Just as with
motor oils and transmission fluids, the viscosity of the base oil is the most
significant property. A lighter, lower viscosity base oil is used to formulate
low temperature greases, while a heavier, higher viscosity base oil is used to
formulate high temperature greases.
With outstanding lubricating
abilities in temperature extremes, AMSOIL greases offer a wider range of
application than conventional greases.
Thickener - Thickener is the term
describing the ingredients added to a base oil in order to thicken it to a
grease structure. The two basic types of thickeners are organic thickeners and
inorganic thickeners. Organic thickeners can be either soap-based or non-soap
based, while inorganic thickeners are non-soap based.
Simple soaps are formed with the
combination of a fatty acid or ester (of either animal or vegetable origin)
with an alkali or alkaline earth metal, reacted with the application of heat,
pressure or agitation through a process known as saponification. The fiber
structure provided by the metal soap determines the mechanical stability and
physical properties of the finished grease.
In order to take on enhanced
performance characteristics, including higher dropping points, a complex agent
is added to the soap thickener to convert it to a soap salt complex thickener.
The greases are then referred to as "complexes" and include lithium
complex greases like those provided by AMSOIL.
Additives - Chemical additives are added to
greases in order to enhance their performance, much like the additives added to
lubricating oils. Performance requirements, compatibility, environmental
considerations, color and cost all factor into additive selection.
Grease consistency correlates to the firmness of the grease. Depending on the
applications they're designed for, greases can range from semifluid
consistencies to almost solid. Care must be taken to select the correct
consistency for the application. If the grease is too hard, it may not
adequately flow to the areas in need of lubrication. If it is too soft, it may
leak away from the desired area. Since consistency directly correlates to
pumpability, equipment greased through a dispensing system may require a grease
representing a compromise between what is required for lubrication and what can
be adequately pumped.
Consistency is measured with the
ASTM Cone Penetration Test D 217. Under prescribed conditions, a standardized
cone is allowed to drop into the grease for 5 seconds. The level of penetration
is measured to determine its NLGI consistency number, ranging from 000 to 6. The
higher the penetration number, the lower the consistency number.
Oxidation stability has to do with
the performance of a grease after being exposed to oxygen. Both the ASTM D 942
Bomb Oxidation Test and the ASTM D 3527 High Temperature Bearing Life Test are
used to measure oxidation.
Exposure to water may effect
greases in several ways. First, it can cause grease to change consistency,
becoming softer or firmer. Second, it may change the grease's texture, perhaps
becoming less adhesive. Third, it may form an emulsion with the grease, losing
its lubricating effectiveness or washing away.
The Water Washout (ASTM D 1264)
Test and Water Spray Off (ASTM D 4049) Test measure the amount of grease washed
away from various water washing and spraying conditions. The Rust ASTM D 1743
measures rust inhibiting characteristics and the ASTM D 4048 measures copper
A lubricant's main job is to
separate bearing surfaces to prevent wear. If the amount of lubricant is
inadequate, the lubricant film becomes so thin that some parts come into
contact with part of the surfaces being separated. Known as boundary
lubrication, it causes a modest level of wear on one or both bearing surfaces.
Lubricants differ in their
load-carrying abilities, sometimes keeping the film thicker and sometimes
acting chemically on the surfaces to prevent them from welding.
Three separate tests for
load-carrying capability are used. The Four-Ball Wear ASTM D 2266 measures wear
at light loads, while the Four-Ball EP ASTM D2596 and Timken EP ASTM D 2509
indicate more severe wear or welding.
AMSOIL offers a full line of premium synthetic lubricating greases, including
X-Treme Food Grade Grease and
Water Resistant Grease. AMSOIL greases
effectively reduce friction and wear, keeping components running clean and
AMSOIL Multi-Purpose GL Series of greases
consist of the GLA (NLGI #0), GLB (NLGI #1 GC/LB) and GLC (NLGI #2 GC/LB)
grades, as well as the GLC Multi-Purpose Spray Grease. The greases in the GL
Series contain the same viscosity base oils and additives, but contain
different amounts of thickener. GLA contains the least thickener, making it
more suitable for cold temperature applications, while GLC contains more
thickener, making it better suited for high temperature, moisture and speed
AMSOIL Multi-Purpose Greases are
ideal for automotive wheel bearings and electric motors, while the
Multi-Purpose Spray Grease works perfectly for hard-to-reach equipment such as
hinges and springs.
AMSOIL Heavy-Duty GH Series of greases
consist of the GHB (NLGI #1 GC/LB) and GHD (NLGI #2 GC/LB) grades. AMSOIL GHB
and GHD contain the same viscosity base oils and additives, differing only in
the amount of thickener. GHB contains less thickener than GHD, making it ideal
for cold weather applications.
AMSOIL Heavy-Duty Greases provide
outstanding protection in four wheel drive steering knuckles, spring shackles
and other components exposed to high-load, high-speed conditions. AMSOIL GRG
Series 2000 Racing Grease (NLGI #2 C/LB) is
ideal for vehicles in which the brakes are applied frequently. It offers
unsurpassed high temperature protection, providing the ultimate protection for
hard-driven, high-performance vehicles.
AMSOIL GWR Water Resistant Grease (NLGI
#1.5 GC/LB) provides outstanding performance in wet environments, such as those
found in boat trailer wheel bearings. It effectively resists both water washout
AMSOIL GXC X-Treme Food Grade Grease (NLGI
#2 H-I) provides superior, non-toxic lubrication in food and pharmaceutical
industry equipment. It reduces friction, wear and heat in temperature extremes
from -35°F to 400°F.
AMSOIL Synthetic GVC Lithium Complex High Viscosity
Grease (NLGI #2) is a lithium complex thickened grease blended with
premium ISO-320 synthetic base oils. This grease is fully compounded with additives
providing EP protection, oxidation resistance and rust and corrosion
protection. AMSOIL GVC is shear stable, maintaining its viscosity and
consistency in the presence of mechanical activity, and GVC stays in place by
resisting water washout.
AMSOIL Spy Grease is a lithium complex
semifluid grease (NLGI 00) formulated with high-viscosity ISO-460 synthetic
base oils. Coupled with a sophisticated additive package, AMSOIL SPY GREASE
coats and reacts to metal surfaces, providing an unparalleled protection system
that reduces wear and prevents damage.
AMSOIL Spy Grease is a
problem-solving lubricant ideal for leaky gear boxes in industrial and fleet
applications and for use in applications that are difficult to service. It is
primarily used in grease-filled cases where conventional semifluid greases do
not provide adequate lubricant life or protection. AMSOIL SPY GREASE is the
primary grease recommendation for truck wheel hubs as outlined in RP 631,
issued by The Maintenance Council of the American Trucking Association.
I welcome the opportunity to work with you personally as your servicing
AMSOIL Dealer. Use the information on this website to contact me. You may also
check out the AMSOIL Corporate Website for product and
business opportunity information.