Marine Grease vs. Regular Grease

To understand the differences between marine grease vs. regular grease, we must analyze various factors and ingredients. The first area to look into is the type of thickener that is blended with the base stock oil to create the grease. The majority of regular mineral based marine greases and regular greases utilize lithium soaps. During the formulation of these grease are added your basic additive chemistry such as extreme pressure additives, rust and corrosion inhibitors, and other additives to improve the grease’s ability to handle water.

Initially, we’re setting the table only in discussing conventional or regular marine grease and regular grease. Understand that lithium soaps inherently do not make great water resistant greases. Other specialized additives must be added to lithium soap thickeners to give them some capability in dealing with moisture. Ultimately, there is too much compromise between getting the oil to perform not only in regular environments but also environments with abundant moisture and water. There are much better choices of thickeners that would create a very water resistant grease.

Characteristics of Marine Grease vs. Regular Grease

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When a grease formulator sets out to custom blend a grease that can be truly considered a water resistant marine grease, thickeners must be carefully understood and considered. In terms of pure water resistance, a lithium soap is typically removed from the list of choices when wanting to create a specialized water resistant grease. Better choices of thickeners would be aluminum complex or calcium-sulfonate soaps. Both are quite water resistant and are considered anti-corrosion agents.

AMSOIL Synthetic Polymeric Off-Road Grease, NLGI #2.
AMSOIL Synthetic Polymeric Off-Road Grease, NLGI #2

For this blog post we’ll discuss the best choice, which would be calcium-sulfonate soap thickeners.

At this point, we can say that a marine grease or water resistant grease is a grease specifically formulated for wet duty performance. Base oils and thickeners are carefully chosen so that they offer the ultimate in water resistance and can cope with large amounts of water.

On the other hand, a regular grease is not formulated to operate in any environment where there is water. This type of grease is more for general purpose lubrication to protect chassis points and bearings under light duty applications where little or no water comes in contact with the grease.

Lithium soaps are typically used for regular grease and very little thought or consideration is given to the additive chemistry to make the grease more water resistance because the formulator knows the grease is really not designed to be water resistant.

Making the Grease Water Resistant

When creating a grease that offers outstanding water resistance and performance, it is necessary to engineer this grease with high performance adhesive and cohesive chemistry. The adhesive additive provides the grease its clingability, allowing it to stick to metal surfaces when wet. The cohesive additive holds the grease together when exposed to water. The cohesive and adhesive characteristics of this marine grease allows it to protect parts that are exposed to water and pressurized water over long periods of time.

To test an oil’s ability in being resistant to water exposure, the grease is put through the industry standard test known as the ASTM D-1264 Water Washout @79 degrees C. Conventional greases typically score 20% or higher when put through this test. Lubricant manufacturers that formulate regular grease with some water resistance will typically score an average of 7% to 10% on this industry test.

What kind of score would a true water resistant grease rate when run through this water washout test. Let’s take a look at a specific brand of marine grease from AMSOIL. AMSOIL’s Synthetic Water Resistant Grease was engineered specifically for any marine or high moisture environment. When it was tested on the ASTM D-1264 Water Washout Test, it scored an outstanding 1.25%.

AMSOIL Synthetic Water Resistant Grease.
AMSOIL Synthetic Water Resistant Grease

When compared to other regular “water resistant greases” and standard greases, this 1.25% rating is quite amazing. The combination of synthetic base oils, superior additive chemistry, rust and corrosion inhibitors, and the toughest adhesive and cohesive agents, gives AMSOIL’s Synthetic Water Resistant Grease industry leading performance.

Even in the presence of large amounts of standing water or pressurized water, it will not lose any of its greasing abilities and will also maintain its EP abilities. Conventional greases, if used in any high water environments, literally will wash away and leave metal components and surfaces unprotected. They are not able to withstand high amount of water. A true water resistant marine grease maintains its additive chemistry and integrity and will not wash away. It is able to perform even in extreme pressure environments while exposed to large amounts of water.

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This ability to retain all its properties and characteristics is one of the main differences when one analyzes the difference between marine grease vs. regular grease. It cannot be emphasized enough that regular greases, when in the presence of water, will lose many of it lubricating capabilities. If a regular grease that is not water resistant is used in any heavy equipment that is exposed to water, then the chances of coping with extreme pressure or shock loads will dramatically drop.

If the grease cannot withstand exposure to water, then quite quickly many if its lubricating properties will literally be washed away. The end result is excessive friction and wear, large grease consumption, and unfortunately catastrophic parts failure.

It is clear at this point that if your vehicle, trailer, boat, or heavy equipment could and will be exposed to water, then it is critical to switch to a specialized water resistant grease.

Protect Parts from Rust and Corrosion

If components are exposed to moisture and water often and over long periods of time, then the chance of rust and corrosion will go up. If your grease is not water resistant and properly formulated with extra volumes of rust and corrosion inhibitors, then metal surfaces will become damaged due to the corrosion, which leads to compromised parts.

For those applications where exposure to water, snow, ice, and mud are quite extensive, then it’s very important to choose the best possible water resistant marine grease. This type of specialized grease will create a seal of protection onto the metal surfaces and will chemically guard against any corrosion.

Extreme Pressure and Load Carrying Capabilities

If a piece or equipment or vehicle will be exposed to shock loads, heavy loads, extreme pressure, or water, then it is vitally important to use a water resistant grease that has been formulated with extreme pressure additives. These extreme pressure additives can protect parts from metal-to-metal contact when exposed to shock loads, heavy loads, or sustained extreme pressure.

We’ve already mentioned what happens to a regular grease that is exposed to water. Over time, a non-water resistant regular grease will be washed away by constant exposure to water and moisture. Also, a regular grease will lose its extreme pressure performance capabilities due to water exposure that breaks down and degrades the grease and its performance capabilities.

To further understand extreme pressure capabilities of a grease, one must look and see how the grease has performed during the ASTM D-2509 Timken OK Load Extreme Pressure Test. Conventional and regular greases typically score 35 to 40 pound Timken OK Load ratings when tested. This 35 to 40 pound Timken OK Load rating is before the grease is exposed to any water. Having such a grease exposed to water will quickly deplete the grease’s ability to withstand shock loads and extreme pressure.

In comparison, AMSOIL’s Synthetic Water Resistant Grease was tested on the Timken OK Load Test and scored a 75+ pound rating. This is an outstanding superior load rating. In addition, due to its extreme water resistance, even when exposed to high volumes of water, this water resistant grease will maintain its high Timken OK Load abilities, keep metal surfaces protected, and withstand tremendous amounts of load.

When comparing a marine grease vs. regular grease, looking at the differences in Timken OK Load ratings is another factor when deciding which is the best grease for both water resistance and extreme pressure protection.

Oil Separation

The next property to compare when analyzing marine grease vs. regular grease is to look at how the grease tests on the ASTM D-1742 Oil Separation Test. What is oil separation? This is where the oil literally begins to separate from the thickener. You may have looked inside a cartridge of grease that has been on the shelf for some time and you take the cap off and you notice oil literally floating on top. Also, you may have seen that some of the oil has leaked out of the grease cartridge and onto your shelf. This is oil separation.

An excellent analogy is to take the top off a new jar of peanut butter. Notice the peanut oil floating at the top. The same oil separation takes place with regular or conventional poorly designed and blended greases. What is the importance of understanding what oil separation is in regards to grease?

If the oil is leaking out and separating from the thickener while sitting in the box or on the shelf, then what is going to happen once this grease is put into service? The obvious goal is to have the oil lubricating your parts and components and not leaking out and separating from the thickener. Conventional or regular greases will typically score 6% oil separation during this industry standard test. AMSOIL’s Synthetic Water Resistant Grease scored 0.00% oil separation. This grease was blended and formulated correctly, the grease retains 100% or its oil, and when you utilize the oil in your machinery, it is is there to provide maximum lubrication and protection.

Ask yourself the question: which grease would you rather use? A grease that leaks out before you even have a chance to utilize it? Or a grease that doesn’t leak out and separate from the thickener?

Reduce Wear

Obviously, equipment exposed to large amounts of moisture and water need to be waterproof, but also equally important is that it is engineered with the proper lubricating oils and additive chemistry that helps to protect metal surfaces from friction and wear. To analyze a grease’s ability to protect from wear, one can check how the grease performed during the industry standard test called the ASTM D-2266 Four Ball Wear Test D,MM.

The lower the score or number, the less wear or less scarring of the metal surface. The test scores are specified in millimetres (mm). A conventional or regular lithium soap based grease will score a 70 to 90 millimetre wear/scar mark. AMSOIL’s Synthetic Water Resistant Grease scored a 0.42 millimetre scar mark. When comparing wear or scar marks between the marine grease vs. regular grease, the marine grease offers half as much wear as the regular grease.

AMSOIL Synthetic Water Resistant Grease.
AMSOIL Synthetic Water Resistant Grease

Remember, if a grease does not offer excellent water resistance, then its ability to lubricate and protect against wear will literally be washed away when exposed to water. It is another example of why it is important to understand the basics of what type of lubricants are being utilized in equipment or vehicles and what range of environments will that equipment or vehicle be exposed to.

For those that operate in extreme conditions and where water will definitely be present, it is doubly important to utilize only the finest possible water resistant grease.

Utilizing a water resistant grease as an important part of your maintenance program is not only logical, but also an important strategy to protect the large investment in your vehicles or equipment.

Recommended Applications

It is a good idea to see if the grease you’re choosing meets the standards established by the NLGI, which stands for the National Lubrication Grease Institute. Here are some of the basic standards they have set and the designation that earmarks a grease that meets and performs at these standards. See if the grease meets GC, which is for wheel bearing applications. Next, check if it meets LB, which is for chassis applications. For the most common weight, see if it is a NLGI #2.

AMSOIL Synthetic Water Resistant Grease meets the high performance standards set by the National Lubrication Grease Institute. Its designation is NLGI #2, GC-LB. It can be utilized in chassis, automotive wheel bearings, and other applications where a NLGI #2 GC or LB grease is specified.

This blog post has presented differences between marine grease vs. regular grease. Take that information and decide which type of grease will best suite your equipment. Remember, the cheapest and best grease is the one that protects your vehicle or equipment from all elements and provides that equipment with long dependable service life.