What's so special about 'marine' grease?

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May 20, 2019
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British Columbia, Canada
Looking for a high quality grease for use on truck suspension parts (ball joints, greasable control arms, etc) as well as trailer bearings. For trailers everyone seems to suggest 'marine' grease.

Trying to figure out how it is different from other grease?? Looking at some of the marketing for marine greases, they keep saying "waterproof" and "resists corrosion" - doesn't ALL grease do that?

Also, if marine grease is somehow more waterproof and more corrosion resistant, why isn't it just used everywhere, why even bother with other greases??

For context, I live in the PNW, so lots of rain and lots of road salt in the winter. I currently have Lucas X-Tra Heavy Duty Grease in my grease gun. Also have a big tub of Motorex 'FETT 2000' which I use on my dirt bike and mountain bike. Trying to figure out if I really need a second grease gun full of marine grease for the trailer...
 
I believe that it resists water better than other greases do. It resists being washed off and resists corrosion. I would say though that it doesnt handle high loads or high speeds as well as some other greases do.
Thats why they make so many different kinds of greases, each is for a certain situation.
 
I believe marine greases are calcium-based and have superior resistance to water washout. Lithium-based greases, which are widely specified for automotive use, also have good washout resistance. I'm not sure of the pros and cons nuances between the different based greases beyond that.
 
If you ever have repacked wheel bearings that have been submersed in water and the water got into the bearings and the grease has changed from a normal color to a different color and now has water absorbed into the grease and lost some of its ability to properly lubricate and also no longer protects the metal of the bearings from rusting, you would know why some people like marine grease. If you pack boat trailer bearings with marine grease and water gets in, the grease holds up and does not change its color and lubricating ability, and the water stays separate from the grease. It is a big deal with bearings that actually get water into them. The difference is big, like night and day.
 
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Unless you're putting boats in the water, I would just use the Lucas grease you already have. I believe that it is a polyurea type grease so it may not be compatible with the more common lithium soap type greases so make sure to clean any existing grease from your bearings before applying.
 
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Unless you're putting boats in the water, I would just use the Lucas grease you already have. I believe that it is a polyurea type grease so it may not be compatible with the more common lithium soap type greases so make sure to clean any existing grease from your bearings before applying.

This is a snowmobile trailer, so no salt water immersion like a boat would see. Having said that, it does see lots of off-pavement driving, plenty of muddy/snowy logging roads with creek crossings and such.

You are right in that X-tra Heavy Lucas is polyurea based grease. I do remember reading that it is a "shear stable" polyurea, meaning it is compatible with lithium greases. Having said that, I do agree that best practice is to clean bearings and start fresh whenever switching greases.
 
The sodium ions in sea water can play havoc with greases. Many marine greases are aluminum based to provide far more resistance to sodium ion and prevent the grease from breaking down after salt water immersion. Even "fresh" water can have considerable sodium ion in it, particularly after a winter where a lot of salt has been used on the roads.
 
Looking for a high quality grease for use on truck suspension parts (ball joints, greasable control arms, etc) as well as trailer bearings. For trailers everyone seems to suggest 'marine' grease.

Trying to figure out how it is different from other grease?? Looking at some of the marketing for marine greases, they keep saying "waterproof" and "resists corrosion" - doesn't ALL grease do that?

Also, if marine grease is somehow more waterproof and more corrosion resistant, why isn't it just used everywhere, why even bother with other greases??

For context, I live in the PNW, so lots of rain and lots of road salt in the winter. I currently have Lucas X-Tra Heavy Duty Grease in my grease gun. Also have a big tub of Motorex 'FETT 2000' which I use on my dirt bike and mountain bike. Trying to figure out if I really need a second grease gun full of marine grease for the trailer...

The Lucas X-Tra Heavy Duty grease you have says it's "virtually waterproof" but it's not marine grease... I think the grease you have will work based off your stated application and the information I'm seeing. FWIW, I use Lucas Red N Tacky in my camper wheel bearings and all the other zerks around my place on my Ram, LT150 etc... Red N Tacky states it is "water resistant"

just my $0.02
 
Looking at the SDS for Lucas marine grease:

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Looks like it's calcium soap based grease; specifically a Calcium Sulfonate based grease.

Found a good article comparing Lithium soap vs Calcium Sulfonate: https://www.machinerylubrication.com/Read/29658/multi-purpose-grease

"Unlike lithium-complex greases, which need a significant amount of antimony-zinc or other types of additives, calcium-sulfonate thickeners have inherent extreme-pressure and anti-wear properties. In addition, while sulfonates are known to be natural rust inhibitors, lithium-complex greases invariably need rust-inhibiting additives.

Furthermore, calcium sulfonate, by virtue of its thickener property, provides excellent water-resistance properties and does not break down even in the presence of water. To improve their water-resistance properties, lithium-complex greases usually require tackifiers, which are prone to deplete quickly in the presence of water. Calcium-sulfonate greases are also compatible with lithium and lithium-complex greases.

The only limitations with calcium-sulfonate greases are their inferior pumpability and cost. However, recent technological advances have brought these greases up to par with lithium-complex greases. A calcium-sulfonate grease can also be applied in more types of industries compared to lithium-complex greases, thus making it the preferred choice for a high-performance multi-purpose grease."


One take away that's interesting from the blurb above is sounds like lithium greases CAN be made more waterproof and more corrosion resistant, but that is achieved via additives:
  • Tackifiers (adds water resistance)
  • Zinc -> I'm guessing similar to zinc plating on bolts; zinc corrodes first and acts as an sacrificial element preventing the actual metal from rusting! Very cool.
But sounds like additives have their disadvantages, and it's likely better to have the base soap actually exhibit these properties, hence the use of calcium in marine grease. Makes sense!
 
You can drop a pile of bricks on it, like the aluminum bed of a Chevy truck, and it won't puncture it. THAT is, "military grade".
GM trucks use various grades of steel in “fixed panels” - and aluminum “swing panels” (door, hood, etc)
 
The Lucas X-Tra Heavy Duty grease you have says it's "virtually waterproof" but it's not marine grease... I think the grease you have will work based off your stated application and the information I'm seeing. FWIW, I use Lucas Red N Tacky in my camper wheel bearings and all the other zerks around my place on my Ram, LT150 etc... Red N Tacky states it is "water resistant"

just my $0.02
The Tie Down Engineering (now Dexter) axles on my boat came packed with RnT … so I stayed with that and it‘s great. Later I noticed they switched to Lucas Marine - but I didn’t bother …
 
GM trucks use various grades of steel in “fixed panels” - and aluminum “swing panels” (door, hood, etc)

You're right. I had them mixed up. It was Ford who came out with the all aluminum truck bed in 2015. That's when Chevy came out with the commercials knocking them. By dumping loads of bricks and crap into them, tearing and splitting the beds open. Ford advertised "strength" by making the claim their trucks were made from, "Military Grade Aluminum"....... Whatever the hell that is.
 
Getting back to the original question which was what is so special about marine grease, most waterproof greases will be aluminum complex, lithium complex, calcium sulfonate and, less often, mixed soaps. No commercial waterproof grease is truly waterproof however a few may come close. Many are
For many applications calcium sulfonate does not need to be additized having adequate inherent capabilities. Other greases require additives to improve wear control and rust prevention. However, this may not be an issue from a cost standpoint. In many cases, total additive cost is lower than calcium sulfonate thickener cost.

If I were looking for a grease for use in a saltwater environment, I would look for one with an ASTM D6138 Corrosion-Preventive Properties of Lubricating Greases Under Dynamic Wet Conditions (Emcor Test) using synthetic (or natural) seawater rating of 0, 0 or, at worst, 0, 1. These ratings mean there is little to no rust on the test bearing race. This is not difficult to achieve using the correct soap in combination with the correct rust inhibitors at an effective treat level.

The most waterproof or water-resistant grease that I’ve seen is Bel-Ray Waterproof Grease. This was an aluminum complex grease with a mineral oil base fluid modified with barium complex grease which adds adhesion and resistance to water infiltration. The downside of this blend is poor pumpability. For this reason, the grease was sold into the Powersports industry where applications are manual such as wheel bearings or swing arm bearings. I don’t know the grease’s formula so I can’t comment on its wear control and Emcor performance.
 
The Lucas X-Tra Heavy Duty grease you have says it's "virtually waterproof" but it's not marine grease... I think the grease you have will work based off your stated application and the information I'm seeing. FWIW, I use Lucas Red N Tacky in my camper wheel bearings and all the other zerks around my place on my Ram, LT150 etc... Red N Tacky states it is "water resistant"

just my $0.02

And as per Lucas, their xtra heavy duty grease does NOT mix with their red or Marine grease and you must thoroughly clean (bearings etc) before switching.
Glad I emailed them today because that was next in my grease gun.
 
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