This report covers
- BB is no grease expert
- Moly grease
- Moly that’s not good
- Petroleum-based grease
- When to use grease
- BB greased the train tracks!
- Lithium grease
- Tune in a Tube
Today we will talk about grease and how it relates to airguns. Reader CptKlotz, who is Stephan from Germany, asked about the grease I used on the Benjamin 397 trigger parts and I said I would write a report on it. I told my neighbor, Denny (Sawdust), and he said he would be interested in learning more about grease, too.
BB is no grease expert
I’m learning this stuff as I write this one. I know a little about grease, as it applies to things like wheel bearings and airguns, but I am far from being an expert. My research for this report taught me a few things.
First off — don’t Google Grease or you will get page after page of references to the movie that starred John Travolta and Olivia Newton-John. You have to put the word lubrication next to grease to get anywhere.
Grease is a solid or semisolid lubricant made from a liquid lubricant and thickening agents. It has high viscosity until shear (pressure) breaks it down to form an oil-like substance. I said when I lubed the hammer of my 397 that I wanted the oil-like part of the lithium grease that I used because I didn’t want the semisolid grease to slow the hammer down.
The most common type of grease consists of soap used with something like mineral or vegetable oil mixed to make an emulsion (two liquids mixed to form something called a colloidal suspension). But sometimes the mixture is a liquid and a solid. Let’s start there with something called molybdenum disulphide.
Moly grease is a mixture of a dry solid particle, called molybdenum disulphide, suspended in a grease (yes — that is another emulsion) “vehicle.” In this instance the term “vehicle” means something that the moly particles are mixed in that helps to spread the solid particles around. You see — not all moly comes as a grease.
Moly by itself is a dark gray powder that can be spread directly on metal parts to which it bonds and forms a super-slick surface. Several decades ago I went in with the Springman, Jim Maccari, and we split an order of moly powder. I ended up with a 10 ounce jar of this dark gray powder that works just as I have explained and am about to show you.
Moly powder bottle.
A cotton swab is rolled in the moly powder and picks up just the right amount.
My steel back scratcher will serve as the metal surface.
The dark spot in the center is where the moly powder was burnished in with the cotton swab.
Let’s read the directions.
That’s what moly is and that’s what it can do.
And that is how it is applied.
So the moly grease we buy is moly powder mixed with grease so it will apply easier. The more moly particles in the grease, the better. I bought the powder in case “they” ever stop selling moly grease. I’ll make my own by mixing the powder with white lithium grease.
Moly that’s not good
Years ago Beeman sold a moly that was suspended in a solvent vehicle. It was called Dri-Slide. The solvent removed all lubrication from metal surfaces and promoted rust. I rusted several airguns with the stuff before learning not to use it.
The most common type of grease is petroleum-based. Most shops have this kind of grease on hand because it is used so widely. What is used to thicken it determines what it is to be used for. While these greases may have started as oil, their thickeners turn them into the products they become and they no longer act like the oil that’s in them.
When to use grease
Oil works well for lubrication. Why would you use grease instead of oil? One word comes to mind — viscosity. Grease stays put for many years, where oil eventually runs off, leaving the metal parts without lubrication. So you grease parts that are never or infrequently oiled. I’ll give you an example.
Greases labeled EP are for applications where extreme pressure is anticipated. And the center bearing of a train’s freight car truck (where the train’s car wheels are held together under the freight car) comes to mind as one of the hardest applications for grease. It’s not a place that gets greased that often and the pressure must be enormous!
The center plate of a rail car truck (arrow) connects the wheels to the car. It doesn’t get greased very often and it bears a lot of weight.
Several special dry “packages” consisting of a steel ring inside a grease-inpregnated plastic envelope are tossed into the center plate when the car is lifted off the truck. Imagine just how often that happens! Probably only when they need to change the graffiti on the side of the car.
The steel ring inside the envelope is a softer steel than the center plates of the truck and the car, and it wears away over time. The grease is there to do its greasy thing, but without that steel ring the truck would have to be greased a lot more frequently.
BB greased the train tracks!
When I worked at Frontier Village amusement park in San Jose, California in the late 1960s, I was Casey Jones for a time. That meant I was the engineer who ran the railroad. We had about a 1.2-mile track and the train hauled up to 80 people around the park on each trip.
Every morning my first job was to polish all the brass poles on the merry-go-round and after that I had to grease the rails for the train. On the curves I applied a thick grease to the inside rail of the curve — the part where the wheel flange stopped the wheel from leaving the track. That was every morning. It kept the wheels from squeaking as they rubbed against the track.
I remember one day it was misting (it doesn’t rain in California) and after I greased the tracks I couldn’t stop the train. I applied the brakes at about 2-3 m.p.h and instead of stopping in 100 feet it took 500 feet to stop. I slid right through the station when I arrived after a trip. When it happened old BB said some bad words and he forgot that he had the push-to-talk button on his microphone pressed! Bad BB! Potty-mouth BB!
Now that you know what grease is — a colloidal suspension of two liquids — what of it? Well, if the place we want to grease won’t be under extreme friction or subjected to water, other greases work best. Lithium is the basis of many greases and white lithium grease is a favorite for airgunners. You can get it at any automotive store or hardware store and it isn’t expensive. It won’t handle the same shear force (pressure) that moly will, but for many applications it is good enough. Most imporantly its lower viscosity doesn’t rob any motion, which to us means velocity.
For springers like lower-powered Dianas (the 25 and 27 come to mind) lithium grease is great for almost everything. It does soak up some vibration that moly grease doesn’t, and it lasts for a long time. Remember, grease is just a way of getting oil to remain in place.
Tune in a Tube
Wheel bearing greases have improved over the years and we are reaping the benefits. Almagard 3752, which we know as Tune in a Tube, is one example of a very high-viscosity wheel bearing (and many other bearings) grease. It is water-resistant (something lithium greases are not), and resistant to heat, pounding and slinging, plus it doesn’t harden over time. And it reduces vibration like no other grease I know of.
It contains Almasol, a solid wear-reducing additive that handles heavy loads, resists chemical attacks and can handle heat up to 1,900 degrees F. It forms a microscopic layer on metal but does not build on itself, so tolerances are maintained.
It also contains Quinplex that resists impacts, has high tackiness and is water-resistant. It helps forming a barrier against corrosion.
Yes, you can buy Almagard in 14-ounce grease-gun tubes, but Tune in a Tube is a little cheaper, plus it comes with its own applicator. For the hobbyist it’s the best deal.
I have touched lightly on greases today. I haven’t even addressed things like medical-grade greases or food-grade greases. Nor have I mentioned petroleum jelly like Vaseline, which, strictly speaking, isn’t grease at all. I’ve tried to stick with the greases that airgunners might use.