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WHAT'S INSIDE YOUR CAN OF GRAPHITE?
NOT ALL GRAPHITE DRY LUBRICANTS ARE THE SAME

Like with many products, it is sometimes very difficult to tell what is in the packaging. How does it really look? How does it really perform? Is it enough for what I need? Ultimately, am I getting the best value? Most agree that one cannot necessarily judge a book by its cover. This is very true when it comes to graphite lubricants in the marketplace. All aerosol and paint cans look the same, but the contents inside can be extremely different. Superior Graphite reviewed and tested nine (9) graphite dry film lubricants in the marketplace to see what we might find.

Perception is not everything. How much is really in the can?
Product packaging is a huge industry that plays on the psychological game of making products seem more when there is less. Take for example nine competing aerosol cans of dry graphite lubricants in the table below. They all share the same standard 16-ounce aerosol can, but comparatively, they all have different net weights of product inside. In the case of aerosol cans, the difference in net weights can be due to different formulary reasons like mixing ability and propellant choice. For whatever reason, at the end of the day, how much product did you purchase for the price you paid? Did you get a good value or did you get short-changed?

Dry Film Graphite Aerosol Lubricants
Weights and Percent Solids

Product Brand Net Weight % Solids
A 5.5 oz 1.8%
B 10 oz 0.9%
C 10 oz 1.5%
D 10.5 oz 0.7%
E 10.5 oz 0.8%
F 11 oz 25.2%
G 12 oz 1.6%
H 12 oz 41.9%
Slip Plate® 12 oz 21.4%

Reality counts. What's inside the can?
Many believe that graphite lubricants are a commodity product. In other words, all rattle/paint cans of graphite coatings are all the same. In reality, there are two (2) main things that govern the performance of the graphite lubricant that you purchase: amount of graphite and the type of graphite.

How much graphite is really in there?

hardware storeI was recently in my local hardware store looking to purchase some paint for our attic. I found a sale priced paint and took it to the mixing counter for my color choice. The counterperson suggested that I get a couple gallons more because one coating would end up very thin as there really wasn't much solids in the paint. At the time, I thought that this person was getting me to buy more or "up sell". Of course, I didn't listen and the hard reality was the counterperson was right. I had to go back and purchase more as the first coat was not thick enough to cover the old paint. What a waste of time.

Graphite lubricants are not so much different. A measurement of percent solids indicates the amount of graphite and other solid materials in the formulation after all of the liquid has been evaporated. Higher percent solids number will mean that you potentially have to run to the store less often than the others of lower percent solids.

graphite pencil and particlesWhat kind of graphite is it?

Graphite is much more than just what is in your No. 2 pencil. It is mined thoughout the world and it can be extremely expensive depending on the type of graphite and its purity. For example, vein and flake type graphites are the most lubricious grades compared to amorphous and synthetic graphites. In general, more lubricious grades of graphites are typically more expensive. Also, manufacturers can further process these grades of graphite to be more resilient and lubricious.

So, just because there are high percent solids, it doesn't necessarily mean that it is a higher grade of graphite or even if it is all graphite. Inert additives can make the product seem like there is more when it is still really lacking the anti-friction property of graphite. The best way to tell the difference is to look at the product performance.

Failed Water Resistance TestAnother factor that governs graphite coating performance is the type and amount of binder. The binder is the "glue" that allows the graphite to stick to the surface and to itself. Finding the right balance is important as it could mean poor performance. Too little binder would simply allow the graphite to blow off allowing rust to occur where too much binder might hinder the lubricity.

Sample Friction Test of Graphite LubricantsThere are several tests that laboratories use to evaluate the performance characteristics of graphitic coatings as recognized by the ASTM (American Society for Testing and Materials). The choice of graphite materials with its coating formulation will dictate the effectiveness and long-lasting nature of the lubricant. A water resistance test looks at signs of rust corrosion after three (3) days; this is a pass/fail test. A crosshatch adhesion test looks at the strength of the graphite coating material sticking to a metal surface. A score of 5B is good adhesion and 1B is poor. The water and solvent rub tests evaluate the durability of the graphite coating before bare metal is visible. Lastly, a friction test under a heavy load of friction determines the "slipperiness" of the material before the material is worn and the coating fails. The best graphite dry lubricant would be the one with the highest marks in these tests and therefore would imply how well it would work in your application. Below is a table that summarizes laboratory performance testing on dry film graphite products.

Dry Film Graphite Aerosol Lubricants Performance Testing

Product Brand Net Weight % Solids H2O Resistance Water Rub (50 max)1 Solvent Rub (50 max)2 Xhatch Adhesion3 Friction test @ 22500 psi4
A 5.5 oz 1.8% Fail 1 1 1B 1400 sec
B 10 oz 0.9% Fail 50 1 5B 1300 sec
B 10 oz 1.5% Fail 1 1 1B N/A
D 10.5 oz 0.7% Pass 1 1 5B 1000 sec
E 10.5 oz 0.8% Fail 1 1 1B N/A
F 11 oz 25.2% Pass 50 6 5B 700 sec
G 12 oz 1.6% Fail 50 2 1B 1750 sec
H 12 oz 41.9% Pass 50 50 5B 1250 sec
SLIP Plate® 12 oz 21.4% Pass 50 22 5B 2400 sec

1 ASTM D4752
2 ASTM D4752
3 ASTM D3359
4 ASTM G99 - Estimated force based on test surface area on all products

Conclusions
There is usually a reason why some products, seemingly identical, can have a vast difference in price. As the saying goes, "You get what you pay for". The value of the product and the caliber of its performance are dependent on the quantity and the quality of the materials. This definitely holds true for graphite dry lubricants. Next time you purchase a graphite lubricant, take time to ask: "Which product is really the best? What's really in my can?" Without the knowing facts, everything looks the same when it really is not.

Barry Lee is a product manager for Superior Graphite and responsible for the SLIP Plate product line. SLIP Plate branded products are the original, premium dry film graphite lubricants trusted for almost 40 years in commercial, industrial, and household applications. For over 95 years, Superior Graphite specializes in thermal purification, advanced sizing, blending, and coating technologies, providing value added graphite and carbon-based solutions globally.



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