Author Topic: Advanced coatings  (Read 592 times)

Alan

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Advanced coatings
« on: June 21, 2018, 07:29:24 AM »
As some of you know, I grew up in a sporting goods store in the Kansas City, area, owned by my parents. My mother looked after the store, as my father worked for the State of Kansas as State Engineer, out of the Architectural Division. During the war years (WWII), he worked as plant engineer for Pratt-Whitney’s radial engine manufacturing facility. I mention all of this, because it gives the reader a bit of understanding about my father, and the subject at hand.

My father was many things, from stern-minded, mean at times, and a striver to learn new technologies. It was this latter part which was sort of passed on to yours truly. Two related facets of his curiosity, centered around the use of molybdenum disulfide.

Molybdenum disulfide (MoS2), moly for short, occurs in nature as a mineral (molybdenite). Moly is a very slick compound, hence its use in lubricants. In fact, is is somewhat slicker than graphite, and tends to adhere better to metallic surfaces than graphite. It is no wonder then, that it was used abundantly in the aircraft industry.

Fast forward a bit, my father started playing with moly as a lubricant for trigger assemblies (think sporting goods store). In fact, it is amazing how it effects the feel of a trigger if properly applied. He also used it to coat bullets, but with limited success as my father never reloaded ammunition. What’s fascinating, my father was doing this sort of experimenting, 30 years before it became a fad in the late 70s. Which, incidentally, is when I got interested in coating bullets.

To be sure, there have been other lubricants used to coat bullets, and a quick Google search will garner hundreds of pages of data. Of note is the use of both Hex-Boron Nitride (HBN) and Tungsten Disulfide (WS2). These lubricant powders are many times slicker than graphite, and hold up better under high heat. But it is the latter, I want to cover.

Tungsten Disulfide is better known under its trade name, DanZac. It was widely sold during the 70s and 80s for lubricating bullets. This fact prolonged barrel life of high-velocity cartridges, but as better barrel steel, rifle powders, and bullets became available, it fell out of use. Today, it is hard to find except in large quantities. However, it is still sold as a lubricant for Pinewood Derby cars. (https://www.ebay.com/itm/Tungsten-Disulfide-WS2-Powder-Pinewood-Derby-Dust-bullet-lube-5-Grams/283010155378?hash=item41e4b84372:g:P48AAOSwmgJY5qst)

I haven’t thought too much about using it to lube pellets, as lead by itself is a fairly good lubricant. It is also rather messy, and once coated, removing the excess from pellets would be an arduous undertaking. However, one place it shines, is lubricating hammers, bolts, an other hard-working parts of modern airguns. And here is what I found!

The tuned velocity of my .25 caliber Cobra, shooting 25.39 grain JSB pellets, hovers around 870 FPS. I cleaned the inside of the action and the hammer, to clear off any remaining graphite. I re-lubricated the surfaces with DanZac. Nothing else was done. The average velocity increased to 880 FPS. That is too great a difference to say it was a change in ambient conditions.

The other factor, which is just as important, is the ease of cocking. I didn’t measure it, but it sure feels lighter. And, I don’t suspect DanZac will wear off as quickly as graphite.

Enough said.


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Alan

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steveoh

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Re: Advanced coatings
« Reply #1 on: June 21, 2018, 11:46:18 AM »
This is really great Alan. I will buy a bottle and feed my Sumatra with it's gritty trigger. :)
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Tinkerer

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Re: Advanced coatings
« Reply #2 on: June 21, 2018, 11:58:03 AM »
Very interesting!  I think I'm going to try some myself.  Thanks for the info!

Glen

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Re: Advanced coatings
« Reply #3 on: June 21, 2018, 07:03:01 PM »
I just bought some to try.

bnowlin

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Re: Advanced coatings
« Reply #4 on: June 23, 2018, 01:06:55 PM »
I got an ounce coming we'll see.
Bobn