Johnny Joint grease—an experiment
- Thread starter Mike_H
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From what I'm picking up CV2 is a calcium sulfonate thickener, and a synthetic base oil, while the Megaplex/Rockjock is a lithium complex in a mineral oil base. That didn't initially tell me anything so I had to do some reading. Neither are clearly superior but it sounds like LC might be better on high temperature and high shear, while the CS is more compatible with other materials and greased and more resistant to oxidation.
Originally that may have come from me. RJ has not always sold grease. I never like how difficult the bolt balls were to turn in the races so I started checking any grease I could get my hands on to see what had less breakaway torque. The CV-2 had the lowest and we had no issues with it staying in the joint, still don't. At the time I was not aware of the detrimental effects of the clay based soils on sucking out the lube.
OP
I currently have Johnny joints with CV2, Megaplex XD5 #2, and SuperLube silicone w/ PTFE, so I'll continue to follow it, but I'm settling on the reality that it's not going to matter what grease we use - if we can't get fresh grease to flow in through the zerk, we're going to be disassembling and greasing when the initial load of grease reaches the end of its life.
What's leading me to that is the research I've been doing suggests that dynamic bleeding out the oil is the unavoidable result of a feature, rather than a bug. It's part of the grease doing what it needs to do, but unfortunately, contamination accelerates it.
https://www.machinerylubrication.com/Read/28517/grease-dry-out-causes
This one goes into more depth and claims that thinner grades separate faster...though I'm still tempted to try a #1 or a #0 because even if I have to grease it more often, if I can get it into the joint instead of having to take the joint apart, I'll do it as often as I need to.
https://www.machinerylubrication.com/Read/28761/storing-grease-to-avoid-bleed-separation-
This research paper seems to demonstrate that the bleed rate doesn't change as the grease wears, and it compares a couple of "Lithium" greases and a calcium sulfonate grease, showing that the CS grease had a lower bleed rate. However, I know just enough to get an idea of what I don't know, and one thing I don't know is whether the thickener type actually influences the bleed rate or if the difference is due to other factors like thickener concentration, etc.
https://www.sciencedirect.com/science/article/pii/S0301679X22007253
Similar data was difficult to find in any official capacity when it came to silicone greases, but I did find a reference in a gun forum about silicone lubricants separating and leaving the thickener in the barrel and being very difficult to remove. My experience seemed to agree...the joints I lubed with the Energy Suspension stuff were bone dry with sticky, very difficult to remove deposits, and what little grease was left was like hot glue just before it completely solidifies.
What we know is the lube is going to go away and leave the thickener/carrier behind. If what is left behind provides lubricity, that is better than what we have now.
I wish i knew more chemistry so I could answer that question, but I don't. They use a lot of terms like "soap" to describe thickeners (though calcium sulfonate is categorized as a non-soap thickener), and I think slippery when I hear soap, but I don't know if it's still slippery when the base is gone. The bar of Dove in my shower doesn't seem terribly slippery when it hasn't been used all week.
Still lubricating when dry is what I was after with the SuperLube w/ PTFE but the properties of silicone grease when it's lost its base may be a deal breaker. I'm sure the PTFE helps, but the stickiness of the thickener probably negates it's impact.
That is one of the reasons you see moly greases recommended as they leave the moly behind as a secondary lubricant.
I wish i knew more chemistry so I could answer that question, but I don't. They use a lot of terms like "soap" to describe thickeners (though calcium sulfonate is categorized as a non-soap thickener), and I think slippery when I hear soap, but I don't know if it's still slippery when the base is gone. The bar of Dove in my shower doesn't seem terribly slippery when it hasn't been used all week.
Still lubricating when dry is what I was after with the SuperLube w/ PTFE but the properties of silicone grease when it's lost its base may be a deal breaker. I'm sure the PTFE helps, but the stickiness of the thickener probably negates it's impact.
What is the material of the ball in the joint? Could have it PTFE coated.
I'm starting to think that may need more pressure to actually work, like enough to push the thickener out of the way, the kind of pressure you'd have in a rolling element bearing.
Some form of carbon steel, so I'm sure it could be coated. I think @Mike_H was thinking about coatings at some point and I think he has closer resources to pull it off. I was gonna let him be the guinea pig on that one.
Some form of carbon steel, so I'm sure it could be coated. I think @Mike_H was thinking about coatings at some point and I think he has closer resources to pull it off. I was gonna let him be the guinea pig on that one.
In that case, Mike should have the joint and the ball PTFE coated and see how much of a difference it makes when things dry out.
OP
I'm starting to think that may need more pressure to actually work, like enough to push the thickener out of the way, the kind of pressure you'd have in a rolling element bearing.
Some form of carbon steel, so I'm sure it could be coated. I think @Mike_H was thinking about coatings at some point and I think he has closer resources to pull it off. I was gonna let him be the guinea pig on that one.
I did investigate having one of my coating suppliers (Oerlikon) coat the balls. Once I told him the use case he kinda laughed at me and said, “Good luck!”
So that is probably a no go. I have had the thought, off and on, of making a set of joints out of 400 series stainless and harden it to around 50Rc. That would keep the dirt from impinging on the ball and keep them a little less rust prone. Doesn’t solve the lube problem though, which is why I haven’t pulled the trigger.
I wonder if any of these coatings would be worth looking into? https://www.microsurfacecorp.com/amp/Low-Friction-Dry-Lubrication-Coatings.html
Or do we need to go more aggressive and look at something like TiN https://www.tincoat.net/coatings-offered/tin-titanium-nitride/
Or do we need to go more aggressive and look at something like TiN https://www.tincoat.net/coatings-offered/tin-titanium-nitride/
How about a "non-caloric, silicon-based lubricant"?
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OP
TiN is one of the things I talked to the guy I know. It’s a very thin coating (like 2 or 3 microns), applied how Oerlikon does it (PVD) It’s very hard, and it more to resist wear than to add lubricity.
There is another coating technology (CVD) that can build TiN thicker, like 7-8 microns.
Never thought I'd see semicon industry terminology (TiN and PVD/CVD) on this thread. Come on you guys, I hear those at work on an hourly basis and I come here to take a break from that madness
Never thought I'd see semicon industry terminology (TiN and PVD/CVD) on this thread. Come on you guys, I hear those at work on an hourly basis and I come here to take a break from that madness
TiN is very common in the machining world as well. Common coating on cutting and shaping tools.
OP
Never thought I'd see semicon industry terminology (TiN and PVD/CVD) on this thread. Come on you guys, I hear those at work on an hourly basis and I come here to take a break from that madness
Fully 75% of the parts we make at my shop go for some sort of coating. As @Blackjack said, its VERY common on cutting tools. TiN has given way to AlTiN now, mostly.
TiN and TaN (Tantalum Nitride) in various compositions are used extensively in the semiconductor industry. Though the thickness we work with are in the Angstrom/Nanometer range.
So between coffee and lunch breaks I read all 14 pages of this thread.
Seems to me the answer that I need to disassemble and lubricant these JJ every 6-12 months
Has anyone gone the direction of RK or Clayton joints?
Seems to me the answer that I need to disassemble and lubricant these JJ every 6-12 months
Has anyone gone the direction of RK or Clayton joints?