# What is a "conductive lubricant" and why do I care?



## Greg Elmassian (Jan 3, 2008)

There's a thread on another forum that brings up a good FAQ that bears repeating, and actually has information for newbies and experienced modellers alike. 

So here goes another "Techno-Greg" thread. 

I think at one time or another we have all heard of a "conductive lubricant". Wow, that sounds great! 

It seems to make sense that if you have power pickup on an axle, a lubricant that was ALSO conductive would be a great thing. Well it COULD be. 

*First: let's talk about what is REALLY conductive or not.* 

In the model train industry, I only know of ONE product that is plastic compatible and says "conductive" on the outside. That's LGB "conductive paste" in the red and white tube. 

This stuff is NOT conductive. I don't care what the tube says. Put an ohmmeter in it. Yes I know it has graphite in it. But it's not solid graphite, but little particles in suspension in a nice grease. Not conductive. Period. 

There are other "conductive" products, that are NOT plastic compatible. Aristo has one called "Electra Lube". It's actually somewhat conductive, not enough to help anything (more later), but it is documented to destroy certain plastics, notably the first generation of Aristo truck sideframes: //www.aristocraft.com/vbulletinforums/showthread.php?t=5686 

There are "conductive lubricants" that are kind of a light oil/clear fluid. They are not conductive either, but it does not matter, they eat plastic, and say not for use on plastic. They are more like "tuner cleaner" in a light oil base. 

There are also real conductive lubricants with copper, silver, or gold in them. They are VERY expensive, and do conduct electricity. They are not normally plastic compatible. The danger here is they spread everywhere, so even if it did not attack the plastic sideframes, it has the potential to create short circuits on insulated wheel sets, and many other parts. Just not practical to use. (This stuff is often used in electrical wiring and large high current wipers in moving equipment). 

*Then why are people calling something conductive when it's not?* 

This is because the best thing you can do to keep metal surfaces conductive is to keep them from oxidizing. Just as oxidized brass rail does not conduct well, virually any oxidized metal surface does not conduct well. 

So, if you put grease in your LGB rail joiners before assembling, water and air cannot get in, and it keeps the joint conductive. Basically any grease will do. In the auto industry, when we had rotors and distributor caps, what grease was put on the contacts? Silicon grease. It's a wonderful dielectric, i.e. insulator, by itself. 

*But wait! how can this work, I put an insulating grease on my axles? How does the electricity get through?* 

This is the part you have to understand. It actually takes a VERY SMALL patch of "clean metal" to make electricity flow. On a round axle, the actual contact "patch" is very small, but on that very small part, the pressure is very high. High enough to make sure the metal parts touch. 

So all you need to do is keep the metal clean, unoxidized. 

*What's the bottom line?* 

Use the appropriate lubricant for your axle bearings, grease or oil, use grease on wipers or rail joiners. You can still use the contact cleaner and lube stuff on your motor commutators, but use it sparingly. 

The bottom line is the electricity WILL get through, just keep it clean and oxide-free. 

Regards, Greg


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## jimtyp (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

Thanks for the info Greg! I was wondering about that stuff myself. Makes sense now.


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## pdk (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

You read my mind. 

For example, I have long wondered why there isn't some conductive goop I can just slather on the poles of my wonky Tamiya battery pack connectors. 

Thanks for taking the time.


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## Greg Elmassian (Jan 3, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

The best thing on the connectors is probably a silicon grease, it would be clear and not messy if you got it on yourself, if I am understanding your type of connectors. 

Regards, Greg


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## markoles (Jan 2, 2008)

Maybe that's why my FA has been having problems running ever since I replaced the brass bushings. I dipped the axles in LGB 'conductive grease' and reassembled. I'll look in to that when I have a chance. 

Thanks, Greg.


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## Greg Elmassian (Jan 3, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

Should not hurt anything Mark, it's an OK grease. I prefer other greases though, like the hob-e-lube, and aero-locomotive greases... the hob-e-lube has moly in it, better than graphite in my opinion. 

Most of these "dark" greases are lithium based. 

Regards, Greg


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## Jerry Barnes (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

I've used a Silicon Dielectric compound that I got at an auto store. Use it all the time and it works great. Jerry


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## Greg Elmassian (Jan 3, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

My experience has been that the silicon dielectric grease is normally friendly to plastic, but it's lubricating qualities are not as good as "purpose designed" lubricating greases. I would not use it on high load lubricating tasks. It's more often used for insulating, keeping out moisture, and lubricating O rings like in filter housings. 

Regards, Greg


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## Paul Norton (Jan 8, 2008)

I tried the silicon grease from Active Electronics in the motor blocks of an Aristo-Craft FA-1. It quickly turned to oil when agitated or warmed and ran out. LGB grease seems to be somewhat similar when used on the worm and pinion gears in motor blocks. Labelle appears to be the only plastic compatible grease that will cling and not melt. 

The silicon grease is handy for lubricating the moving parts on side frames however. Even when wiped off the silicon seems to leave the plastic surfaces slippery. 

My pet peeve is the dirty black grease USA Trains uses in the bushings of their diesel truck bushings. It gets on your hands, clothes and anything else you touch. The first thing I do clean the axles and bushings, and add some clean white Labelle grease.


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## markoles (Jan 2, 2008)

Greg, 

I'm talking about I think I put that conductive Paste on the axle end that sticks in to the brass bushing. These are old style FA blocks. While being tortured last night (wife insists on watching Dancing with the Stars, and during the history channnels' Locomotives program, no less), I took the sideframes off, and cleaned the axle ends and brass bushings. The old style wheels are very dirty, and I might try Ron Wenger's method of using wire brushes to clean off the arced carbon deposits. A test after everything was put back together resulted in the continued poor performance I have been dealing with since about 3 years ago. I am really just biding my time until the new FA motor blocks are back in stock. Then I can add some weight to the FA-FB and get the performance like the RS-3. 

Mark


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## Skip (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

Some conductive lubricants contain a proportion of conductive salts dispersed in the lubricant, rather than metal particles. This is particularly true of the silicon based gelled conductive lubricants. I haven't found a need for conductive lubricants in my track powered setup and I've never found a lubricant that would inhibit current flow when applied in proper proportions. The concern with "non-conductive" greases is that they float the contact point off the contact surface due to their viscosity - the conductive component is supposed to bridge that. However, the frequent consequence is arcing and charring of the lubricant.


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## Jerry Barnes (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

I use the silicone on my track joiners, seems to help keep continuity over the years. Jerry


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## Mike O (Jan 2, 2008)

*RE: What is a "conductive lubricant" and why do I care?*

Greg, 

Thanks for the post. That is one of the things I have often wondered about, but never taken the time to acutally research. Very helpful. 

Mike


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