Combatting track oxidation in humid atmospheres

[Greg Elmassian]

we did the mass spectrometer test in G scale on the black stuff you can wipe with your finger. It was copper and zinc oxidized. (brass)...

there are very few real conductive greases, and you normally wind up getting it everywhere and shorting across the insulator from the axle to the wheel.

no matter what lubricant you put on the rail head, as long as it is not really thick, the small contact area of a wheel also means that the pressure per square inch there is enough to push through the lubricant to make metal to metal and conduct.

the whole trick is a film of something that keeps air, and thus oxidation from the top of the rail.

different environments, usually mostly related to ambient humidity seem to make different liquids work better for some people. ATF, wahl clipper "oil", kerosene, No-ox id (special A is the best one), Deoxit (my favorite) and others all do the same thing.

graphite is actually conductive and seems to also block oxidation

Greg

[peteski]

no matter what lubricant you put on the rail head, as long as it is not really thick, the small contact area of a wheel also means that the pressure per square inch there is enough to push through the lubricant to make metal to metal and conduct.

The only problem with this is that oily substances attract dust which can eventually build up thick enough on the railhead to prevent the wheel from reliably contacting the track. Then that crud can also stick to wheel treads (especially plastic wheels). So you have to clean the track and wheels. But other than that, yes a thin oily film will prevent oxidation of metal.  I'm not saying that this is a bad method for making model trains run reliably, but it is not a perfect solution.

[Steveruger45]

Great discussion guys.
Yes, I tried various oily stuff etc in the past but they have bad side effects, attracting crud/dust and all as you say Pete.
What I’m finding with the No ox id is that after you have applied it by  wipe on -let sit - wipe off ( you can do this in Karate Kid fashion if you like) it leaves a much drier surface. 

[Greg Elmassian]

I completely agree Peeteski, and avoided the accumulation issue, because people will swear it does not happen. Not wanting another argument, my experience is to keep the rails clean, or if you must put something on them, something very "thin" and you will still have to wipe clean and re-apply. In Z scale I have used Deoxit, has naptha as a carrier, and after that evaporates there's a very thin coating left.

In G scale I have SS rail, so no oxidation problems, clean with wet swiffers, great degreaser... works great on the black goo.

Greg

[Maletrain]

When dealing with alloys (like brass and nickel-silver), part of the chemistry under wet/humid conditions may be micro-circuits withing the metal surface, where small adjacent portions of different composition act like tiny batteries when exposed to the impure water "electrolyte".

Some anti-corrosion cocktails seem to try to get the tiny cracks and pits on the surface filled with a hydrocarbon insulator to prevent formation of these tiny circuits by eliminating the electrolyte from them.  The old, back woods trick of wiping down - then wiping off, new cars (both painted and chromed surfaces) with a mixture of paraffin and gasoline was one example, while the newer product, Boeshield (produced by Boeing for aircraft) is another.  That concept offers a potential for stopping track corrosion without having an oily (or waxy) layer on the part of the rail contacted by the wheels.  It might be what is occurring with the practice of rubbing recently cleaned rails with WD-40 to ******** oxidation, since WD-40 does displace water from cracks and pits before eventually evaporating away.

Another approach to stopping the corrosion action associated with surface cells in alloys is to chemically treat the surface to effectively neutralize the chemistry associated with the micro batteries, which is what I understand is involved with the "passivization" processes adopted for specific alloys.

So, I think there is probably a lot more involved in thinking about these track oxidation prevention techniques than just putting oil over metal.  And, adding the rolling electrical conduction issue, with applied voltage and potential sparking on the surface, may make things even more difficult to understand on a technical level.

[Doug G.]

All those "conductive" lubes are infused with "Graphite Clear".



Doug