Nickel plating - how to do it, how effective is it?

[mmagliaro]

I have reached a point with my 0-6-0 engine project where I really have to decide whether or not I'm going to
nickel plate the driver treads.  I have read a lot of on-line pieces about plating, either electroplating or "electroless" (chemical).
Caswell, Micro-Mark and a few others sell basic kits for doing this.

My thought was to take a driver with its half-axle, put the half axle into a plastic tube or something similar so I can hold it from above,
dip it in the solution, and plate away.  I don't know if I need to worry about the evenness of the coating.  I could
put the extension tube into the mill chuck and slowly rotate the wheel in solution, which ought to make thing really even.
But with plating thicknesses of well under .001", I doubt it really matters how perfectly uniform the thickness is.

Questions:
1. Have any of you actually used these plating kits, either electroless or electroplating, for nickel?  How well do they
work?  What problems should I look out for?

2. Will a nickel-plated driver conduct electricity better or worse than brass?  I *think* it will stay cleaner, or at least, the oxidation that forms on it might be more conductive than the oxidation that will form on brass, so plated drivers would be less trouble-prone for pickup.  Is that really true?   Remember, this isn't going to be "nickel-silver".  It would just be plated with nickel.

(I am not concerned about hardness or wear.  The reality is that I will never put enough hours on this engine to wear out the drivers, even if they are just plain brass.)

Thank you for any wise insight you might have for me on this one.

[narrowminded]

I wish I could tell you with certainty but I can't... yet.   That's a huge part of the reason I'm building twenty-five prototypes of my chassis for final parallel testing.  I'll be testing nickel plating, electroless nickel on the chassis (bores to be plated), and in some specific areas, gold plating.  I may find I need all, some, or none.  For the wheel materials I'll be testing plain brass, nickel silver, and tungsten, also with the various platings as well as no plating.  And for cosmetic as well as conductivity... maybe... I'll try some parts with black nickel.  I've got a very good plating expert that I've relied on for thirty + years and we will be sitting down and going through all of this stuff, including the various platings, and he'll be doing my test units.  We've already had some conversations and he's committed.  But I'm probably months away on this. 

I've already done a TON of research on this and I don't really have any good answers.  I've got a LOT of the theory but one of the reasons there's little to be had is because the truth of the matter is, NONE of these materials we use in our hobby receive a real blessing for extremely low current service as we use them for our low speed starts and stops.  Phosphor bronze and beryllium copper are pretty good but still not industrial rated or industry blessed without plating.  Not at these milliamp draws and through what is basically an extremely low current slip ring. We get away with it and in what would be unacceptably short times in service for industry, we're content to accept those faults, no real harm done, and then maintenance the thing.  What we're doing and getting away with at some level really just isn't the proper way to do it reliably and it's why a few hundred hours, trouble free, we consider to be good.  It's also why all of the searches in the world won't get you the answer to what's the best plain metal pick up for low current slip rings.  It's because there really isn't one.    Sooo... we add weight and blow through it.    (Except I don't have anywhere to hide more weight when my whole loco isn't much bigger than a normal truck.)

Electroless nickel is only needed if you're trying to plate inside holes or the inside intersection of sharp corners.  Standard electroplating won't make it into those areas.  A quick search will get you a good explanation of that.  Nickel tends to be harder but so is its oxide.  Will it work and will the wheel or axle movement break through that oxide better than the plain phosphor bronze or any of the other materials?  At the few milliamps a good slow start likes?  I wish I knew.  And in the not so distant future, I will.    As it is, I got pretty good service with a few configuations of just phosphor bronze.  Especially when it was run a lot every day.  I worry about the one that sits a few months between services.

The plating kits should work fine if you follow the directions carefully.  You might check if your soldered joints will be an issue with or for the plating.  If they are, you could probably pen plate just the spots that you want.  That may be the way for you to go anyway.  And you could get inside bores if they're small enough to get a pen/ brush tip in.  A big time plater would say it's too much labor but for a few pieces every now and then, it's no big deal and the equipment needed is pretty simple.  I may be trying that with hard gold in a few small areas on a part that will already be nickel plated (the hard oxide potential, just don't know for sure).  As I said, I'll be testing it all and will know some things.  Just not yet.  Sorry.

[Chris333]

Would blackening have the same effect, but look better?  A lot of the newer stuff is blackened and shiney. I think they use a hot process. What I don't know is if they are plated first and then blackened or if it is all done at one time.

[peteski]

I wish I knew what companies like Kato used for plating wheels. It looks good, seems to be conducting well, and it is fairly durable.

Except for the American Freedom Train GS-4 - they used different plating and it was a disaster (non-conductive). I had to remove it with a wire brush.

[narrowminded]

I am pretty sure that some I've seen are black nickel.  It gives some protection, is still conductive, but is primarily for cosmetics.

[mmagliaro]

I really like the look of the black nickel plating.  I was thinking about that too. 
Caswell sells Black "Krome" and Black Nickel "plug n plate" kits for about $37 - plenty cheap enough to try out.

http://www.caswellplating.com/plug-n-plater-black-nickel-kit.html
http://www.caswellplating.com/plug-n-plate-black-krome-kit.html

The photos of their black nickel look a little too translucent to me.  The black krome looks somewhat blacker, so I am thinking
of going with that one.

I could just use metal blackener, but that may not be as conductive as the nickel plating, and that's what concerns me.
A layer of oxidized brass is probably not a good choice.

The above systems are the really simple ones where you just clip the "-" to the part, and then the "+" is wand wrapped in gauze that you keep dipping in the solution and brushing over the part.  I think this will work, even for a wheel tread, because
as I said above, the plating layer is so thin that I don't have to worry about getting it non-uniform and making the wheel be
out of round.

narrowminded: I really appreciate all of your thoughtful words on the subject.  Yes, I have been bulking up this engine with
all the weight I can get into it because in N Scale, weight is king.  These little engines can't track and can't pickup current
without sufficient weight on them.   At least I have an 8-wheel tender (yet to be built) which will really help with the pickup.
But I've been trying to get the engine to run well just on its own with only 4 drivers for pickup (the other 2 have traction tires).
It can run pretty good now, but I don't want to compromise any pickup with a blackener if I can help it.

[narrowminded]

I really like the look of the black nickel plating.  I was thinking about that too. 
Caswell sells Black "Krome" and Black Nickel "plug n plate" kits for about $37 - plenty cheap enough to try out.

http://www.caswellplating.com/plug-n-plater-black-nickel-kit.html
http://www.caswellplating.com/plug-n-plate-black-krome-kit.html

The photos of their black nickel look a little too translucent to me.  The black krome looks somewhat blacker, so I am thinking
of going with that one.

I could just use metal blackener, but that may not be as conductive as the nickel plating, and that's what concerns me.
A layer of oxidized brass is probably not a good choice.

The above systems are the really simple ones where you just clip the "-" to the part, and then the "+" is wand wrapped in gauze that you keep dipping in the solution and brushing over the part.  I think this will work, even for a wheel tread, because
as I said above, the plating layer is so thin that I don't have to worry about getting it non-uniform and making the wheel be
out of round.

narrowminded: I really appreciate all of your thoughtful words on the subject.  Yes, I have been bulking up this engine with
all the weight I can get into it because in N Scale, weight is king.  These little engines can't track and can't pickup current
without sufficient weight on them.   At least I have an 8-wheel tender (yet to be built) which will really help with the pickup.
But I've been trying to get the engine to run well just on its own with only 4 drivers for pickup (the other 2 have traction tires).
It can run pretty good now, but I don't want to compromise any pickup with a blackener if I can help it.

Yes, black nickel would be the safe way to go, I think.   You can build it up by how long you plate it so that might just be a case of a little more time.  It does tend to be translucent but as I've seen it, it remains attractive and doesn't lose that industrial machine look.  That's also very subjective and full of "a lots" and "a littles", not very exact terms. 

Also, instead of the swab there is a plating pen made that has a wick that's not unlike a Sharpie point.  It can be shaped/ sharpened a bit, too.  That might be a little easier to use and control than a wrapped up swab, especially for small detail areas.  A search should find it.  Don't remember if Caswell had such a thing or not. 

Edit add: Chrome has a very hard oxide which is how it works if you want shiney or good wear properties.  Might not be so good if you're trying to maintain conductivity.  Probably why it's not used for contacts.  It has a lot going for it but electrical conductivity isn't one of them.

[mmagliaro]

Caswell does sell those pens too.  I don't think one comes in the kit.

I decided to go with black nickel after all.  I called them on the phone and asked them what exactly the "black krome" was plating onto the surface and he said he couldn't tell me because it was proprietary.   So forget that.
Nickel it is.  At least then I know it's nickel.

I am only plating the wheel tread and flange.  The wheel center and spokes will get painted black.  So I don't think I'll have much trouble getting coverage on the rim with the gauze thingy.   

The half-axle is already mounted into these drivers.  So I am planning to just clip
one lead to the axle on the back to hold it, and then keep dipping the wand and going round and round the wheel until I get some decent dark looking plating on it.

(and I have some spare throw-away rims I will test it on first before I use it on one of my precious 6 actual drivers)

[narrowminded]

I suspect you'll be good.  Read up on it, follow the directions carefully, and have fun! 

[Doc Frankenfield]

I have had a good deal of success with the casswell product. in fact I had cold plated resin with copper powder and plated that..

[mmagliaro]

Well, I plated the drivers with Caswell's "black nickel".

It was easy to do, worked well, and looks good.  However...

While the plating isn't thick enough to worry about inconsistencies introducing any wheel wobble, one thing I had not counted on was that the black nickel coating isn't nearly as conductive as brass.  And worse, it isn't consistencly electrically conductive.
I spent two days trying to figure out how I had introduced some sort of mechanical binding in my mechanism, until I
jumpered a Kato Mikado tender behind the engine and it smoothed right out.  The plating's conductivity isn't uniform,
so it is causing massive weird speed-up/slow-down in the operation.  And I don't want to just count on the tender for
my electrical pickup.  I really want these drivers to work.

I already spun the drivers and polished them with the polishing compound, which helped. But I think I'm going to do it some more to see if I can make it better.  Polishing them once at least got the engine to run and got it a lot more speed.
(I was getting some serious voltage drop through the nickel plating!)

[mmagliaro]

Take 2.
Spun the drivers, took off the plating, then replated them.  But this time, I just ran the wand around the wheel a few times, just enough for it to darken, and STOPPED.  (The first time, I continued this process for 2 minutes on each wheel).

Then I washed the wheel off, and spun it against some paper towel.  I got a much smoother finish that is
more a dark metallic (Neolube) sort of color - which is more what I was hoping for anyway, rather than jet black like they were.

They do conduct much better.  Not great, but a lot better.  They are a lot like that black coating that is on Kato Mikado
drivers, which I have found has a pretty high resistance (upward of 30 ohms!).  I'm still not sure I want to leave it on there,
even though it looks good.  The bare brass ran so much better.

[Chris333]

So is that the difference between nickle and nickle-silver 

[peteski]

All Kato locos have plated wheels (some dark metallic plating) and they all run well. Except for the American Freedom Train GS-4 which had different type of non-conductive plating on the drivers.

[mmagliaro]

Even the later-generation Mikados that don't have the bronze strip problem
in the drivers still have a tread resistance often as high as 30 ohms from that black plating. 

At 150 mA, that will drop 4.5 volts.  Allowing for
2 or 3 drivers all conducting at once, it might only drop a volt or 2.   (And since it's getting power from the tender
99% of the time, you'll never notice it).   If you polish off that plating and try it,
the increase in speed at a given voltage is very noticeable (if you run the engine without the tender, that is).

More importantly, the Mikado plating is dead-even and uniform, something I can't really do at home with a
stone-knives-and-bear-skins plating kit.  So even though there is voltage drop through that plating,
it doesn't really matter because it's consistent.

Mine, ahem... is unfortunately not that consistent.    It may LOOK like the plating on the Mikado, but it's clearly not as good.

---------------
Chris,
This plating is nickel.   

Nickel-silver is actually an alloy of nickel and copper, so it's more conductive than plain nickel, and less conductive than
copper (or brass).  It would be great if somebody made a nickel-silver plating solution, but I don't know of one.
It does make me wonder if I could mix the nickel plating solution + the copper plating solution and actually have that work.
But something tells me it can't possible be that easy.

I have sent Caswell an inquiry about this to see what they have to say.