Improving conductivity and reliability with... a pencil

Basic electrical and electronics, such as DC/Analog control.
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minipix
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Improving conductivity and reliability with... a pencil

Postby minipix » Thu Aug 13, 2020 1:51 pm

The Problem

I'll come clean - my track is far from perfect. It's all at least 30 years old, and second hand. It's not all the same brand, or made from the same metal. Some of it is scratched and pitted. I've got curves on an incline. My soldering skills were almost nonexistent when I started, so there's only the bare minimum of droppers, and rail joiners are relied on for transmitting current. I'm using Hornby insulfrog points. All my curves are radius 1. Put all that together and it's really no wonder that some of my locos have been hesitant at slow speeds. No amount of cleaning seems to have improved things, and every start and stop is accompanied with the uncertainty of whether it'll stall and need a poke.

The Solution?

While searching for ideas on how to clean my wheels and track, I came across people raving about using graphite sticks to solve all their conductivity problems. It sounded like an old wives' tale to me. But enough people swore by it that I figured I had nothing to lose by trying it. There were warnings about loss of traction, though.

The Science

Graphite turns out to be an excellent conductor of heat and electricity, even in small quantities. In fact it's often used in motors. And because of its hexagonal molecular structure, graphite slides easily across other graphite molecules, making it an excellent dry lubricant. Graphite is found in artists' materials and pencils, in various ratios of graphite to clay (which binds it together); a 2H would have a higher clay content, while a 2B would have more graphite.

The Application

People had said they used artists' graphite sticks, which would last years. I didn't have any, but I did happen to have a 4B pencil in my stationery cupboard. So I popped out to the layout and started scribbling on my rails. I couldn't see anything rubbing onto the track, so I wondered if perhaps my pencil wasn't as effective as a graphite stick. I remembered people saying not to use too much, as the locos would spread it around, so I just focused on the known problem areas, such as around the station and on the points.

The Result

Within minutes of sending my first loco onto the track it was clear something had changed. In fact, I'd call it "transformational". Utterly silky smooth, even at an imperceptible crawl. Suddenly my dodgy track was no problem at all, and my locos behaved beautifully and reliably. I was honestly surprised that such an easy - and free - solution had made such a dramatic impact.

The Down Side

Sure enough, as I ran the locos around the layout the graphite was spread around the rest of the track. At which point I realised that none of my locos would go up my little hill any more. It's only a rise of a couple of centimetres, but they all baulked at the first sign of an incline, as if they were dancing on ice. Turns out that loss of traction was more than I had expected. I ran my finger across the top of the rails, and it came up black. I thought I had been conservative in my use of my 4B pencil, but I've now spent a couple of hours rubbing and cleaning it back off the rails to try to regain a balance of conductivity and adhesion.

The Conclusion

Graphite is not a myth. It really does work. If you are looking to improve your conductivity, definitely grab your pencil. But use it sparingly - I thought I'd hardly used any, when actually I'd used far too much. If traction is important for your layout, maybe this isn't the solution for you. Otherwise, as long as you're careful, I would definitely recommend it. I'm sure the more experienced of you already know all about this, but I thought I'd share my adventure for anyone else who had never considered drawing on their rails!
Frontington & Backwoods Railway: https://www.matthewdawkins.co.uk/catego ... way-build/
LocoSound - sound effects for DC model railways: https://mafu-d.github.io/loco-sound

Dad-1
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Re: Improving conductivity and reliability with... a pencil

Postby Dad-1 » Thu Aug 13, 2020 3:08 pm

Been doing it for years, and discussed on here, although I tend not to put much
on the tracks. The weak point is wheel to wiper, so I rub the pencil along the
clean like left by the pick-up wiper.
Just one of those old tricks that work well under the right circumstances.
Still clean your pick-up wipers and wheel backs from time to time.

Like you I use a quality pencil somewhere between 'B' & anything softer.

Geoff T.
Remember ... I know nothing about railways.
viewtopic.php?f=22&t=32187 and Another on viewtopic.php?f=22&t=28436&start=60&st=0&sk=t&sd=a

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Bufferstop
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Re: Improving conductivity and reliability with... a pencil

Postby Bufferstop » Thu Aug 13, 2020 8:37 pm

Back in the 1980s PC hard drives were the size of a shoe box and often the spindle protruded through their base and a big brass spring strip earthed it. Whatever lubrication was on that spindle it didn't last long then an ear splitting screech would develop. A 4B pencil was always the answer. Those who had to share their workspace with these monsters couldn't believe the answer was so simple.
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Re: Improving conductivity and reliability with... a pencil

Postby Ironduke » Thu Aug 13, 2020 11:20 pm

Most pencils have some clay as well as graphite. The B indicates the proportion of graphite and clay. The higher the B number, the more graphite.
According to this https://www.qcaa.qld.edu.au/downloads/s ... aphite.pdf even a 9B pencil still has some clay in it. I've never seen a pencil blacker than 6B at the shops.
Regards
Rob

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Re: Improving conductivity and reliability with... a pencil

Postby simplealec » Mon Sep 21, 2020 4:06 pm

I have a simple shelf layout (it's just an oval going around the walls, with a couple of passing loops) with wide-radius curves and no inclines.

Does this sound like a good fit for testing this graphite method? I'm assuming you can buy graphite sticks from an art supplies shop... or at least a soft pencil. If the worst I'll get is some wheel slip on longer trains, that if anything sounds prototypical. I'm keen to try this!

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minipix
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Re: Improving conductivity and reliability with... a pencil

Postby minipix » Mon Sep 21, 2020 4:26 pm

Sounds like an ideal sort of layout for this technique. Yes, any art supply shop should sell something appropriate. Failing that, online. And if you do find that you're getting too much slippage, just clean your tracks and the graphite will come straight back off again.
Frontington & Backwoods Railway: https://www.matthewdawkins.co.uk/catego ... way-build/
LocoSound - sound effects for DC model railways: https://mafu-d.github.io/loco-sound

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End2end
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Re: Improving conductivity and reliability with... a pencil

Postby End2end » Thu Feb 04, 2021 11:36 am

Would this help with dead frogs?

(If you didn't know track terminology this would seem like a really odd question!) :lol:
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minipix
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Re: Improving conductivity and reliability with... a pencil

Postby minipix » Thu Feb 04, 2021 12:24 pm

Interesting idea. You'd still need to power your frog (and connected track) to ensure the polarity is always right, and that might require a bit of work as insulfrog points are connected up assuming the frog will be dead. It's probably possible, but you'd need to get the wiring right otherwise you'd get short circuits. And the graphite will eventually wear off too. Basically, I think graphite works well at improving conductivity, but I wouldn't rely on it as an alternative to metal!
Last edited by minipix on Thu Feb 04, 2021 3:33 pm, edited 1 time in total.
Frontington & Backwoods Railway: https://www.matthewdawkins.co.uk/catego ... way-build/
LocoSound - sound effects for DC model railways: https://mafu-d.github.io/loco-sound

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End2end
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Re: Improving conductivity and reliability with... a pencil

Postby End2end » Thu Feb 04, 2021 2:56 pm

minipix, did you add it to the wheel backs of loco's or just to the track?
Thanks
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minipix
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Re: Improving conductivity and reliability with... a pencil

Postby minipix » Thu Feb 04, 2021 3:32 pm

Yes, adding a little graphite to the wheel backs supposedly aids conductivity from the wheel to the pickup. I run little tank engines, so I need all the electrical assistance I can!
Frontington & Backwoods Railway: https://www.matthewdawkins.co.uk/catego ... way-build/
LocoSound - sound effects for DC model railways: https://mafu-d.github.io/loco-sound

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Mountain
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Re: Improving conductivity and reliability with... a pencil

Postby Mountain » Thu Feb 04, 2021 3:42 pm

Adding weight also helps a little.

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Bufferstop
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Re: Improving conductivity and reliability with... a pencil

Postby Bufferstop » Thu Feb 04, 2021 4:30 pm

minipix wrote: ................as insulfrog points are connected up assuming the frog will be dead.........................

As long as you fit insulating joiners to the V rails Treating them as though they are electrofrog will work, but you won't get the benefit of a metal frog, ie. an unbroken conductive path through the crossing. Peco insulfrog and settrack have short non conductive parts Hornby settrack ones have quite a long dead section.

End2end wrote: Would this help with dead frogs?

Perhaps it was ingesting all that graphite which made them croak in the first place :evil:
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End2end
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Re: Improving conductivity and reliability with... a pencil

Postby End2end » Thu Feb 04, 2021 5:07 pm

Bufferstop wrote:Perhaps it was ingesting all that graphite which made them croak in the first place :evil:

:lol: :lol:

Thanks for the input members. I can confirm it's peco set track with insulated rail joiners and most rolling stock has extra added weight.
It's mainly the 0-4-0's (on dcc) that get stuck on the points sometimes causing them to go shooting off round the layout.
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jimread
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Re: Improving conductivity and reliability with... a pencil

Postby jimread » Tue Oct 05, 2021 3:54 pm

Hello all,

I use a blunt Carpenters pencil the lead in these is oblong and quite hard.

Model railway rail is extruded nickel silver, the extrusion dies can be made in two ways, spark eroding or wire eroding, The nature of machine tools being dependent on lead or ball screws and electric motors means that the minute vibrations produce micro grooves in the extrusion. Blown up on a shadow graph spark eroding looks like a ploughed field and wire eroding a harrowed one.

Sparking is a lot cheaper and is how rail dies are made. I use 600 grit wet and dry paper on my rail, wipe it with clean dry cotton and then use the carpenters pencil.

With the above in mind a hard lead makes sense. Worst case possible, a Triang/Hornby Nellie chassis, original clank clank motor. Stripped down to its individual parts, motor, wheels, axles and con rods, all cleaned in Jizer. Commutator filed flat, wheels polished both sides.

https://www.youtube.com/watch?v=MJOXNQWUxoc

Cheers - Jim

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Re: Improving conductivity and reliability with... a pencil

Postby 21C1 » Tue Oct 05, 2021 8:02 pm

What controller are you using?


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