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Discussion Starter #1
Anybody here that has added resistors to your wheel sets? Any suggestions you can offer from your experience?

My intention is to add a 10k ohm resister to one axle of every freight car I own. I know this will be time consuming but if I can do a few each day it will be a bit les daunting.

Thanks in advance.
 

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I put resistors on each end axle (so 2 axles per car). I figured that would protect a car that was only partially within the block. I used small surface mount resistors, which are fairly cheap. I also chose 10k ohm resistors. You’ll also need some conductive paint to make a good circuit connection between wheels through the resistor. The paint also acts as an adhesive to keep the resistors in place. Be sure to test conductivity with a meter after everything has dried. You may occasionally have either shorts or open circuits that you’ll need to fix. I did a batch of about 12 axles at a time. It’s not hard, but is a bit tedious.
 

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I found a resistance paint. Much easier than putting resistors on axels. Just paint it on touching each wheel, let it dry and its good. Don't recall the name though.
 

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Discussion Starter #5
Mark, Never mind I spotted a YouTube video that explains the whole process.

Thanks for your help.
 

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How does resistance paint work? Any conductive paint I've seen has a specific resistance per volume, so you would end up with a different resistance depending on how many layers you put on, and how thick each layer was. I just don't see how you could get each wheel set to be a specific resistance?
 

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If you are looking for a specific resistance then use a resistor. The paint provides about 10K ohms of resistance for a single layer of paint. The actual amount of resistance might vary from axle to axle, but then are you going to only run a certain number of freight cars to maintain a certain total resistance for the whole train?
I just painted it onto one axle of about 100 or so freight cars then put em back on the track. I don't even know which ones they are now as they have been reshuffled with the rest of the rolling stock many times over the years.
 

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OK so this must be different from 'conductive' paint? I'm using Kadee wheels which have a plastic axle, so this could be very helpful. I haven't been able to find anything with that description though, any chance you could provide some more info to help locate the product?
 

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if you want to hold a relatively tight tolerance on the value, you may have to go with resistors, either standard or smd as you choose .. with conductive paint

for 'looser' tolerances you can use resistive paint by itself ..
check ebay for 'conductive paint' and 'resistance paint'
note: most conductive paint has high percentages of silver, and is quite expensive, but lower in cost than screwing up an axle with a soldering gun, lol
 

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Unfortunately ebay was the first place I checked for resistance paint. I've got wear-resistant, water-resistant, mildrew-resistant, rust-resistant... Sorry, I'm not having any luck, that's why I asked.

Conductive paint is easy to find, in fact I probably have some kicking around somewhere. (if it hasn't dried up). Hmm that reminds me of another trick, using conductive paint to attach the resistor rather than trying to solder it. I already have a strip of 10k SMD resistors, might as well give that method a shot.
 

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Discussion Starter #13
the 1206 size would be easier to handle, but if you're eyes are good ... ?
My eyes are 73 years old. So I want to find the dimensions of the "1206" size. Could not find on the Digi site. Do you have a link?
 

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I was actually going to suggest 0603 or 0805 SMD resistors, but those are probably going to be TOO microscopic for a lot of people. :)

If I remember right, the numbers represent the dimensions in hundredths of an inch. So 1206 would be 0.12 x 0.06, and 0603 would be 0.06 x 0.03.
[Edit] Verified, here's a link providing dimensions.
 

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The datasheet for the resistor in the link you listed has the dimensions at 1.6mm x 0.8mm.

Hope your SMD skills are up to speed. That is a very tiny component.
 

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Discussion Starter #20
Guys, Thanks for all your help. Right now I am leaning toward the 2512 which is 1/4" x 1/8". That will be the easiest to handle and work with. One sneeze and all the others would be GONE!!!

Code........Length........Width........Height........Power
Imperia......inch...........inch...........inch..........Watt

0603.........0.024.........0.012..........0.3..........0.25

1206..........0.12..........0.06............0.022......0.25

2512.........0.25............0.12.........0.024.....1
 
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