A source for replacement motor brushes!

[mmagliaro]

This comes up periodically (somebody hunting for replacement brushes for a motor), and I stumbled upon something that could be really useful.

https://www.graphitesupplies.com/Poco-EDM-C3_c_30.html

"Isomolded Copper Graphite Mini Rod"

What's that, you say?  It is graphite impregnated with copper.  When I discovered that one could actually buy sticks of this stuff in 12" or 18" lengths for under 10 bucks per stick, in almost any diameter of the rainbow (seriously, they sell it in .001" increments in any size you want), I thought, "MUST TRY THIS AS MOTOR BRUSHES"

I chose the EDM-C3 grade because they had it in convenient sizes, but also because from their descriptions of all the grades
on this page here:
https://www.saturnedm.com/edm-raw-materials-metal-graphite/
made EDM-C3 sound like the ideal thing for motor brushes.

I bought some in 3/32" and 2mm (.078").  I buzzed off two little pieces with a Dremel, stuck 'em in one of my Rivarossi motor rebuilds, and whaddya know?   It works!  Runs smooth, draws the same current.  I only tried it for 10 minutes or so, so this is certainly not a longevity test.

But maybe other folks would like to try it too, so I am passing this info along.
An it turns out that you can buy this stuff from a LOT of places.  Now that I know to look for Isomolded Copper Graphite Rod, it seems to be positively everywhere, even Amazon.

[peteski]

Thanks Max!  You always seem to find some interesting stuff out there to help out with model loco maintenance/repirs.  Do they also sell rectangular/square shape "rods"?  Some older models use that type of brushes.

[woodone]

Well time will tell. Sort of depends on the hardness/softness of the graphite. Like drafting pencils, you can get some very hard or soft leads in them. So I would keep a eye on them for brush or commutator wear.
Did you remove the copper clad around the graphite?

[mmagliaro]

Well time will tell. Sort of depends on the hardness/softness of the graphite. Like drafting pencils, you can get some very hard or soft leads in them. So I would keep a eye on them for brush or commutator wear.
Did you remove the copper clad around the graphite?

There is no cladding.  It looks exactly like motor brush material where you have a graphite brush with tiny flecks of copper scattered through it.  I just cut off a short stub about the same length as the existing motor brushes, stuck 'em in there, and the motor ran.  Yes, I need to test it running for a couple of hours and then see how the brushes and the comm look.

The actual description is:
"EDM-C3 is a high density graphite infiltrated with copper. Recommended where speed, wear, and surface finish are important. Unequalled for fragile electrodes"

[mmagliaro]

Thanks Max!  You always seem to find some interesting stuff out there to help out with model loco maintenance/repirs.  Do they also sell rectangular/square shape "rods"?  Some older models use that type of brushes.

I looked after you asked that and I cannot find anybody selling copper impregnated graphite rod in anything but a round shape. There are sheets of the stuff, but they are typically 1/2" wide at least (up to 4" or more).
Of course, I suppose you could buy a large enough round rod that you could carefully machine off the 4 sides to make your own rectangular rod.  As you can imagine, it's a little fragile, but it is supposed to be machinable.  If one could figure out how to gingerly hold it in place under a mill, it might be possible to buzz off the 4 sides.

[Ed Kapuscinski]

Whoa! Great find!

[woodone]

If you need some square material, take a look at Master Carr.
You might find some at a place the rebuilds auto starters .

[peteski]

If you need some square material, take a look at Master Carr.
You might find some at a place the rebuilds auto starters .

Thanks Jerry.

I don't have any immediate need. It was more of a curiosity at this point.  Some early German made N scale models have motors that use square shaped brushes.