# Comm Cleaning, T-Jets



## Sir Slotsalot (Jan 23, 2010)

If I've posted about this before, please forgive my redundancy. This fingernail buffing block is the greatest thing I've ever found for gentle and effective cleaning/conditioning of T-Jet comm plates. It provides a smooth, hi-luster finish without harsh abrasion. Works great on track power rails and p/u shoes as well. Only $2 bucks at any Walmart:

http://grocery.walmart.com/usd-esto...r.jsp?skuId=1012806&referrer=cookiesDetecting

Cool stuff.


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## slotking (May 27, 2008)

I would suggest a VRP or JW comm tool!
does the same but also trues the comm
a flat true com reduces brush bounce.


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## Sir Slotsalot (Jan 23, 2010)

Been eyeballing VRP. Good products. Those tools are on my wish list. Need to sell some things to free up some cash.


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## Bill Hall (Jan 6, 2007)

*45 years and counting*

After the comm is cut, I still use a big pink eraser for routine comm service.


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## Sir Slotsalot (Jan 23, 2010)

Bill,

Nice to see you lurking about. Pink eraser is good. Fingernail buffing block gives her a real nice shiny finish too w/ little to no residue. It's all good.


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## clydeomite (May 5, 2004)

Howdy:
I use a q=tip and brasso and then hit it with a Buffing wheel in my Dremel . Talk about shine.
Clyde-0-Mite


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## hojoe (Dec 1, 2004)

I just put a wire wheel on my dremel and have at it. Shines 'em up real good.
hojoe


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## slotking (May 27, 2008)

remember, there are 2 thing here:

truing the comm and cleaning the comm

Truing the com makes the arm run better because you reduce brush bounce
that were the VRP & JW comm truer comes in.

If you run the car a lotm then you can clean the com, with a bunch of different methods, erasers, wire wheel etc..

but remember, over time the brushes will groove the arm plate. So you will want to true the comm at that time.


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## Dyno Dom (May 26, 2007)

Slotking, I have a JW comm tool but haven't yet tried it.
What is your suggestion to best utilize the tool?


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## slotking (May 27, 2008)

the VRP tool comes with a dremel part and a hand part 
http://www.vrpslotracing.com/VRPCommTool.html

The JW tool is simpler and can take some time to true the bad comms
http://jwhospeedparts.com/partspg.htm

I am lazy so I use the dremel tool always to start with.


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## tjd241 (Jan 25, 2004)

I have a few potions for cleaning the heavy stuff you find on an old likely never maintained chassis. Before I reassemble I always polish some of the electricals with Flitz. Seems to work pretty good... As far as the comm goes, you could signal a plane with it.


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## slotking (May 27, 2008)

> As far as the comm goes, you could signal a plane with it


polished shiny is not always flat! 
and boy do I know!


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## JVerb (Oct 6, 2006)

What about not polishing the comm. Just true it and leave the (small) scratches on the comm. A new set of brushes set 
so they don't spin and then a short breakin period. The brushes will now have ridges that match the groves that were left in the comm.
This should increase the contact area between the comm and the brush. It works for me. 

Peace, Verb


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## Bill Hall (Jan 6, 2007)

Although the comm tool corrects both simultaneously; brush bounce and comm grooving are seperate considerations. 

It has been my observation that regardless of how shiny the comm is, the brushes will immediatly start scratching in at their manufactured hardness. As a rule, my first pass with the comm tool is 1200 for a tattle tale. If the brush wear pattern is blotchy or mottled you should be able to finish in 1200 without too much effort. If the wear pattern becomes more pronounced I drop to 800/600 and then finish at 1200.

I prefer not to use the dremel and just proceed carefully by hand. The correct technique is like hand lapping valves in a cylinder head. A short forward and reverse pattern and lift every 130 degrees or so until you complete a full 360 degree rotation or two. This insures a nice flat pattern without cutting concentric circles. Comm service intervals will vary greatly as not all brushes are created equal. Your initial seating time will vary as will your overall service life depending on what brush you choose, and how the brush spring tension is set. Typically the harder the brush the harder the comm is to clean up. This is why you see prettier comms with the vintage attic stuff that was run on brushes with more carbon in them and then they were put away before the advent modern high performance brushes and their entwined relationship with hot winds and aggrevated spring pressures. The higher the brush's metal content the better they transfer current and more severe the segment wear. There will always a trade off between performance and service life.


Comms that require repeat truing for bounce are suspect, generally caused by delamination or warping due to heat. Segment chatter. Also suspect are comms with unusual wear patterns; usually a mechanical thing caused the comm not being parallel to the lams, loose comm plate clamps, or just plain old mounted off center.

No amount of truing and buffing will correct birth defects or poor wokmanship, so it behooves you to examine every armature carefully and treat each one as no more than a core until it proves itself worthy. Remember that all supect cores should be sent to "Sgrigs" so they can live again!


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## Sir Slotsalot (Jan 23, 2010)

AeroCar Conducta Motor Comm Drops will help reduce brush and comm wear. It also boosts conductivity.


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## ajd350 (Sep 18, 2005)

Bill and Verb I see both of your points. I race with Verb and I can tell you he builds some quick cars. Verb, I don't know what grit you finish with. I have had very good results finishing with 600 and breaking in on that. It does not take very long and I have a good wear pattern. Not as pretty as polishing, but it works well. I would add to be careful to avoid pressing on the comm tabs during sanding so the comm is not distorted. Al


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## Bill Hall (Jan 6, 2007)

I'm thinking we agree...:thumbsup:

One day when I was actually paying attention, I realized that breaking in the brushes on a perfectly polished comm was the scale equivalent of doing a lawn job on a putting green. :tongue:


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## JVerb (Oct 6, 2006)

Bill, I use the method you describe for truing the comm except I turn about 120 degrees. When I build a car for someone 
I tell them not to take it apart until I can be there. This way I can show them how to read what is going on. Yes I use 
some lube on the comm and the brushes. Hi, Al.

Peace, Verb


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## Bill Hall (Jan 6, 2007)

*My bad....good catch!*



JVerb said:


> Bill, I use the method you describe for truing the comm except I turn about 120 degrees. When I build a car for someone
> I tell them not to take it apart until I can be there. This way I can show them how to read what is going on. Yes I use
> some lube on the comm and the brushes. Hi, Al.
> 
> Peace, Verb


Yeah DUH! Thats a typo on my part Verb....I light fingered that.... it is now corrected from 30 and reads 130.


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## JVerb (Oct 6, 2006)

Hey, thanks for posting. I was on my way downstairs to try and figure out any advantages to only turning 30 degrees at a time. Thanks again.

Peace, Verb


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## ajd350 (Sep 18, 2005)

Great analogy, Bill....LOL. Man, I was all set to try that 30 degree thing. Never know what may work....... :tongue: 
Looking forward to running with you again, Verb 

Al


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## slotking (May 27, 2008)

it not really all that hard, as i said i do all my testing with a dyno, just few minutes is need to get to top speeds with new brushes.

I do this with very polished comms and slottech brushes which sem to offer the most speed as i write this.

I also PEN the the com slot on inlines and pancake motors, this reduces any sharp edges on the comm.

I have done a lot of dyno testing over the years, and without fail my cars are ready after 5 minutes or less!


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## bearsox (Apr 22, 2006)

*I use a the 600x1200 grit method but kinda twist up what i use for tools is all. I set the whole plate minus idler into my special rubber cork with my sand paper wrapped over it so the arm shaft fits through the hole i punched and into the hole i drilled into the rubber cork. The cork hole was lightly oiled prior to so what i do next won't be at issue . I then load my dremel with the same old gray rubber eraser i once used to clean shoes with . Now i use that placed atop the arm gear to spin and force rotation of the arm below. It now spins up the arm and voila ! I adjust the grit depending on what i need on the given arm . Goofy but hey i wandered around American Science and surplus and found the rubber stopper / cork section one day and said HUMMM !

Bear :wave: *


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## ajd350 (Sep 18, 2005)

More than one way to get the job done. Just don't forget to lube your cork hole!:thumbsup:


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## JVerb (Oct 6, 2006)

Slotking, I have to ask your method in polishing the comm plate. I had to think about how I was going to put that in words and I don't even want to know about the cork hole method. 

peace, verb


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## slotking (May 27, 2008)

ok
1> the cork hole was not me! :freak: LOL

2> whith an older arm, i used the VRP dremel tool to get rid of the crap and flatten the comm plate.

3> using the vrp hand tool i then rough polish the comm to mostly shiny

3>I then use a dremel polishing cloth with the polishing compound to remove 1200 grit lines. that gives a mirror finish which reduces friction.


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## JVerb (Oct 6, 2006)

Slotking, do you use the outside circumference of the polishing wheel and hold the dremel at approximately 90 degrees or do you hold the dremel inline and use the face of the polishing wheel pressed against the face of the comm. Thanks again.

Peace, Verb


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## bearsox (Apr 22, 2006)

bearsox said:


> *I use a the 600x1200 grit method but kinda twist up what i use for tools is all. I set the whole plate minus idler into my special rubber cork with my sand paper wrapped over it so the arm shaft fits through the hole i punched and into the hole i drilled into the rubber cork. The cork hole was lightly oiled prior to so what i do next won't be at issue . I then load my dremel with the same old gray rubber eraser i once used to clean shoes with . Now i use that placed atop the arm gear to spin and force rotation of the arm below. It now spins up the arm and voila ! I adjust the grit depending on what i need on the given arm . Goofy but hey i wandered around American Science and surplus and found the rubber stopper / cork section one day and said HUMMM !
> 
> Bear :wave: *


*Grabbing a junk arm and plate out of a bin... i decided to take a few pics to show what the Goofy method i use KINDA looks like on the fly . Sorry for the bad setup and pics but hope ya can see the black rubber stopper fits the comm perfectly. Obviously the sandpaper is pulled tighter and i go to my outside bench now to use the vise to level things but ya get the jist.

Bear *:wave:


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## alpink (Aug 22, 2010)

nutshell


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## slotking (May 27, 2008)

kind of works the same way as the JW tool. Not sure if any spins their arm with a dremel on the gear like that?? I would have 2 concerns with that method.
1>trueness of the surface that faces the comm
2> using the dremel on the gear for some rules may DQ the car if the gear gets to thin and it may cause spots on the gear that could unbalance a nice gear.

the VRP set make it real easy:


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## bearsox (Apr 22, 2006)

slotking said:


> Not sure if any spins their arm with a dremel on the gear like that? I would have 2 concerns with that method.
> 1>trueness of the surface that faces the comm
> 2> using the dremel on the gear for some rules may DQ the car if the gear gets to thin and it may cause spots on the gear that could unbalance a nice gear.


Hi Mike ,
1.) the part that i use to spin the gear is actually an eraser that was cut and ground round to fit the dremel so no wear to gears . It just spins em up to an adjustable speed via dremel.

2.)trueness of surface ummm maybe ??? but truthfully very hard to tell . Hard rubber surface getting a flat sheet of sandpaper atop ??? ERRR UMMM IYA DUNNO i never really had an issue . Same story using a pumice stone cut on a 45 degree angle then used a eraser to clean final touch but hey i try odd stuff ! 

Bear :wave:


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