R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 06-28-2004, 11:04 AM   #1
Tech Fanatic
 
Cardboard's Avatar
 
Join Date: Feb 2004
Location: Flushing,NYC
Posts: 843
Send a message via AIM to Cardboard
Arrow Brush Glaze

hi.
About an hour ago, I cut the comm on a monster stock I had laying around. I think it went through about 14 runs without being cut. Didn't change the brushes. I broke it in at 4.8v for 4 minutes. Uopn examination, the brushes are split half/half shiny/glazed. They were split right down the middle with a perfectly straight border. What gives?
The brushes are trinity 4499 dual shunt if that makes a difference.
Cardboard is offline   Reply With Quote
Old 06-28-2004, 01:23 PM   #2
Tech Elite
 
Neil Rabara's Avatar
 
Join Date: Jul 2002
Location: Lone Star
Posts: 4,821
Default

The question is why didn't you change the brushes after you cut the comm?
Neil Rabara is offline   Reply With Quote
Old 06-28-2004, 01:29 PM   #3
Tech Fanatic
 
Cardboard's Avatar
 
Join Date: Feb 2004
Location: Flushing,NYC
Posts: 843
Send a message via AIM to Cardboard
Default

Because the brushes weren't worn very much and I need to scrounge every penny possible.
Cardboard is offline   Reply With Quote
Old 06-28-2004, 02:07 PM   #4
Tech Master
 
Join Date: Jun 2004
Location: SoCal
Posts: 1,099
Trader Rating: 6 (100%+)
Default

you may not see maximum power without new brushes.
trigger is offline   Reply With Quote
Old 06-28-2004, 02:09 PM   #5
Tech Master
 
Join Date: Jun 2004
Location: SoCal
Posts: 1,099
Trader Rating: 6 (100%+)
Default

by the time your current brushes wear in to the new comm face and circumfrence, they may be subjected to excessive heat.
trigger is offline   Reply With Quote
Old 06-28-2004, 02:22 PM   #6
Tech Addict
 
JohnMatrix's Avatar
 
Join Date: Feb 2004
Location: Newark, CA
Posts: 608
Send a message via AIM to JohnMatrix
Default

I would just take a com brush and take off the glaze.

As for getting new brushes I'm 50/50 on that.

I know guys that change there brushes every time they cut.

I dont though, according to BIG JIM, who is suppost to know all on motors, he feels ppl change their brush to offten.
JohnMatrix is offline   Reply With Quote
Old 06-28-2004, 03:11 PM   #7
Tech Master
 
Join Date: Jun 2004
Location: SoCal
Posts: 1,099
Trader Rating: 6 (100%+)
Default

i guess budget racing is the name of the game.
trigger is offline   Reply With Quote
Old 06-28-2004, 06:15 PM   #8
Tech Elite
 
PitCrew's Avatar
 
Join Date: Sep 2003
Location: Seattle Indoor Raceway
Posts: 2,129
Default

To really answer the question withough giving the guy crud over not changing brushes....

Your brush hood are not aligned so that the bushes axis is not perpendicular to the axis of the comm.

Don't feel bad. I re-use brushes all the time. Just clean them with a comm stick, and use them again.

Except at really big races...... Then cut, new brush and 2 volt break in.
PitCrew is offline   Reply With Quote
Old 06-28-2004, 06:31 PM   #9
Tech Elite
 
Neil Rabara's Avatar
 
Join Date: Jul 2002
Location: Lone Star
Posts: 4,821
Default

With a crack in the brushes, don't reuse the brushes. That's what I was referring to. If the color is still there, by all means use them. With cracking like that, get rid of them.
Neil Rabara is offline   Reply With Quote
Old 06-28-2004, 06:35 PM   #10
Tech Addict
 
Join Date: Mar 2002
Posts: 593
Default I run my brushes till they are 50%

FOR ME, it works. My motors are fast, and once the brush fits the com, it takes only a minute to re seat them after cutting the com. I agree, the brushes are made of the same stuff all the way through. If they get shorter, you might have to add a little spring tesion to keep it the same as when the brushes were longer. If they are glazed, clean them with a green com stick or I use a brass wire tooth brush. It roughs up the face, removes all glazing and lets me see when the brush is seated completly after a rebuild. Call it budget racing if you want, but if the brush isn't worn out, why replace it? WILL YOU GO FASTER?
David Root is offline   Reply With Quote
Old 06-28-2004, 06:38 PM   #11
Tech Master
 
Join Date: Jun 2004
Location: SoCal
Posts: 1,099
Trader Rating: 6 (100%+)
Default

yes
trigger is offline   Reply With Quote
Old 06-28-2004, 06:58 PM   #12
Tech Master
 
Join Date: Jun 2004
Location: SoCal
Posts: 1,099
Trader Rating: 6 (100%+)
Default

even if the brush is compose of the same material all the way down. i bet at 50 percent it has been exposed to some excessive heat.
trigger is offline   Reply With Quote
Old 06-28-2004, 07:45 PM   #13
Tech Fanatic
 
Cardboard's Avatar
 
Join Date: Feb 2004
Location: Flushing,NYC
Posts: 843
Send a message via AIM to Cardboard
Default

Oops, sorry I didn't make this clear......
the brushes aren't cracked. I was just asking about the weird issue with color. It's an almost perfect color border right down the middle so I just thought that was kinda peculiar.....
I guess i'll go brush them off and make an attempt aligning the hoods.....
Cardboard is offline   Reply With Quote
Old 06-28-2004, 09:50 PM   #14
Tech Elite
 
TeamButter's Avatar
 
Join Date: Dec 2002
Location: Florida
Posts: 2,802
Trader Rating: 3 (100%+)
Send a message via AIM to TeamButter
Default

As Pitcrew posted below, it sounds more like brush hood alignment issue. You will notice that half or a portion of the brush face appears to be realy shiny copper and the other half sort of looks burnt.

This is as a result of not having full contact between the Comm and the brushes. Try aligning your brush hoods and then see if there is a noticiable increase in performance from your motor.


I am betting there will be!!!
__________________
Xray / BMI Racing / KO Propo / Team Epic / Parma-PSE / High Velocity Racing / TeamButter / P3 Graphics / MDI Racing
TeamButter is offline   Reply With Quote
Old 06-28-2004, 10:13 PM   #15
Tech Master
 
burbs's Avatar
 
Join Date: Feb 2004
Location: wisconsin
Posts: 1,152
Trader Rating: 1 (100%+)
Send a message via AIM to burbs Send a message via Yahoo to burbs
Default

most guy round here reuse brushes for a long time.. but they use a brush contour tool to re shape them, or a serrator...

if the brsh has an discoloration they are most likley junk... that means they got hot and the oils in the brush will dry out. and then u wil see a major loss in pe4formance... and the heat will keep coming back...

i recomend no more then 6-8 runs on a motor before it gets cut.. this not only helps the motor but the brushes

after to many runs the arcing on the cam causes it to discolor. thus requiring more passes on the lathe... meaning u take off more matirial then u should... the smaller the comm gets the slower the motor gets... anything under .270 in size is to small.. they look good on a turbo or a dyno but fail on the track...

aslo by cutting miore frequently will help the brushes run better.. meaning less heat and glaze or discoloration...

also a 3 dollar set of brushes is alot cheaper then a 35 dollar motor
burbs is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Trinity Tru Lathe 3 with Diamond bit/Trinity Brush Station/ Putnam brush driller Brian Anthony R/C Items: For Sale/Trade 10 05-28-2008 08:01 AM
Brush slotter, GT7, Pulsar 2, Comm drops, and Fussy brush serrator and shaper bigdog xxx-s R/C Items: For Sale/Trade 6 09-15-2007 07:44 AM
NOVAK New XBR Sport Brush/Brush Speed Control rcforum Electric On-Road 42 09-03-2007 12:45 PM
To brush or not to brush??? EHHH??? dmlk Rookie Zone 34 11-29-2005 02:20 PM
RC4115 Brush Factory 2 Brush Factory 2 the black one mint shape jason cheng R/C Items: For Sale/Trade 1 12-11-2004 02:27 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 08:52 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net