Brush Glaze

Old 06-28-2004, 10:04 AM
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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.
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Old 06-28-2004, 12:23 PM
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The question is why didn't you change the brushes after you cut the comm?
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Old 06-28-2004, 12:29 PM
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Because the brushes weren't worn very much and I need to scrounge every penny possible.
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Old 06-28-2004, 01:07 PM
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you may not see maximum power without new brushes.
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Old 06-28-2004, 01:09 PM
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by the time your current brushes wear in to the new comm face and circumfrence, they may be subjected to excessive heat.
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Old 06-28-2004, 01:22 PM
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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.
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Old 06-28-2004, 02:11 PM
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i guess budget racing is the name of the game.
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Old 06-28-2004, 05:15 PM
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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.
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Old 06-28-2004, 05:31 PM
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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.
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Old 06-28-2004, 05:35 PM
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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?
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Old 06-28-2004, 05:38 PM
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yes
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Old 06-28-2004, 05:58 PM
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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.
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Old 06-28-2004, 06:45 PM
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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.....
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Old 06-28-2004, 08:50 PM
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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!!!
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Old 06-28-2004, 09:13 PM
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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
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