Brass polishing question

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Hi all, I've started my brass church panel project and am not sure if I'm polishing the brass correctly. I'm using Brown(Tripoli) buffing compound on a spiral sewn wheel on my bench grinder. I then move to a looser buffing wheel with the white compound. For both process I briefly touch the stick to the wheel and then polish out about 6-9 inched of bar stock then touch the stick to the wheel again and move on. For the most part the pieces have turned out pretty good, but I've been getting this streaking of the compound or something on the brass. On the Tripoli wheel the streaks take on a copper like tint. When I'm finished polishing I wipe these streaks off with a soft t-shirt rag, but at times it takes some effort and I end up putting marks on the brass. I tried using MEK, which sort of worked, but in places it turned the brass cloudy. Any idea what is going on? How to stop it? Or how to remove it without scratching the brass? I've posted picts of what the streaks look like and the tripoli wheel.

brass polishing 1


brass polishing 2

brass polishing 3

 


warren's picture

Interesting

Are you dressing your buff everynow and then to remove the metal film? Looks like it could use a dressing with a buffing rake. I use a bunch of nails hammered in a circle in a piece of wood.

Why the white compound isn't that for steel? I would think Tripoli and then rouge. Messy job any way you put it.

warren
http://www.metalrecipes.com


eligius1427's picture

Hi Warren, I've been using a

Hi Warren, I've been using a file card which doesn't have very aggressive teeth. I'll try finding a rake or use your nail idea. Will brings up a good question, how aggressively should I dress the wheel? As for the white compound, I was just following the suggestions on the back of the packaging of the wheels. I'm very new to polishing, which I guess makes me a little gullible/naive as well. It seemed to work pretty well however.

Jake


Will Jones's picture

brass polishing

Glad you asked this one. I always get the same problem. Like you say those streaks are hard work to move by hand, and you kind of feel like you might as well have polished by hand to start with! Hope we gety some illuminating answers.
I do give my wheel a rake, but I'm never sure how aggressive to be with it. I usually just use the brown polish; the white in my kit is pretty tough stuff for stainless and the like.
Will Jones, www.ironwill.org.uk


eligius1427's picture

Hi Will, I'm sure some of

Hi Will, I'm sure some of these seasoned metal working veterans will have a good explanation for us. I really like you work by the way. Look forward to seeing more.

Jake


Nathan Logsdon's picture

Hey Jake- glad the

Hey Jake- glad the commission is kickin off. Looks like two things are happenin. Like Warren said you need to rake your buff, but it also looks like you may be using too much pressure. Your are essentially melting the compound off the wheel and back onto your piece. Back off your pressure or try starting with a black emery compound. i used to work for a knife manufacturer and we always hit brass on a scotchbrite wheel before going to buff. Then we went to green compound on sewn buff and then finally to white compound on a loose buff. Not a perfect mirror shine , but really nice and fairly quick. Clean off residue with denatured alcohol or laquer thinner. Watch the pressure or you will scorch the piece. Good luck.


eligius1427's picture

Thanks Nathan, I'll try the

Thanks Nathan, I'll try the black emery compound today. I suppose if I'm try to do too much with the less abrasive tripoli compound, it could easily lead me to pressing harder. I'm not sure what the green compound is, but I'll look for it.

Were you ever able to snap a few picts of your new treadle hammer? I would love to see it and hear how it works.

Jake


Dick C's picture

Like Warren mentioned, you

Like Warren mentioned, you ought to rake your wheel a bit more often. When it gets loaded with brass then that's what your polishing with.  I like raking wheels with a carborundum stick to avoid adding steel to the wheel, but that might be mostly a psycological thing. Nails would work fine.  As you work, the mixture of abrasive, binder, and removed metal becomes drier, and once it adheres it sticks pretty well.  I use a small amount of lamp oil to keep the polish lubricated.  I imagine kerosene or fuel oil would work as well.  If you use red rouge, that is often water soluable, so soapy water will help with a caking problem there.  


eligius1427's picture

Thanks Dick, do you add the

Thanks Dick, do you add the lubricant directly to the wheel? If so, does it throw liquid all over when you apply it? Just want to be prepared. First time I tried applying liquid polish to my spinning buffer led to an exciting couple of minutes. Kind of had a Jackson Pollock theme in the shop for a while. :)

Jake


Dick C's picture

I'll brush or wipe a little

I'll brush or wipe a little on the piece when I think it'll help. If you have polish adhered to your work a small amount wiped on will dissolve and loosen it. I don't like using it though. I don't care to breath it. At times It does help and fortunately you don't need much.


Dick C's picture

I'll brush or wipe a little

I'll brush or wipe a little on the piece when I think it'll help. If you have polish adhered to your work a small amount wiped on will dissolve and loosen it. I don't like using it though. I don't care to breath it. At times It does help and fortunately you don't need much.


marilyn's picture

Yes, this is not unusual.

Yes, this is not unusual. You may be putting on to much compound. I wait until I see the color of the metal being buffed on the buffing wheel. I wipe the compound bar lightly across the buff. I don't rake the buffs. I don't like to get dangly threads because they can scratch the metal surface. Dawn detergent does a good job of dissolving compound from nonferrous metal

marilyn


visitor's picture

compound on brass

After making sure that you are using the proper compounds, the best thing to fix your problem is HEAT! As long as the brass is cold...or even just warm,compounds tend to stick.
Either buff hard enough to get the piece hot,or do as i do.
After initial buffing(sometimes prior to buffing) and before the piece is colored or finish polished with white compound,i heat it in my oven to between 150-200 degrees. This should make life a lot easier. Better to start with a hot pc., as opposed to busting your ass buffing it till it gets hot enough.
It used to drive my dad crazy because"they never did it like that"
It works...and i'd never go back to cold polishing.

Scott Ciardi. President E.Ciardi Co. eciardi.com