Need some assistance in taking out scratches in brass....

[Leszek Vogt]

Howdy all. Normally I'm pretty handy, but this hardware on this 5x7 stumped me. I was able to revive the brass pieces to look really nice, but there are still some tiny scratches. Is there a way to buff this out, or should I just throw up my hands, reassemble everything, go somewhere and photograph vs obsessing over minutia ? :confused: Are there any pro products that would involve a paste + drill/Dremel....or ? Thanks in advance.

Les

[mdarnton]

To remove scratches, you always have to go back to the grit that would cause such a scratch. If you try shortcuts, you end up only with polished scratches. Or. . . you can sand much longer at a higher grit. As a compromise, I would start with 600 wet-or-dry sandpaper, with a hard backing like an eraser and some light oil--baby oil would be good, and go over the whole piece, as a flattening operation. Then try 0000 steel wool, and finally some polish. In general, you should always go in straight lines, in the same direction, not criss-cross--that way any fine scratches you leave will be organized and neat, and use a stiff backing when possible so that you don't round over edges, which is the sure sign of an amateur.

If you want it to look nicest, at each stage do the whole piece, not just a small area, so that the whoe thing goes together.

[EdSawyer]

What he said.

A dremel doesn't really have enough torque to act as a buff. You really need a large 3/4hp motor for a buffer to do it right. a jewelers buff might work but a big one would definitely work great. You would still need to go through various grits but could do all the hardware in an hour or less probably, using a machine buffer.

[Jac@stafford.net]

An alternative is to go for a different look and have the part shot-peened for a luster rather than a fragile shine. Choose the technician carefully.

[BradS]

howdy all...... Should i just throw up my hands, reassemble everything, go somewhere and photograph vs obsessing over minutia ? :confused:

Les

yes!

[IanG]

Wire wool then brass polish works extremely well, if needed use wet & dry paper first. I use both for aluminium and brass parts and you can get a perfect finish.

Ian

[Jim C.]

How shiney do you want that brass to be ?
If it's an old camera then leave the little scratches in as a badge of age, if you want a mirror like polish and take the scratches
out then contrary to what EdSawyer said I use a Dremel with their Scotchbrite wheels ( # 511E ) , they shed like anything so get
more than you think you need, I don't know why they don't offer bulk packs.
One is beige ( coarse ) and the other is gray (fine ), the gray wheel does a great job at getting out fine scratches,
hand polish with a metal polish, I use Presta Metal polish which I got at Pep Boys or Auto zone ( i forget ).

[Leszek Vogt]

Thanks for the suggestions. Before I go to "0000" wool, I thought I'd try some sand paper (on the reverse side of the hardware). One fella on my hill gave me some 12,000 sandpaper....I was quite surprised that such even existed. Yes, it does shines up, but amazingly it still leaves minute scratches.

Les

[indy_kid]

You're always going to have scratches; it's a fact of polishing something. However, you can minimize them by using progressively finer grits, whether it be sandpaper, emery cloth, or a liquid/paste polish.

I can remember prepping metal samples for a Materials Science course in college, and we had access to whetstones of increasingly finer grit. After running through the 5 wheels (like polishing a diamond, and yes, diamonds have scratches!), the sample was like a mirror to the naked eye, but scratches were HUGE under magnification. Took time and effort to master the technique. Unfortunately, after all that polishing, we had to etch the metal with acid to bring out the crystal structure that would then be photographed under high magnification. Goodbye mirror finish!

Keep in mind that you're removing metal in the process. If it's an old lens or other part, repeated polishing might compromise strength. Differential expansion between thich and thin walls might warp the light as it passes through the lens (though I suspect the lens would be fairly gone at that point). I'm simply recommending caution vs. your desired cosmetic effect.

I'd recommend aluminum polish and plastic polish for your final attempts. I've used plastic polish to remove fairly deep scratches from acrylic sheets, leaving behind only the finest scratches. I've even used it on my glasses, without harming the prescription.

I'd also recommend that you get a small piece of brass to practice on before attacking the piece in question. Fine-tune your skills - finger pressure, thickness of the paste, etc, before working on the actual piece. You can compare/contrast all of the suggestions to see what might work best for you. Keep in mind that brass is an alloy, so the results might be a bit different between the test brass and the actual brass due to variations in tin/copper content.

Post some before and after pics to help others in the future!!

[E. von Hoegh]

Howdy all. Normally I'm pretty handy, but this hardware on this 5x7 stumped me. I was able to revive the brass pieces to look really nice, but there are still some tiny scratches. Is there a way to buff this out, or should I just throw up my hands, reassemble everything, go somewhere and photograph vs obsessing over minutia ? :confused: Are there any pro products that would involve a paste + drill/Dremel....or ? Thanks in advance.

Les
If there are large/deep scratches, sand them out with 600 grit paper used wet, then finish it with OOOO steel wool. Here's something to keep in mind: as long as all the marks are uniform and run in the same direction, it will look great - look at an old lens with a lacquer finish - not polished, but 'grained', and they look fine.
The shinier you make it, the more apparent future marks will be.
If you want dished out holes, rounded edges, and smeared engraving use a power buffer. Power tools take time, experience, and lots of ruined parts to master.

[Jac@stafford.net]

finish it with OOOO steel wool

Thank you for bringing that up. I know nothing about polishing or restoring brass, and was chastised once when I used 4/0 steel wool. The guy said it would contaminate the brass. I don't know how the item turned out lover time because I sold it.

What do you think about using bronze wool?

[E. von Hoegh]

Thank you for bringing that up. I know nothing about polishing or restoring brass, and was chastised once when I used 4/0 steel wool. The guy said it would contaminate the brass. I don't know how the item turned out lover time because I sold it.

What do you think about using bronze wool?

Bronze wool is mainly for wood (so you don't get rust spots from bits of steel trapped in the grain) and very soft surfaces, it's expensive and doesn't have the 'tooth' of steelwool.
How on earth could steelwool contaminate brass? The only thing to keep in mind is that as purchased, steelwool has a rust inhibiting substance on it, soak it in lacquer thinner to remove this or finishes might not stick.
I used 4-0 steelwool to refinish a lens barrel prior to relacquering it, sometime around 1990 - 1992, it's holding up just dandy.

[E. von Hoegh]

An alternative is to go for a different look and have the part shot-peened for a luster rather than a fragile shine. Choose the technician carefully.

Polishing, then acid etching followed by lacquering gives a nice finish too. Practice on scrap metal!

[rdenney]

What he said.

A dremel doesn't really have enough torque to act as a buff. You really need a large 3/4hp motor for a buffer to do it right. a jewelers buff might work but a big one would definitely work great. You would still need to go through various grits but could do all the hardware in an hour or less probably, using a machine buffer.

That depends on the size of the piece. I've buffed with a Dremel many times on small pieces with good success. I've also buffed tubas using a 3-HP, 16" buff, so I'm not unfamiliar with big stuff. But if you try to buff a small piece on a big buff, there's a good chance you'll be digging it out of the drywall across the room, using broken fingers.

I prefer the 1/2"-diameter hard buffs on Dremels for small brass parts. If you want a high polish, sand to remove the scratch, double the grit number, sand again, and repeat until you get to 400. Then, polish using a buff and tripoli (usually in a yellow cake), followed by white polish, followed by rouge (red polish). Never run the buff into an edge--ever. You'll file the edge down. Buff from the flat surface towards the edge, so that the buff is traveling off the edge, not onto the edge. That will help keep the edges crisp.

Recognize that all buffing is removing material, which will change the dimensions of what you are buffing. Were it me, I'd live with the scratch.

Rick "properly respectful of large buffs" Denney

[rdenney]

Thank you for bringing that up. I know nothing about polishing or restoring brass, and was chastised once when I used 4/0 steel wool. The guy said it would contaminate the brass. I don't know how the item turned out lover time because I sold it.

What do you think about using bronze wool?

I agree, but it's even more true for aluminum. You'll end up with iron grit in the metal, and if allowed to rust it will look terrible. Almost impossible to get out.

I've polished many brass items to a mirror finish. Scotchbrite does the same thing as steel wool, but it isn't steel and won't leave metal bits embedded in the brass. But sandpaper works just as good.

Rick "who'd rather have scratches if the material is thin" Denney

[Leszek Vogt]

Thanks all for the input.

Rick, I've tried Scotchbright (relatively fresh pad) on the reverse side of the hardware piece, and I noticed some small scratches. Anyway, I scratched that idea real fast.

E. von Hoegh, what sorts of lacquer were you suggesting to protect cleaned/polished surfaces ?


The '0000' steel wool is real nice and it does not bite....I didn't try it against the grain, since I didn't wanted any wicked effects. The vinegar-salt mixture works really well. It softens the 100yr+ funk and I use Flitz Polish to follow up, and from appearances it takes me back to the original shine of the brass.

Mostly I'm v. pleased with the results, however I do have couple of unexpected difficulties: how to clean the rails, that the gears travel over ?.....without immersion, since it can turn the wood dark due to vinegar content ? Question: does the vinegar have effect on on stained wood ? The other issue is the rear portion of the camera have these side supports that were pressed-in and I'm unable to take that apart and clean them seperately as good as I'd prefer. My only solution is to dip it in v. shallow vinegar mixture, preventing the wood to touch the mixture. It's getting there slowly.

Les