Thread: How to polish brass to mirror finish?

For finishing I always use a loose leaf mop, which is just circles of cloth held together at the centre. A stitched mop is for cutting not finishing.
If I am after a real great finish I will use Autosol or similar by hand to finally finish it off after this.

Dave

G'day Will,
What about a scotchbrite wheel?
The speciality welder/fitter used them to polish 316 stainless at my last job.
Cheers, crowie

Cheers Dave
I'm very new to this, so forgive me if this is a naive question: do you use the loose leaf mop with compound of any sort, or just dry - post rouge?
Crowie - can you direct me to which type of Scotch-brite wheel you mean? I see a bunch on the website...
Cheers
Will

The scotchbrite wheels are too aggressive for this sort of polishing.

I think you need to go back to the wet and dry with kero and take it 2000.
Those scratches survived the sanding and are visible because of the polishing not a result of it. To really bring up the shine with brass use the chrome soap. It's best to have a mop for each soap if you can afford it.

Garry

G'day Will,
Something like this one from Blackwoods


WHEEL S/BRITE MTL FINISH 8X2X3 6A MEDIUM (00708603) | Blackwoods

Plus there's some discussion on this thread

https://www.woodworkforums.com/f65/sc...wheels-132648/

Cheers, crowie

Hi Will,

+1 for Autosol.

What colour compound are you using on the buff? Also, if you change colours, change buffs so you don't get cross contamination.

Regards
Ray

EDIT.. I just read you are using white, you might get better results with brown... http://www.caswellplating.com/buffs/buffing.htm

Hey Garry,
I'm pretty sure I sanded (and polished) all the way through the scratches because of the alternating directions. I made sure not to move onto the next grit until there were no visible scratches in the direction of the previous grit. But I'll definitely go buy some 2000 grit and give that a go nonetheless.
Ray, I'm using some white compound (i read that to be good for brass?). It's quite an old block and it's looking a bit yuck and flaky - could it have gone bad?
While we're on the topic of compounds - I believe I read somewhere that Jeweller's Red rouge slightly stains gold in a pleasing fashion. Is this also true on brass? I ask because this brass is just looking maybe a little greenish for my tastes...

Thanks for the link Ray - do you think it would be worth doing black/emery first with one wheel, then brown (then maybe an even finer one?). Or would the black compound be a step backwards from the superfine sandpaper?

Hi Will,

Don't know, I'd just go straight to brown compound and forget the black, as far as your white compound goes, it shouldn't be scratching like that anyway, maybe it has picked up some contamination somewhere along the line..

Also, I'm not sure you need to go all the way to 1000 grit paper before going to the wheel..

Trial and error, polishing is one of the black arts...

Regards
Ray

i use a denim wheel with a fine abrasive paste in the past on copper, then finish it off with brasso, gets hot as hell but comes up mirror finnish.

Hello Will

My training in polishing came about in preparing guns for bluing. There were 2 ways we generally did it. Quality jobs were always hand sanded in W&D from 120 upto 2000. Took a lot of time to do but when blued you'd end up with a blue so deep and rich it'd make a jellyfish hard. Things like extractors and bolts if not jewelled would be given a light tickle on a loose fold mop with tripoli, then finished with white on another mop. They'd shine like a mirror.

2nd method used for the budget jobs was to use a stitched mop with tripoli or auscut(if it was real ordinary we'd start with a sisal wheel ), followed by tripoli on a loose mop, then white on another loose mop. A lot quicker to do and produced good results but it can change the dimensions of the workpiece if you're not careful. On curves or it where it changes shape abruptly you need to be careful or you can wear away more than you realise.


Either way it's boring, dull, and dirty work. Make sure you wear breathing protection.
I would suggest you practice with something other than your guitar thing.(Sorry but I know nothing about luthier work)

Garry

Taking the surface to 1200 is only the preperation to then start polishing, once you have it finished to 1200, then go to a grey (auscut) course compound on a stiched mop, then go to a red compound (Tripoli) on another stitched mop, the to a green ( for non ferrous metal) (white is normaly for ferrous metal) compound on a loose leaf calico mop then to a cream such as reflection on a loose leaf calico mop, with light pressure. For every stage use a mop dedicated to that compound.

I would have thought metal polish should get it to where you want...

Just some thoughts
are these scratches appearing after you used the rouge?..or were they there before you used the rouge?

If after...are you sure your wheel is clean from contaminants?

if before, maybe you still need to keep using the rouge to remove the scratches made by the wet dry?

Is the brass suitable for what your intending...eg could it be cheap chinese crap that is contaminated with other impurities causing the scratches...

Is the rouge clean
and or is it a satisfactory grade (fine or course etc) for that type of polishing..does it come in different grades..

for info only ....A client of mine (who manufacture circuit boards) use differing grades of polishing compounds ..ie I recall seeing grades such as 5, 10 and 15 micron (and plenty of others) marked on the side of the containers.

wsal.

I use to hand carve old pieces of scrap brass, in one of my past lives. That is when scrap yards actually let you go dumpster diving for bits and pieces.

After shaping, usually a fish for a key ring, I would rub down to about 1000 grit wet and dry.

Then, Out came the Dremel. Use one of the white polishing attachments and some Brasso.
Flat out speed is best.

Be warned. The Dremel and brasso, will take metal off your work. So be sure you have enough to spare.

The finish is superb. I would say "perfect" but that cannot be attained, I think.

Paul.

P. S. I also use the Dremel and Brasso to polish stainless steel boat fittings I make.