Making copper shiny!

Unless somebody has a chemical or electrochemical treatment to offer, I'd go with jeweler's rouge and a couple of buffs on a (cheap) die grinder.

*That's* shiny. And the work goes fast and easy.

-- Ed Huntress

Not much good, as it is too hard to get around all the protuberances. Also, I work from home, so some quieter method is also good.

By the way, there are no fine details that need to be preserved.

I knew of a coin collector than owned a bar. He used to keep his urinals full of pennies to shine them up. If you buy the beer...I could supply a bunch of volunteers to help you shine them up.

Your best bet is probably a vibratory tumbler, same kind used to clean and polish cases for reloading. You can get a decent smaller unit for around $100 from a gun store or some decent sporting goods stores. There are a number of different types of polishing media you'll have to try to find the one that works best. If you get the unit at a good gun store with people who know how to use them bring a sample part and they can probably recommend the best media to try.

Pete C.

Again, no good because a) they are probably too big, and would not tuble real well! If you want to see what I am polishing, go to

They do indeed look to big for the tumblers you would find at a gun store, I missed the 500mm part.

I think you might need to build a clothes dryer style tumbler drum. I'm thinking something like a 30gal poly clamp band type removable head drum. Make a base for it with two powered axle shafts with rubber wheels for the drum to sit horizontally on and a horizontal idler wheel at each end so the drum can't walk off. Probably want the thing to tumble pretty slow, perhaps 5-10 rpm max.

Put enough polishing media in the drum to fill about 6" deep at the bottom when the drum is on it's side. Stand the drum up and remove the head to load perhaps 10 parts depending on how bad the protuberances are, cover and then place on the tumbler base to tumble for a day. Not particularly fast, but low labor and should be cheap enough to build a second one if you need the production speed. Could build one base with a single motor that would tumble two or even three drums.

Test the theory with a 5gal plastic pail and one or two parts placed in a regular cloths dryer with towels packed around to stabilize (heat off of course).

Pete C.

Look into copper electroplating using a "leveling agent" or "shine enhancer" (really an organic additive used to make the plating shiny.) You could dip the parts and in about 1 minute have a very shiny, real copper coating. Try here or google for more info:

Coca-Cola. No shit, give it a try. Works for filthy shop clothes/rags, too.

Wont this put a copper coating on the brass too?

This is an easy one. Start with polished copper that has been laquered. If you suspect the object will be exposed to the elements give it a coating that blocks UV

Try soaking them in buttermilk.

That would require having polished copper to start with, plus I am silver soldering to it

A number of acids will do this: dilute HCL, phosphoric acid (CocaCola contains phosphoric acid), etc. BAM, a product by Easy-Off for removing hard water stains, is shown brightening an old penny in a TV ad. Oxalic acid might work.

Unfortunately, most acids attack zinc vigorously. This means that any brass will have it's zinc attacked near the surface and turn pink or copper-colored.

"Bright" and "shiney" are different. Bright means free of oxides; shiney means that plus with a polished highly-reflective surface.

I would experiment with sodablasting. That's used to clean fine mechanisms as for aerospace, and it's also use in dentistry for removing stubborn plaque.

It's like sandblasting but uses ordinary baking soda, or washing soda (sodium carbonate) which is also used for raising pH in swimming pools. Take one of your gizmos to a place that does sodablast and see how it works, or just try some soda in one of those small $39 hopper-fed blasters. Do this outoors, because I expect it would make quite a mess. If soda seems to work well, I'd think you could build a sodablast box fairly easily out of readily-available materials. Another poster made a gritblast cabinet out of a plastic storage tub from Wal-Mart. You'd probably need a vent stack; I'd make that vertical, out of 3" or 4" material so the air velocity in the stack is low and most of the air-entrained soda eventually falls back into the box. It might help to put a centrufugal cyclone separator (3 pound coffee can, tangentially fed and axially exhausted) in the vent line. The trap would need to be emptied periodically.

I have not done this for finish, but I have brush air blasted some copper, it really did get that shiny new copper look. You might look into blasting with walnut shells, baking soda, or some other gentle medium.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

What does a blaster look like? Can someone send me a link to a pic so I can have a look for one in Australia?

One version of the small blaster that might serve to experiment with soda is item # 92857 at

Lots of stuff, including cabinets and plan and/or kits to make your own cabinet at:

I particularly recommend their S-25 gun. It is far superior to any other siphon gun I've ever used. I've never tried it with soda, but it works great with the usual grits -- sand, aluminum oxide, glass beads, and crushed walnut shells.

Crushed walnut shells may well work well for you. I've used that to clean rather tenacious paint from brass items without marring the underlying brass. It didn't polish the brass, but it didn't degrade the surface finish either. The result was bright brass that had the "as machined" surface finish which was pretty good though not buffed to a mirror finish.

The application was some old precision bubble levels from tank periscopes or something that had decades-old tough green drab paint on them. They cleaned up very nicely.

I noted that blasting soda with "large, jagged irregular shape" is available from

I wonder if blasting soda might therefore be coarser (larger particle size) than household baking soda, though chemically identical. That might make it feed better in a blaster.

An advantage to soda is that, unlike other blasting media, it's water soluble. A wash with warm water would remove all of it from nooks and crannies in the workpiece, leaving no residual grit.

You might consider sending your stuff out to be cleaned up and polished. There are companies that do that. They have the techniques and capital equipment for the job. I know that because I had a very good friend and fishin' buddy who started and ran such a business. It was called "Deburring, Inc". We became good friends during the course of my pursuit of his daughter, who is now my wife and companion of more than 20 years. He was also a machinist, fisherman, pretty decent stick weldor and a vet.

They deburred, cleaned, and polished everything from cellphone antennas and snowmobile skids to heart valves and stainless steel hip joint replacements. A lot of their stuff was done in batches, in big rotary machines he called "Harperizers" that were charged with a load of workpieces, suitable abrasive media, sometimes some liquid, and then run for a while. Bernie didn't tell his process secrets, but I have a hunch that the media he'd have used on your parts might have been crushed corncobs. You may know of what we call corn as maize. That might well do some polishing as well as cleaning.

I've no idea what the per-piece cost might be for your stuff at a comparable place near you, if there is one, but I'll note that the basis of his biz was that he could do such things for less than the companies who needed it done could do it themselves if they even could do it themselves. The company is still in bidness though Bern has been gone for over a decade now.

I wonder if there's any blasting media which might be used for polishing? Baking soda? At least, can it get you closer to polished and do the "heavy lifting" for you?

That was my initial thought, but he's talking things 18" tall by 4" across.

OK, so let's combine that idea with my just posted blasting idea - what about blasting it with the same media used in a vibratory polisher - corncob with polishing agent? Might be faster than you'd think. If my blast cabinet hadn't _just_ been switched over to another media, I'd offer to give it a try. (for the record, it's a pain in the ass to switch from one media to another - if anyone has a better idea, let me know)