I make a lot of copper pieces, and need them to be really shiny.
They are about 500mm high and 50mm round, with a few bits and pieces
protroding which makes polishing really difficult.
I make HUNDREDS of them, so elbow grease is really not an option.
I am sure there is some kind of dip or something that can make them
I have tried a cream clenser which actually cleans them quite well, but
leaves them quite dull.
I need something that can clean them, AND leave them bright and shiny.
Also, there are some brass parts (which go pink if you soak it in
What can I use? I dont mind making a decent setup if need be.
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.
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.
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
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,
| Hi guys,
| I make a lot of copper pieces, and need them to be really shiny.
| They are about 500mm high and 50mm round, with a few bits and pieces
| protroding which makes polishing really difficult.
| I make HUNDREDS of them, so elbow grease is really not an option.
| I am sure there is some kind of dip or something that can make them
| I have tried a cream clenser which actually cleans them quite well, but
| leaves them quite dull.
| I need something that can clean them, AND leave them bright and shiny.
| Also, there are some brass parts (which go pink if you soak it in
| What can I use? I dont mind making a decent setup if need be.
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
"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
(top posted for your convenience)
Keep the whole world singing . . . .
DanG (remove the sevens)
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
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.
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