How to Make Native Copper Shine Again
General Cleaning native Copper.
1st Jun 2005 22:40 UTC John Steenbergen
Hi in that location adept people,just wondering if you tin help with this little problem.I supose it has been asked many times over. I have a lot of Copper laying around both stuff that has gone through the smelter and likewise large natural specimens of native Copper. Have tried many means of cleaning this and making it wait pretty just to no avail The strongest stuff i tried is the hydrocloric acids this cleans it just cute until i take it out so it turns green.I don't actually become any stronger and so this acid is at that place something on the market that will take the tarnish and dull copper await off and arrive polish? Such a pitty to take these beautiful large specimens sitting hither and looking so slow and ugly. Maybe some of you might know of a simple way to clean these? John
2d Jun 2005 00:26 UTC Alfredo
Vinegar and a toothbrush is all I apply to clean the native copper pseudomorphs after aragonite from Republic of bolivia. I guess information technology would work equally well on any native copper. Cleans without leaving an unnaturally bright surface.
2nd Jun 2005 08:14 UTC John Steenbergen
Okay Alfredo i shall have a go on the solid chunks and see how it goes but what about the wiry stuff? Whatever idea there? Some of the ones i have are like a birdnest. Thanks for the tip anyway John.
2nd Jun 2005 14:13 UTC Alfredo
For "birds nests", use vinegar followed past an ultrasonic cleaner rather than scrubbing with a toothbrush. Cheers, Alfredo
second Jun 2005 17:twoscore UTC Chris van Laer
John: Try neutralizing the effects of acids by soaking them in a solution of common blistering soda, then scrub/ultrasonic.
tertiary Jun 2005 eleven:36 UTC Rock Currier
If you have the nerve to try something stronger you can try an acid dichromate solution to clean copper. This has been used commercially past diverse mineral dealers in the past. Take some concentrated sulfuric acid, add together about five% by weight or potassium dichromate or chromic acid and stir till dissolved. This will requite a thick dark red/brownish solution that will immediately eat up what ever it touches, merely it will unremarkably clean copper quite beautifully. This is a very dangerous reagent to use unless yous know what you are doing. Utilize safe gloves an acrid resistant apron, and eye protection. Do not put or pour water into this reagent equally it will exist converted instantly to steam and blow right back out at y'all. Information technology will completely eat up a damp paper towel in just a few seconds. The copper is ordinarily very bright and many people think that it is just too vivid to await any where near natural. The copper only needs to remain a brusque time in the reagent and when you accept it out you should immediately launder it off in large quantities of cold h2o. If yous want to clean copper half breeds from Michigan I can give y'all another reagent to clean this textile well if you want the silverish to be extra vivid. Stone
3rd Jun 2005 14:16 UTC David Von Bargen
One of the problems with doing this is you really should properly dispose of this cleaning solution (the chromium is what got a lot of plating concerns into trouble with the EPA).
3rd Jun 2005 22:57 UTC John Steenbergen
Howdy ,thank you all for the tips but this stuff Stone discribes is a no no equally information technology is just non worth the bother and chances are i would spill some knowing me. I call back i leave them as they are or dump them. I only thought at that place was a safety way,a solution of some sort that would do the trick. Afterward having a talk with my practiced friend from the Brisbane museum,he strongly advised me not to use the stiff accids and reckons it could kill a person if spilled on any role of the body. John
4th Jun 2005 fifteen:28 UTC Mike
You might not be neutralizing your acid enough after cleaning it. If the hydrocloric is working good for cleaning, just try to neutralize the specimem more after you're done cleaning it.
fourth Jun 2005 23:01 UTC John Steenbergen
One thousand'day Mike,you got me going again,you lot say in your letter (you may non be nutralizing ) What do you hateful past this? Every bit it comes out of the hydrocloric acid it is beautiful and shiny,but what happens next is i wash the acid of the specimen with enough of water. And bingo inside a affair of time the beautiful specimen turns dull again and starts to go green.And then i thought well i'll fix this problem and sprayed information technology with hairspray. No good! Somebody said stick information technology in milk which sounded stupid, but ofcourse i tried. Then vinigar,then something else, only all failed.Just information technology is a challence and am having fun. John
5th Jun 2005 04:24 UTC Alan Plante
The rule of thumb is that yous need to rinse the specimen in clean running water for three times as long as you soaked it in acid. So for each 60 minutes of acid bath you're looking at three hours of rinsing in order to make sure y'all go all the acid off the specimen. PS: There is a "Mineral Cleaning & Preperation" forum down the bill of fare a flake. People who do a lot of this sort of stuff tend to read that forum and respond to queries - more and so than are likely to pick up on a query placed in this forum. Thanks! Alan
5th Jun 2005 08:03 UTC John Steenbergen
Hey thank you Alan,y'all know something? I have never ever looked into this role of the forum and did'nt even know this was there. Now i can see that all the answers are in that location! How dopey tin i go.
2nd Jul 2005 19:18 UTC Ted French
John, I employ a 50%/50% water and muriatic acrid, It cleans the copper very brightly. Then I neutralize the acid in baking soda. After they dry out, I coat them with clear spray paint. After that they volition stay vivid for many years. Ted French
3rd Jul 2005 20:05 UTC Rob Woodside
Savages!!! You are ruining adept coppers sticking them in acids. Fortunately there are a lot of well crystalized copper specimens that aren't wrecked with acid. Your activities merely make these more valuable. I used to think that Michigan silvers were acid eaten, indistinct blobs; until I got an education at the Seaman Museum. There is petty more disappointing than to see a harshly etced copper or silver.
27th February 2012 20:15 UTC david towle
We use a very old method to clean native copper nuggets. All the one-time collections in Michigan museums were originally cleaned with ketchup. The proccess I employ is to put the nuggets in Muriatic acid for ten fifteen minutes to remove any iron, dirt and calcite. then rinse in several pails of clean water and bankroll soda, then to nuetralize the resido acid. You tin air dry them at this point to check them out or you can go to the next step. Take an ice cream pail and empty one or ii bottles of any ketchup into the pail. Put the nuggets into the ketchup, making sure they are all covered. Get out them in there for four,5,6 days. I remove them with a large spoon with the holes in it. And so rinse off the kechup and allow them dry off. The copper will wait just similar the first day they were made. A bright and natural shine. A few may some times oxidize back to a fuzzy dark-green. These will not clean upward because of the mix of impurities in the copper. This ketchum method will keep your copper specimens in a like new natural condition for many years. I have some that we cleaned twenty years ago and they still wait like they were just cleaned yesterday! If some tarnish and you don't like the look through them back in the ketchup for a few days and they will exist back adept as new. While the nuggets are in the ketchup, encompass the pail so the ketchup doesn't dry out out. The ketchup can be reused till it starts turning a brownish blackness color or you need it for your hambergers. Yuk. The ketchup tin be thrown out usually as there is no harmfull or dangerous chemicals used. The muriatic acid can be thrown out following the instructions on the canteen. I like to nutrallize it with baking soda before getting rid of it. Also we don't use vinigar as information technology can etch the copper. Making a valuable specimen worthless. So relish the ketchup cleaning proccess, it works. Dave
8th October 2013 01:32 UTC Dan the 2d
I am new at this only... I take several big copper nuggets, the biggest 30 lbs and the smallest 5.five lbs One of the pieces is copper and quartz. (sort of like a pokey birds nest) I used muriatic acid on all of them (I did not dilute the acid), some came out quite nice, and just needed some buffing. Others came out all black and red. Saturday in the acid for 5 hours, and and so out and into baking soda and water for 15 hours. I am having problem getting the smooth and luster and I deceit figure it out. I've tried vinegar and salt (short period of fourth dimension) and I besides used tarnex (brushing on) afterward the wash in water, copper looks slow once again. I am starting to think, the merely style to get proper smooth is with a wire brush. (Which is tough labor and time consuming) I accept done lots of research, only I have non found a clear cut answer. Anybody who can help or give advice, I would greatly appreciate it.
8th Oct 2013 01:36 UTC Reiner Mielke Expert
Copper that has a lot of arsenic in it cannot be cleaned with chemicals. This is not all that uncommon with Michigan copper, and is probably what you have.
8th Oct 2013 02:28 UTC Paul Brandes 🌟 Managing director
Unfortunately Dan, leaving your copper in muriatic for five hours probably damaged it beyond repair now. Usually, one never leaves copper in muriatic (if it is even used at all) for no more than peradventure 5 minutes to strip off carbonates IF there are no crystals visible. If one suspects whatsoever crystals so much milder methods must be used. Some other options include vinegar (over again lookout man the fourth dimension it is in) and yes, even ketchup.
8th Oct 2013 xiv:05 UTC Dan the second
Wow 5 mins only in the acid, I volition have to notation that, thank you. How long? In ketchup? Or common salt and Vinegar? I do take a crystalline sample. (it came out black from being in the acid later long while, I checked on it virtually every xv mins, with little noticeable alter to its surface. Any guidance is appreciated. I think i merely had one piece really go ruined from the acid, considering it etched the metal to the point where you could see what it was made of, lighter and darker pieces of copper. again cheers for the help in advance, this has certainly been a learning procedure.
8th October 2013 14:21 UTC Dan the 2d
I want to add a note almost of my copper pieces, were covered in oxidation and blood-red and black, before I even put them in the acid. This wasn't simply a nugget with just oxidation, lots of hardened dirt and debris. Some of the pieces retained crevices that had large chucks of greenish oxidation even after beingness in the acid.
8th Oct 2013 14:35 UTC Dan the 2nd
Okay more questions. Every bit mentioned earlier, I am a newbie and have a cracking bargain of learning to practise. For the time to come: i. Should I take a wire castor to it first, cleaning clay and debris and surface oxidation. (skip if fairly clean already???) 2. Then v minutes in acid (hydrochloric acid)? later that's consummate, 3. I permit it soak in blistering soda and water for 15 mins? (iii times longer than acrid soak) iv. And then theoretically, I am fix for clear coating? (right?) cheers for your time - Dan
Note: this has never been the case for me, normally I have to retouch information technology upwardly with wire castor
eighth October 2013 14:42 UTC David Von Bargen Manager
"Should I take a wire castor to it first," - A wire brush could scratch the copper. If you have any decent crystals on the specimen, you will ruin the value. Hosing it off is meliorate (too pressure washing if you have the equipment)
8th October 2013 fifteen:24 UTC Keith A. Peregrine 🌟
I use a dish scrubber to remove every bit much dirt every bit possible after letting the rock soak in water for a while. There are some with very stiff bristles and others with soft. I utilise both depending if there are any visible crystals present, copper or otherwise. Stiff ones are good for softening and removing tough grime, but they can impairment crystals or soft textile. In that case soft bristles are preferred. Equally for cleaning copper, what I've encountered is when using dilute muriatic acid, the copper volition quickly tarnish from collected from most Keweenaw dumps, a few don't. I've always attributed this to impurities within the copper though I have never tested that idea. The copper generally tarnishes to a irksome brown or cherry-red brown color, sometimes well-nigh black. A soaking in white vinegar usually brightens it up, but as it dries it dulls once more. I have found that the quicker you dry the copper, the more of a shine is retained. Even so I've not succeeded very well in keeping a good shine. Copper Brilliant is supposed to coat copper to preserve the shine, simply I've but used the liquid version, didn't work. Supposed to utilize the powder Copper Brilliant. Promise to obtain some soon when I visit the UP once again this weekend. Curiously, freshly cutting copper seems to retain its polish easily, which makes me retrieve that there has been some reaction with muriatic acid and vinegar. I've discovered that thin to wire copper can thus be etched or even dissolved in muriatic acid. Seeing that others have fabricated this ascertainment before, I need to experiment with other acids in removing calcite in the hope of non dissentious the copper or other desirable minerals present. I can't say for sure, but I'yard getting the impression that muriatic acid removes the luster of Prehnite, leaving it wearisome. Some Microcline colour appears washed out, though I tin't exist certain that it happened during crystallization.
eighth Oct 2013 16:34 UTC David Von Bargen Manager
A lot of the Upwards locals apply sulfamic acid to clean copper. Seems to be a lot gentler than muriatic. It is available in Upwards rockshops.
8th Oct 2013 17:20 UTC Ronnie Van Dommelen 🌟 Manager
I concord with Rob that etching in HCl can ruin nice copper specimens. I tend non to make clean mine at all, though the recipe below makes me want to try it... In the March-April 1972 MinRec, Yedlin on Micromounting column, he describes a recipe to avert the carving. You demand a 'not-porous vessel', 1 part lye (sodium hydroxide), three parts Rochelle salts (potassium sodium tartrate), and twenty parts distilled water. Suspend the copper, by a copper wire and dowel, from the top of the container. Shortly the liquid will turn blue. Lift the specimen a few times to check on it. When ready, rinse. Take proper safety precautions with the lye. I accept not tried the recipe or know of anyone who has, so I can't annotate farther. I would love to hear if someone does endeavour it.
8th Oct 2013 17:20 UTC Dan the 2d
Keith, I utilize a wire brush, attached to a power drill, seems to take softer bristles.(does non scratch too much) Does a practiced job, and keeps the shine long enough for articulate blanket. Nonetheless, if y'all have a crystalline / pokey bird nest shape, its hard to get to the interior edges. I think your right most the U.P. copper, some of it shines nifty, simply others are stubborn and return to dull color, time and fourth dimension again, Wire brush, seems to fix this. but its ALOT of work. and makes it hard to get into nooks and crannies.
8th Oct 2013 18:54 UTC Mickey Marks
Place the copper in a bathtub and fill with hot water. Take a sponge and some soap and scrub the copper until clean. But first, do non forget to remove his uniform and badge.
8th Oct 2013 23:21 UTC Scott Sadlocha
I have been using a watergun on some of my copper, but it is a laborious process that usually takes multiple sessions. Personally, I HATE what HCl does to copper. I learned this the difficult way, soaking a overnice Phoenix Mine copper in dilute HCl for just a little while. All defined crystal edges were damaged, and the piece had that typical "burnt" look common to acid soaked copper, and some of the faces were hackly. Later on spending fourth dimension looking at many copper pieces now, I tin unremarkably quite easily see a slice that has been acid soaked. Everyone is different, but my preference is a natural looking piece, patina and all. To me, bright, shiny copper is unnatural and that is not how I want my pieces to look. I am nevertheless looking for a good method to make clean. I am heading up to the UP in a couple days, and I am going to stop in to some of the shops of there to catch some sulfamic to try it on a couple representative pieces. I have found vinegar to piece of work decently, but once more it restores smooth. If I have a piece that I admittedly don't want to lose the patina, I accept found mechanical cleaning the only means (watergun and picks, soft brushes, etc.)
9th Oct 2013 01:31 UTC Dan The 2d
Hi over again, I have a 10 lbs quartz and copper piece, information technology took the acid bathroom, and at present is blackness. I have removed almost of the black with the wire castor, just there is still a lot I cant get to. How do I get rid of the rest of the black removed? (Hi powered water washer?) or is it hopeless? Help me out if you tin, I am looking to clear coat before long. thank you
9th Oct 2013 04:40 UTC Rob Woodside 🌟 Manager
Clear blanket will just add to the harm of an acid eaten copper, but it could make a lovely decorator slice. The decorator market is nowhere near as fussy as the specimen market.
9th Oct 2013 13:57 UTC Dan the second
Rob, I hear you, simply are yous saying a blackened, specimen with 0 cleaning volition sell better?(I would tend to largely disagree) (check out ebay and wait at non cleaned versus a dingy and oxidized) Also rob, seems that my piece was not damaged by the acrid, because of the black coating. I wish I could bear witness you my before and afters. Visually my pieces took 20 steps up and kept nigh of its natural wait, just with a fiddling extra shine. as well if y'all don't clear coat, your going to loose most of the smoothen. I desire people to walk in and say wow, whats that.
9th October 2013 fourteen:03 UTC Dan the 2nd
I am re-posting my question, Hello over again, I take a 10 lbs quartz and copper piece, information technology took the acid bathroom, and now is blackness. I have removed most of the black with the wire brush, but there is still a lot I cant become to. How exercise I get rid of the rest of the blackness removed? (Hi powered water washer?) or is information technology hopeless? Help me out if you tin can, I am looking to clear glaze presently. thank you
9th Oct 2013 15:03 UTC Keith A. Peregrine 🌟
Dan, In cases where the copper turns blackness, I place it in white vinegar. Usually this removes the black, merely in many cases it turns dark again, though non black. One way to minimize this is to identify the copper nether a heat lamp. The longer water stays in contact with the copper, the greater the nighttime tarnish. Rarely do I want to have a bright copper, but want to betrayal information technology. The reason I use muriatic acrid is to dissolve (etch) the calcite. In many cases I have no idea what lies beneath the calcite. This by Copper Country Retreat I concluded up with a neat slice containing flecks of silver and copper on height of gemmy epidote. Since there was a lot of calcite, I let it sit in the dilute hydrochloric acid foe over an hour. None of the copper was crystalline, simply flakes. However, I shall bite the bullet and use another acrid to etch away the calcite in the time to come. If my impatience can handle information technology....
9th Oct 2013 20:04 UTC Rob Woodside 🌟 Manager
Dan, the specimen marketplace pays kilobucks for good xls, but aught for an acid blackened piece, no matter how shiny or coated it is. The specimen marketplace is brutal on prissy untreated Cu specimens with no xls. (Copper skulls excluded) The is also a strong monetary bias for specimens with a mine locality.
27th Mar 2016 06:46 UTC PeterMac
I as well accept some nice pieces given to me from a Queensland mine. All of the suggestions accept relied on acids of 1 form or other; from very strong chromic, sulfuric, hydrochloric (Muric), acetic (vinegar), mild citric (tomato). The stronger the acid, the more oxidizing, which can issue on blackness copper oxides. The green is residue chlorides from salt, tap water or hydrochloric acids. Significant carbonates tin can crusade bluish or green staining, but the conditions are very specific. A mild acid, costless of chlorides, over a longer fourth dimension is preferred after the "dirt" or gange is removed. I use to use Coke, which is about iii percent phosphoric acid, low in chlorides. Rinse, and leave immersed in water for7 days before exposing to air. If you lot desire to keep just for visual purposes. Give a light spray of Mr Sheen, a mixture of non oxidizing light oils to reduce later oxidation. (I been told different cokes now have different formulations... So you may have to experiment)
27th Mar 2016 12:43 UTC Keith A. Peregrine 🌟
With added input from friends and previous results, I take now gone over to Sulfamic acid. Reason being, Muriatic acid will compose some copper. While taking considerably longer, Sulfamic does not set on the copper. The acid is used to remove calcite which generally covers areas of interest such as vugs. Acid is also useful in quick cleaning, that is not much more than than a dip, rinse, scrub, and soaking in water. Ane technique I am using and even so experimenting with, is using compressed air to blow off water on a specimen, and so placing the specimen under a oestrus lamp for ten minutes or so to evaporate off whatsoever remaining moisture. This has given me skilful results in preserving the 'brilliant' luster of copper. As Rob points out, if you lot know you have copper crystals, do not use any acrid bath!
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