Blackening of copper. Blackening copper at home video. Homemade selective coatings. Methods using chemical reagents About the use of sulfur ointment
The easiest way to blacken copper is with ammonia vapor (ammonia). A thicker color is obtained if the product (wire is pre-soaked in a solution table salt few hours).
A review of the Internet showed. that this is not the only method. I found the most information on the forum of ship modellers: http://shipmodeling.ru/
The scale of copper products and the desire to obtain a good and durable effect bring us closer to ship modellers. I chose those recipes that forum participants give as proven in practice and for which, in principle, you can find materials:
1. Buy special compounds for blackening (bluing) metal at a jeweler's store or at a hunter's store. (Not cheap!)
2. Prepare black mordant for copper: Dissolve copper sulfate in warm water. The solution needs to be saturated, i.e. add vitriol until it still dissolves. Add ammonia until the mixture becomes bright transparent Blue colour. The product to be treated must be immersed in the solution for several minutes, removed and heated until the part turns black.
3. Spread with sulfur ointment and put in a warm place (on the radiator) for several hours. However, they say that the coating is not very stable.
4. Prepare a simplified version of the liver sulfur solution, in which potash is replaced with soda ash. Here's more detailed description process: " A ceramic bowl with a handle, like a pot. In 150 ml of distilled water I dissolved two tablespoons of soda ash (bought at the store household chemicals in similar packaging washing powder) brought it to a boil and began to add colloidal sulfur (bought at a flower fertilizer store), also two or three spoons. The yellow solution began to darken and after 7-8 minutes acquired Brown color. Either I didn’t calculate the grams in the spoon, or the water boiled away, but the required liquid in my opinion turned out to be not enough and I added more water by eye and boiled it some more. The final liquid turned out to be slightly yellowish-greenish in color. At the bottom thick layer yellowish sediment. Carefully drained the resulting liquid.
My guns are made of lead covered with copper. Store-bought products did not provide a permanent coating, and this cloudy liquid gave my copper products a radical black color within 1 minute. The coloring is stable, unlike my store-bought ready-made reagents, and uniform. Can be polished with a brush, but becomes dark dark gray and begins to shine."
5. And finally, one more recipe (although there is only a link on the forum, no one has used it): Dissolve 4 g of caustic soda (caustic soda) and 4 g of milk sugar in 100 g of water, boil for 15 minutes, then, with constant stirring, add 4 g of saturated solution in small doses copper sulfate. Well-cleaned copper products are immersed in the hot mixture. Depending on the duration of action, they will acquire different colors - from gold, green to complete black.
Milk sugar is a baby food product. Here is a link to the manufacturer (distributors include addresses of stores in Russia).
Copper is a metal that has low activity and for this reason is often used for decorative purposes. Copper is used to make jewelry, home decoration, art, furniture and much more. The metal surface oxidizes under the influence of oxygen, but due to its low activity, this may take decades. The consequence of this reaction is patina - a surface film that most often has a greenish tint. Patina prevents the metal from being damaged, so it is important to know how to blacken copper at home.
Copper before and after blackening
There are two types of reactions that lead to the formation of films on the surface of copper:
- oxidation - the process of formation of oxides and oxides, elements containing oxygen;
- patination - a film is formed under the influence of sulfur and chlorine.
If you dip a copper piece in a solution designed to create a patina on its surface, it will immediately be transformed and, while sparkling new, will look like an antique. There are two main types of methods by which this effect is achieved, some are based on improvised means, while others require chemical solutions. They can be dangerous, so you need to work in compliance with all safety regulations. The room must have a fume hood.
Before you start blackening, you need to prepare the metal: clean, degrease, rinse and dry. For drying, do not use the towel wiping method. This can lead to fabric residues on the products, water in the recesses of the relief, and damage to the decorative part. You can use sawdust for this purpose.
Methods using chemical reagents
One of the most common methods is the use of liver sulfur. It can be purchased at the store or prepared at home. To do this, mix powdered sulfur with potassium chloride in a ratio of 1:2 and put it on fire in a tin can. After a few minutes, the powder will melt and, after 15 minutes, will sinter, its color becoming dark brown. This process may be accompanied by a flame, which does not need to be put down.
The first method, which uses liver sulfur to blacken copper, is as follows: 10–20 grams of powder are dissolved in one liter of water, or two to three grams if it is necessary to obtain a less intense color. The copper product is dipped into the solution until the color changes, then it is removed, washed and dried. The color turns out to be brown-gray and its shades.
The almost black color of the product is obtained by heating, after treatment in a solution of liver sulfur with water and the addition of ammonia. Alcohol must be added to the saturated solution until it turns transparent blue. A coin or copper jewelry is dipped into the solution and then heated until it turns black.
Another method for obtaining black-brown color is as follows. Platinum chloride is applied to the product, for example, wetted with a brush. If the solution is not acidic, hydrochloric acid is added to it.
A red-brown patina can be obtained using a one-to-one mixture of copper sulfate and zinc chloride. The mixture of powders will need to be mixed in the same amount of water and the copper product should be immersed there for a few minutes.
Patination of copper with ammonium sulfide produces a black color. The substance (20 g) is diluted in a liter of water. You can either dip the product into the solution or apply it with a brush. A reaction occurs on the surface, resulting in the formation of copper sulfide. If you heat the plate before patination, then depending on the temperature, you can adjust the shade of the resulting color.
Blackened copper product
Another way to obtain black color is to heat a coin or jewelry at a high temperature in a solution of ammonium persulfate (9.25 g/l) and caustic soda (50 g/l). The temperature should be 90–95 degrees, the warming time should be 5–25 minutes. Repeat two to three times until the desired effect is achieved.
A light brown patina can be obtained by covering the product with the following solution:
- 124 g/l sodium dichromate;
- 15.5 g/l nitric acid (1.4);
- 4.65 g/l of hydrochloric acid (1,192);
- 3–5 g/l 18% ammonium sulfide solution.
Apply the newly prepared solution with a brush, leave for four to five hours, rinse and dry. The procedure must be repeated three times.
Green patina is obtained by two main methods:
- Using a sponge, the copper surface is lubricated with a low concentration solution of copper nitrate with the addition of table salt. After drying, lubricate it with a solution containing: 94% table vinegar, 5% ammonia, 1% potassium oxalate. After drying, lubricate first with the first and then with the second solution again. The procedure is carried out until the copper reaches the desired color. After painting is completed, the surface is rubbed with brushes.
- In the second method, the surface of the copper product is rubbed several times with oleic acid. This produces a dark green substance on the surface - oleic copper. Over time, the shade changes to light green, as under the influence of moisture and oxygen, oleic copper is converted into carbon dioxide. A solution of five grams of potassium permanganate and 50 grams of copper sulfate gives a golden-brown patina. Dilute in one liter of water and heat to a temperature of 70–80 degrees. Lower the product and hold until the desired color is obtained.
To obtain a highly wear-resistant coating that protects the metal from corrosion, take in grams per liter of water: 50–70 berthollet salt, 40–50 copper nitrate, 80–100 ammonium chloride. The product is placed in a bath with a heated solution for 10–15 minutes. The color ranges from brown to olive.
You can get an amazingly beautiful golden patina. To do this, take 0.6 grams of copper sulfide, 180 g of milk sugar and the same amount of sodium hydroxide per liter of water. Aqueous solutions of the last two components are prepared separately and only then mixed. Copper sulfide is added only after the mixture has boiled. Place the product in a solution heated to 90 degrees for a quarter of an hour.
Getting patina with an egg
A black-brown patina can be achieved using a boiled egg. The effect is the interaction of the metal surface with sulfur, which is released in the yolk at high temperatures. To do this, you must first boil the eggs, and only then add the copper product to the water. Depending on the size of the product you will need different quantities eggs
Another option. After the eggs are hard-boiled (10 minutes), they must be removed from the water and cooled. The peeled eggs are crushed and placed in a container with a wide bottom, and copper is also placed there. The container is closed for 20–30 minutes or more, depending on what color you want to get: for more long time the product will become darker. The main advantages of this method are simplicity and accessibility. The main disadvantage is that the effect most likely will not be long-term and the coating will come off.
Patina has excellent properties. For example, in numismatics, the value of an item depends on how uniform it is. Artificial turf cannot replace natural turf.
If the patina has a uniform structure and evenly covers the surface, then it is better to preserve it on the product. This especially applies to antiques and coins. To upper layer is not damaged, it is necessary to care for the product and handle it with special care. Do not clean with abrasive products or tools. And it’s better not to touch the product with your hands.
But if it has chips, stains, looks ugly or is not uniform, then such methods will do just fine. If you want the patina to lie evenly, then old layer must be cleaned to a metallic shine.
Scunc 10-02-2015 14:14
Health and success to everyone!
Please share your experience of who inked the copper, I used the search, but I want to ask who personally did it.
Is it possible to obtain a stable (cannot be washed by hands) black color and with what?
Preferably from available materials...
Max_CM 10-02-2015 14:19
You can erase everything.
take the copper in your hands, run hot water from the tap, and rub the copper with ointment under the stream.
sansem80 10-02-2015 14:22
quote: Originally posted by Max_CM:
... from the tap, hot water, and rub the copper with ointment under the stream.
Oh, how. Otherwise, I applied this ointment to dry and cold copper, but nothing really inked.
Doesn't the ointment wash off under running water? What should I rub it with? A rag?
vladimir c 10-02-2015 14:30
I tried simply rubbing it with my finger on cold finely dispersed sulfur (sold in gardening stores) - it turned black.
Vitaly B 10-02-2015 14:36
quote: Originally posted by Max_CM:
At the nearest pharmacy Sulfuric ointment 3kop price.
I did it differently, spread a layer on the hot body table lamp I put it down, or blow it with hot air with a hairdryer and everything turns black, not bad, in 3-5 minutes, although I did it on silver, copper should darken faster. Afterwards, wash everything with acetone or soap...
------------
Best regards, Vitaly.
www.vitaliknife.ru
Scunc 10-02-2015 14:37
Here I use sulfur ointment and ink, it turns black well, but the ink is easily erased completely, I wonder about the jet, what does it do?
Max_CM 10-02-2015 14:44
It just heats it up, it’s more convenient for me, just with my fingers, Vitaly puts it on the lamp, it doesn’t matter how the main thing is to heat it up.
Visiter 10-02-2015 14:45
Sodium thiosulfate (10 ml ampoules from the pharmacy, inexpensive) + any acid (I made it with acetic acid). Pour thiosulfate, add acids until the color of milk and the smell of hydrogen sulfide are obtained, lower the copper (bronze, brass, etc.). Color depending on exposure, quite quickly.
They gave me good advice on sulfur ointment; I applied it cold, but it didn’t help.
niks78 10-02-2015 15:07
When I stained the oak tree in ammonia and put the copper tire on it, it turned black with a blue tint. I haven't tested the durability
vityuxa 10-02-2015 15:43
quote: here it is excellent remedy blackening.1470.0 rub. for 90 ml. Six, or even seven funfairs of vodka! Question about durability, is it worth it? how about erasability?, from time immemorial it was inked with sulfur liver, (since the 16th century) since it has come down to the present day, the bicycle was not invented. I tried. But you definitely need to take Potash (POTASSIUM carbonate), specifically, with baking soda (SODIUM carbonate) the effect is not the same, it is less stable, and the coating is time-to-time. That’s not bad; coat the cleaned, fat-free part with a brush with nitric acid, the amber is not comme il faut, but not really, in the common fund at the station it’s worse. And immediately heat it up, you can get a very diverse color, but it takes some skill. With both acid and sulfur liver, the coating can only be erased with fine sandpaper or sanding paste. I will sign every word, since I myself was bothered by this ink idea.
Nestor74 10-02-2015 15:53
quote: http://www.medwed-hunt.ru/Good...atalogBegin - here there is an excellent blackening agent.
Really
Look for BrassBlack in gun stores - I haven't seen anything better yet. The effect is immediate. Blackens copper, brass, bronze, silver. What other sulfur ointment? We must keep up with the times. All my works are patinated with this liquid.
Trident8 10-02-2015 16:00
Sulfur liver: mix sulfur (taken from a veterinary pharmacy) with soda 1:1, stirring until brown, dilute slightly with water - and off you go, cheap and cheerful.
niks78 10-02-2015 16:39
and when I stained the oak with ammonia, I put the copper bus down and it turned black
Androniy 10-02-2015 16:53
I wanted to darken the copper coin only slightly, but the slightest application of sulfur ointment immediately resulted in a dark brown coating. I found a solution - add a little sulfur ointment to a large amount of Vaseline. Then I applied it to the fabric and rubbed it vigorously. The result was a light brown patina.
Max_CM 10-02-2015 17:03
quote: Originally posted by vityuxa:
1470.0 rub. for 90 ml. Six, or even seven funfairs of vodka! Question about durability, is it worth it? how about erasability?, from time immemorial it was inked with sulfur liver, (since the 16th century) since it has come down to the present day, the bicycle was not invented. I tried. But you definitely need to take Potash (POTASSIUM carbonate), specifically, with baking soda (SODIUM carbonate) the effect is not the same, it is less stable, and the coating is time-to-time. That’s not bad; coat the cleaned, fat-free part with a brush with nitric acid, the amber is not comme il faut, but not really, in the common fund at the station it’s worse. And immediately heat it up, you can get a very diverse color, but it takes some skill. With both acid and sulfur liver, the coating can only be erased with fine sandpaper or sanding paste. I will sign every word, since I myself was bothered by this ink idea.
www.chip-dip.ru sera fic knows it, I’ve been to all the pharmacies, it turns out it’s only available where the medicines themselves are prepared in production facilities,
I begged for a teaspoon, ran home and quickly cooked!
I came across a stainless steel ladle and the blackening still remains on it! It stinks! I thought the neighbors would call the Ministry of Emergency Situations right now!
It inks great, I don’t remember the stability on copper, but it washes off easily from silver, and unfortunately, this brew is not stored, it decomposes, you have to brew it again every time. In!
hunter1957 10-02-2015 18:51
quote: Yeah! about two or three years ago I got confused with sulfur liver, potash at www.chip-dip.ru sulfur fic knows it, I went to all the pharmacies, it turns out it’s only available where the medicines themselves are prepared in production facilities, I begged for a teaspoon, ran home and quickly cooked! A stainless steel ladle, the blackening still remains on it! It stinks! I thought the neighbors would call the Ministry of Emergency Situations right now! The ink is great, I don’t remember the stability on copper, but it wears off easily on silver, and unfortunately, this brew is not stored, it decomposes, you have to brew it again every time. In!In Ruskhime it will be cheaper to take chemistry.......
Scunc 10-02-2015 20:45
Is this liver stored for future use?
vityuxa 10-02-2015 21:29
quote: You have to cook it again every time. In!The solution sits in the refrigerator for a month, the secret is simple, just right up to the neck, just try with a “slide” so that it pours out from under the cork when twisting, it works fine, although when it’s cold it’s slower. The boiled powder will lie as long as you like, without moisture, I also put small bags of silica gel for medicine in my vitamin bottle. And there are also some nuances: first melt the sulfur and pour it out, well, it stinks, of course, the main thing is that it doesn’t dry out, it’s not scary, but it stinks more, and only then slowly sprinkle in the potash and stir. I made 1 sulfur 1.5 potash. A good correct powder only came out after 4 times, then the sulfur did not dissolve, then it was kind of shitty, in lumps. Well, fuck it, you have to do it and that’s it! You can’t stop it...
i_vb 10-02-2015 22:16
I don’t make knives en masse, but I do a lot, with copper elements even less often. I use the aforementioned BrassBlack. The same applies to cupronickel. A bottle costs 700 rubles, not 1600, at least in Moscow. I don’t know how long it will last, but 3 years, about 20 different parts - a third of the bottle. This cannot be removed with a sheath or hands, but with a zero - it’s easy, however, like the vaunted liver.
PySy: If there is a cat in the house, throw a copper or brass bolster into his toilet for a day, old bronze I guarantee it. Moreover, even with a zero you won’t be able to pull it off right away. But - a little divorced. Verified.
vityuxa 10-02-2015 23:00
Here's from the chemists: they are certainly impartial. http://chem21.info/info/18373/ Products made of copper and its alloys can be painted in colors from gray-black to black-brown by oxidation in solutions of ammonium sulfide or sulfur liver. The so-called liver of sulfur is a mixture of various potassium polysulfides with potassium thiosulfate. Sulfur liver is obtained by fusing sulfur with potash for 15-20 minutes. Various recommendations suggest fusing 1 part (wt.) of sulfur with 1-2 parts (wt.) of potash (potassium carbonate K2CO3). Sulfur is melted in a porcelain cup, then dry potash is gradually added to the melt with constant stirring. When air enters, interaction occurs between the components of the melt and a brown viscous mass is formed
If, when preparing sulfur liver, instead of potash, soda (sodium carbonate) is fused with sulfur, then light gray films will form on the surface of the silver treated with such a preparation.
Scunc 11-02-2015 06:57
As I understand it, it’s ordinary sulfur, i.e. yellow pieces?
RashchektaI 11-02-2015 08:26
Well, why bake something? When there is ready-made pure thiosulfate.
Scunc 11-02-2015 11:35
quote: Originally posted by RashchektaI:
Well, why bake something? When there is ready-made pure thiosulfate.
They add acid to it and that’s it? They just don’t write which one and how much(
I have nitrogen 60 and vinegar 70, will that work?
Scunc 11-02-2015 12:42
Interesting, have you tried it?
Nestor74 11-02-2015 13:01
quote: Interesting, have you tried it?
quote: Works on almost all "tsvetnina" tested
I wasn't too lazy to count. I treated 100 knives with this liquid, I didn’t use half of them (!!!) 100
How else can you be convinced?
If you just smear it with a thiosulfate solution, it won’t turn black at all. barely... it's not work. Just frustration.
vityuxa 11-02-2015 13:25
quote: Vityukha is clear, it’s more important for him to buy vodka, he’s cringing))No San, I’m not greedy, I’m ideologically fucked up, and I don’t believe in anything until I figure it out myself, or I don’t do it, but I’ll keep doing it until I succeed... And my sons will buy vodka if they do, no problem .
Scunc 11-02-2015 17:06
BrasBlack is interesting, I just stopped at first by the price and availability, then I looked... sulfur is in bags at work, thiosulfate is sold in the pharmacy, i.e. In any case, some hemorrhage. You can't just buy it in a store(
But I have identified three main options for myself, so I will move in this direction, whichever is the first available will be where I will start)
And thanks for the advice! I needed personal opinions.
L.E. 11-02-2015 18:04
quote: Originally posted by i_vb:
The bottle costs 700 rubles
Please tell me where you got it in Moscow?
GM63 11-02-2015 19:50
I still don't understand about BrasBlack. Religion doesn't allow it? Where else with goodness?
There is no need to add any stink or acid.... I unscrewed the cap, dipped the brush, anointed it, twisted it... No dancing with a tambourine...
Vityukha is clear, it’s more important for him to buy vodka, he’s cringing))At least that's enough.
How else can you be convinced?About thiosulfate. He works in hot water with the addition of hydrochloric acid. It is needed as a catalyst. WITH acetic acid it won't work. I already checked)))
The product must be immersed in a hot solution for several minutes. Those. This option is not convenient for us. You can’t put a ready-made knife there, but you can blacken the part separately, but then during installation you’ll tear it off, scratch it...
Alexander.
Somehow you misunderstood me apparently
Scunc 11-02-2015 21:17
Sodium thiosulfate is a prescription drug(
Scunc 11-02-2015 21:24
quote: Originally posted by GM63:
Alexander.
I didn't even understand. On the contrary, I say that I am against this collective farm with sulfur acids and the stench in the kitchen.
But just to buy a special liquid “Noirit” in Nozhinsk for 400 rubles per 100 ml. and use it, because it blackens and ages almost any metal color, and brass-copper generally looks black.
True, when ordering, you need to remind them to check the packaging. Last time I ordered, half of it leaked out.
Somehow you misunderstood me, apparently
i_vb 12-02-2015 12:24
quote: Please tell me where you got it in Moscow?
I wrote that I took it a long time ago - two years ago. 560 rub.
Last time I saw it in a hunting store on Kalanchevka for 750 rubles. before New Year.
If I don’t forget, I’ll come in and have a look.
And so - in hunting stores. The idea with the cat was ignored in vain - it works for free!
GM63 12-02-2015 01:00
quote: Originally posted by Scunc:I'm looking for now (BIRCHWOOD CASEY 15225 BB2 Brass Black Metal Touch-Up) that's what it's called correctly.
What to look for here...
Any gun shop has it.
RashchektaI 12-02-2015 08:31
quote: Originally posted by Nestor74:I still don't understand about BrasBlack. Religion doesn't allow it? Where else with goodness?
There is no need to add any stink or acid.... I unscrewed the cap, dipped the brush, anointed it, twisted it... No dancing with a tambourine...
Vityukha is clear, it’s more important for him to buy vodka, he’s cringing))
I wasn't too lazy to count. I treated 100 knives with this liquid, I didn’t use half of them [b](!!!) 100At least that's enough.
How else can you be convinced?About thiosulfate. It works in hot water with the addition of hydrochloric acid. It is needed as a catalyst. It will not work with acetic acid. I already checked)))
The product must be immersed in a hot solution for several minutes. Those. This option is not convenient for us. You can’t put a ready-made knife there, but you can blacken the part separately, but then during installation you’ll tear it off, scratch it...If you just smear it with a thiosulfate solution, it won’t turn black at all. barely... it's not work. Just frustration.
What an apologist you are for Brasblek. When you need to make a hundred knives and the cost of one costs 30 rubles, then it’s easier to buy, but when you make one knife a year with copper, it’s doubtful. As for the acid, I didn’t try it well, but it works great with vinegar essence. BUT nitrogen or sulfuric acid is preferable.
111StS111 12-02-2015 10:04
Blackening agent for bluing Raven3. Blackens steel, cupronickel, copper, bronze, brass. I haven't tried stainless steel. Doesn't take silver. The coating is quite durable.
Costs 200 rubles.
The easiest way to blacken copper is with ammonia vapor (ammonia). A thicker color is obtained if the product (the wire is pre-soaked in a solution of table salt for several hours).
A review of the Internet showed. that this is not the only method. I found the most information on the forum of ship modellers: http://shipmodeling.ru/
There are actually several ways to achieve that gorgeous brown patina on your brass or brass. You can use chemicals or more environmentally friendly methods. Some chemicals may be caustic and should be used with caution. Then of course there are the more common ones chemical substances, such as "Liver of Sulfur", "Black Max" and antique solutions containing iron nitrate. It's environmentally friendly clean way oxidation of copper and silver. The process takes four to six hours.
Using Homemade Ammonia on Copper and Brass
A small, shallow dish on which to place your metal or jewelry. The container or bag should be large enough to hold a small dish plus hard-boiled eggs with room for storage. Two or three hard-boiled eggs. . Place your jewelry or metal pieces on a small dish. The egg should not touch metal or jewelry. You'll be tempted to look, but don't! Using household ammonia vapor to oxidize metal is actually quite simple and is an inexpensive way to oxidize copper and copper.
The scale of copper products and the desire to obtain a good and durable effect bring us closer to ship modellers. I chose those recipes that forum participants give as proven in practice and for which, in principle, you can find materials:
1. Buy special compounds for blackening (bluing) metal at a jeweler's store or at a hunter's store. (Not cheap!)
2. Prepare black mordant for copper: Dissolve copper sulfate in warm water. The solution needs to be saturated, i.e. add vitriol until it still dissolves. Add ammonia until the mixture acquires a bright transparent blue color. The product to be treated must be immersed in the solution for several minutes, removed and heated until the part turns black.
3. Spread with sulfur ointment and put in a warm place (on the radiator) for several hours. However, they say that the coating is not very stable.
4. Prepare a simplified version of the liver sulfur solution, in which potash is replaced with soda ash. Here's more of the process: " A ceramic bowl with a handle, like a pot. In 150 ml of distilled water, I dissolved two tablespoons of soda ash (bought at a household chemicals store in packaging similar to washing powder), brought it to a boil and began to add colloidal sulfur (bought at a flower fertilizer store), also two or three spoons. The yellow solution began to darken and after 7-8 minutes it turned brown. Either I didn’t calculate the grams in the spoon, or the water boiled away, but the required liquid in my opinion turned out to be not enough and I added more water by eye and boiled it some more. The final liquid turned out to be slightly yellowish-greenish in color. There is a thick layer of yellowish sediment at the bottom. Carefully drained the resulting liquid.
My guns are made of lead covered with copper. Store-bought products did not provide a permanent coating, and this cloudy liquid gave my copper products a radical black color within 1 minute. The coloring is stable, unlike my store-bought ready-made reagents, and uniform. Can be polished with a brush, but becomes dark dark gray and begins to shine."
5. And finally, one more recipe (although there is only a link on the forum, no one has used it): Dissolve 4 g of caustic soda (caustic soda) and 4 g of milk sugar in 100 g of water, boil for 15 minutes, then, with constant stirring, add 4 g of a saturated solution of copper sulfate in small doses. Well-cleaned copper products are immersed in the hot mixture. Depending on the duration of action, they will acquire different colors - from gold, green to complete black.
Milk sugar is a baby food product. Here is a link to the manufacturer (distributors include addresses of stores in Russia). http://oltri.ru/page102.html
6. And this is just a recipe from the Internet: A very durable blackening of copper products is obtained if they are immersed in a saturated solution of copper metal in nitric acid and then slightly heated.
All you need is a clean whipped cream bath, a lid, and a piece of wire or fishing line to suspend your piece and clear out the ammonia. It's a little smelly, but if you're quick, the smell shouldn't be a problem. Under no circumstances should metal or finished jewelry come into physical contact with the ammonia liquid; it is the vapors that will produce this patina. First, clean your piece of brass or copper with alcohol or acetone to remove any oils or dirt so that the patina is uniform throughout the piece.
Do not touch the surface you want to patina. Pour about one inch of ammonia into a pint or quart glass jar. You can use wire or fishing line to hang metal or jewelry just below the mouth of the jar. The piece should not come into contact with liquid ammonia. Screw the lid on and wait a couple of hours. You can check this piece to see what color you want to stop.
05.09.2009
Oxidation and patination of copper, brass and bronze.
Some chemical reactions lead to the formation of oxides and oxides, i.e., oxygen compounds, on the surface of metals. This process is called oxidation.
Often chemical elements, interacting with a metal or alloy, contribute to the appearance of sulfur or chloride compounds. The process of forming such compounds is called patination.
If you dip a metal product into the prepared solution, it literally changes color before your eyes. A sparkling metal product takes on the appearance of an antique product in a few seconds.
Most chemical compounds that are used for patination and oxidation of metals are toxic and dangerous to humans. Therefore, they need to be stored in vessels with ground-in stoppers, and all work related to the release of toxic and flammable vapors and gases should be carried out in fume hood. The cabinet doors should be slightly open.
Before changing the color of the metal, it is necessary to carry out some preparatory operations. The item is cleaned and degreased, washed well and dried in sawdust. Metal art products and coins should never be wiped with a towel. A towel wipes off fragile patina films that are not secured with varnish, moisture remains in the deep reliefs, the fabric gets caught on high protrusions and can bend them. Sawdust quickly and evenly draws water away from the metal surface.
Patina from gray to black
Preparation of sulfur liver:
To prepare sulfur liver, you need to mix one part of powdered sulfur with two parts of potash in a tin can and put on fire. After a few minutes, the powder will melt, darken and begin to sinter, gradually acquiring a dark brown color. (By the way, the sintering of the patination mass gave the name “liver” in the old days - from the words “oven”, “sinter”.)
During sintering, sulfur vapor may ignite with a weak blue-green flame. Do not knock down the flame - it will not deteriorate the quality of the sulfur liver. After about 15 minutes, stop sintering. For long-term storage, crush the sulfur liver into powder and place it in a glass jar with a tight lid.
Method No. 1
Applies to:
Copper, sterling silver, and bronze or brass (light shade). Does not work on nickel silver.
Colors:
On copper and silver there is a range of shades from purple/blue (difficult to obtain) to brown-gray, gray, black. On brass and bronze - only soft golden.
A durable and beautiful patina forms on the surface of copper treated in an aqueous solution of liver sulfur.
When making a solution in 1 liter of water, add 10-20 g of liver sulfur powder. The patina obtained on metal with a solution of sulfur liver is durable and beautiful, deep black in color. But such intense coloring is not always necessary. Sometimes, to give an antique look to a copper product, it is enough to apply a light gray patina. Pour 2-3 g of table salt and 2-3 g of sulfur liver into a liter of water. Dip a copper plate into the solution. After the required gray color appears, rinse the plate with clean water and dry.
Method No. 2
To blacken a copper item, prepare a saturated solution of copper sulfate, add ammonia to it until the mixture takes on a bright transparent blue color. The copper item being processed is dipped into this solution for a few minutes, then removed and slightly heated until it turns black.
Method No. 3
The copper item to be blackened is first cleaned with fine sandpaper, after which try not to touch its cleaned surface with your fingers. Then she either plunges into liquid solution platinum chloride, or moistened with it using a brush. This solution, if it does not have an acidic reaction, is slightly acidified with hydrochloric acid.
Method No. 4
A very durable blackening of copper products is obtained by immersing them in a saturated solution of copper metal in nitric acid and then heating it slightly.
Patina red-brown
An aqueous solution of zinc chloride and copper sulfate colors copper red-brown. Mix one part copper sulfate with one part zinc chloride and dilute in two parts water. A few minutes are enough for the copper to acquire a red-brown color. After washing and drying, wipe the metal surface with oil.
Patina from light brown to black
Blackening of the metal is observed when copper is patinated with ammonium sulfide.
20 g of ammonium sulfide is diluted in a liter of water. The product is dipped into the resulting solution or poured on top and wiped with a brush. The work is carried out in a fume hood. Sulfur ions present in an aqueous solution of ammonium sulfide interact with copper ions. Black copper sulfide is formed.
The intensity of the patina on the metal can be of different shades, from light brown to black. The color is adjusted by changing the heating temperature of the plate before patination.
Patina light brown
Gram per liter:
sodium dichromate - 124
nitric acid (density 1.40 gcm3) - 15.5
hydrochloric acid (1.192) - 4.65
Ammonium sulfide 18% solution - 3-5
Apply with a brush immediately after preparation, rinse off after 4-5 hours and repeat after drying 2 times, polish with a dry cloth.
Dark brown to warm black patina
Gram per liter:
ammonium persulfate - 9.35
caustic soda - 50.0
for 5-25 minutes in a bath with a solution heated to 90 -95 degrees. rinse, dry, repeat 2-3 times
Olive to brown patina
Gram per liter:
Berthollet salt - 50*70
copper nitrate - 40*50
Ammonium chloride - 80*100
for 10-15 minutes in a bath with a heated solution to 60-70 degrees.
the resulting films have mechanical strength and corrosion resistance
Patina brown-black
Gram per liter:
Ammonium molybdate - 10
ammonia 25% aqueous solution - 7
the solution should be heated to 60 - 70 degrees
Golden patina
Using more traditional chemicals - safety first!
The ammonia smell on your piece should dissipate quickly, but if you want, you can leave the piece for a while before very carefully buffing any high spots for contrast. Of course, you can use the tried and tested, eco-friendly method of adding a patina to your metal using chemicals such as Liver Sulfur, Black Max and Antique Patina. Some chemicals can be caustic and must be handled with care, both during the patination process and when removing the chemicals afterwards.
Gram per liter:
copper sulfide - 0.6
caustic soda - 180
milk sugar - 180
a solution of alkali and lactose is prepared separately and only then poured together, boiled for 15 minutes and copper sulfide added.
place the product in a heated to 90 gr. solution for 15 minutes.
Patina golden brown with crimson tarnish and moderate shine
Remove your work surface and fold the paper because accidents happen. There is always a cup or bowl with clean water at the ready, as well as a bowl with a small amount of baking soda. Paper towels, old T-shirts, or clean rags are ready for spills and will dry your pieces after you rinse off the chemical you're using. Use safety glasses. Yes, no one likes to wear them, but are you willing to compromise your vision for an accidental splash? Have plenty of water. Make sure you have a well-ventilated area to work in. . Keep these things on hand when you are "patinaing" the metal.
After cleaning copper coins, you can create an artificial patina on them by placing 50 g of copper sulfate and 5 g of potassium permanganate per 1 liter of water in a solution, heating it to a temperature of 70-80C and holding it there until the desired color is obtained.
Green patina
The surface of copper, brass or bronze products can be painted green in various ways.
These are sponge pads that contain permanently attached micro-abrasives. They are used to highlight highlighted areas of your patinated figures.
- Cotton swabs, cotton balls or cotton swabs.
- Brass brush.
- Stainless steel brush.
- You can find them anywhere grocery store.
- This is my favorite liver shape because it is so versatile.
Method No. 1
Using a sponge, the surface of things is first lubricated with a highly diluted solution of copper nitrate with the addition of a small amount of table salt. Then, when the item dries, it is lubricated in exactly the same way with a solution of 1 part potassium oxalate and 5 parts ammonia in 94 parts weak vinegar. Let it dry again and again lubricate with the first solution; then, after drying, again with a second solution, etc. alternately until the coloring acquires the proper strength.
Before lubricating, the sponge soaked in the solution should be squeezed out firmly so that it is damp, but not wet. After painting the surface, rub the items thoroughly with hard hair brushes, especially in the recesses and crevices. After 8-14 days of work, a brownish-greenish color is obtained.
Beyond the world of simple silver and gold lies an incredible landscape of color, ready for you to experiment with: patina! Let's take a closer look at how copper patinas. First of all, you want to cook your pieces so they are free of dirt and oil for best results. This means no fingerprints, no oil. If you have access to a brine pan, now is the time to the right time for use it. If you're not worried, take Britt tape and gently scratch the surface.
Note that this will give your piece more of a satin finish, but make sure the patina has plenty of room to cling. Once it's clean, handle around the edges so you don't transfer any oils onto it. If you've ever done any studio work with copper, you may have noticed that when you heat it up, your metal will begin to change. When copper is heated, some really beautiful colors can be extracted from the metal. reds, purples and blues are all common.
Method No. 2
Things are rubbed in several stages with cloth soaked in crude oleic acid (a product obtained in stearin factories). On the surface of things, a dark green layer of copper oleic acid is first formed, which, under the influence of oxygen and air moisture, gradually turns into lighter green copper carbonate.
The process is significantly accelerated if oleic acid is first infused on copper shavings for quite a long time, and after each lubrication with such acid, after the lubricant has dried, the items are lightly sprayed (no more than a few drops!) with an aqueous solution of ammonium carbonate.
The key is to try to stop before you go too far. Try not to be too attached to a certain color until you get it because it can be frustrating sometimes. Pull the torch out slowly and you won't get huge color hits. bright until it started to cool. The best thing to do here is to experiment and see what you like and what you can stick with. When you find that a sealant is recommended.
Acrylic transparent coatings, beeswax or renaissance wax can help protect your surface and color. The ingredients for this patina are easy to find in your kitchen cabinets. Vinegar and salt, about 3 tablespoons each. Stir until the salt dissolves in the vinegar.
Copper is a low-reactive metal that is often used for decorative purposes. The article discusses the main methods for changing the color of copper at home and in the laboratory.
General information about metal color
OXIDATION of copper and brass
Copper is often used as decorative element on buildings, including in the manufacture of furniture, jewelry, objects of art. The surface of the metal enters into a chemical reaction when it comes into contact with oxygen, however, it takes several decades for it to be completely completed.
The result of the interaction of copper and air is patina - the same material, only with a greenish tint. Less common is a black or brown patina. Practice has shown that the color of patina can be corrected if it is treated by special means or methods.
Processing methods
Blackening copper with boiled eggs
Under influence high temperature Chemical reactions occur in the yolk, releasing sulfur. The interaction of our metal with sulfur gives it a dark brown color. In order for the chemical reaction to take place correctly, the steps must be performed exactly according to the instructions: first boil the eggs, then add the copper product. The number of eggs depends on the size of the copper product. They are cooked for exactly 10 minutes, after which they are removed and cooled.
Chilled chicken eggs are cleaned and finely kneaded using any available methods. Next you will need a small container with a lid and a wide bottom. Place the copper product and crushed eggs in a container. Be careful that both ingredients do not come into contact, otherwise colored spots will appear on the metal product and blackening will end in failure.
The combined ingredients are sealed in a container for 20-30 minutes. It is worth noting that the result of the experiment depends on the length of their stay together - the longer both ingredients stay in a confined space, the darker the metal you will get.
Advantages of the method: darkening the metal requires few resources: a couple chicken eggs, old iron container and gas stove. Disadvantages of the method: short-term and unstable effect. The results achieved may disappear over time or when reacting with a more aggressive chemical.
Discoloration of copper by potassium sulfide
This darkening method is considered one of the best to darken copper. Sulfide is very active substance, which should be used carefully at home. Its entry into the respiratory tract can cause unpleasant symptoms of nausea, dizziness, etc.
The metal must be prepared - wash it in warm water and soap. Otherwise, dust residues, and greasy spots will interfere with the normal course of the chemical reaction.
Next, the reagent is prepared - sulfide. It is sold in three forms: liquid, gel and solid. The shelf life of the reagent varies depending on its state of aggregation. For example, liquid sulfide is stored for no more than 2 weeks, while solid sulfide is stored for several decades. Check the manufacturing date before purchasing.
To carry out the reaction, you will need an empty container where solid sulfide is diluted or where liquid sulfide is poured. Dilute the reagent only with water (it can be cold or hot, there is not much difference). Be careful not to let its fumes enter your respiratory tract.
It is better to carry out the entire procedure outdoors or in a well-ventilated area. As for protecting your hands, it is better to wear protective gloves made of rubber or latex on your hands to prevent aggressive substances from getting on your skin. For added protection, wear regular glasses over your eyes.
If for any reason sulfide gets on the skin, the affected area must be washed thoroughly. running water. The same is done if it gets into the eyes. If the reagent penetrates inside, it is necessary to induce vomiting and immediately consult a doctor.
Depending on the type of substance, it must be prepared in different ways:
- Liquid and gel sulfide are diluted according to the instructions on the label;
- The solid is first crushed to a powdery state, after which it is mixed with water until completely dissolved.
To darken copper, a cold or slightly warm solution is needed. Before throwing the metal into the solution, you need to prepare a solution of water and soda in a ratio of 1:16. Baking soda will neutralize the effect of the aggressive substance and will immediately stop its action.
Copper salt changes color.
Place the copper piece or product in the container and carefully monitor the reaction. Remove the product only using metal tongs. Once the blackening reaches the desired consistency, remove it from the sulfide solution and place it in baking soda to stop the reaction.
If blackening occurs too slowly, then the container can be slightly heated, this will speed it up. To speed things up even more, you can add 5 milliliters of ammonia. It is worth noting that the presence of ammonia gives copper a reddish tint rather than black.
If the copper turns out to be too dark, it can be lightened using a regular detergent powder. Apply a little powder to the hard surface of the washcloth and scrub thoroughly. After which the product is washed in warm water.
Homemade solution
This method produces green or brown copper. To prepare the mixture you will need: ammonia solution, baking soda, water and an empty container. Before you start changing color, the part must be prepared - washed in warm water and wiped dry.
When working with ammonia, it is necessary to observe safety measures: conduct experiments only in a well-ventilated area, wear gloves on your hands and protect your eyes from harmful fumes and splashes.
To obtain green copper, blackening must be carried out with: an empty container into which 0.5 liters is poured. vinegar, 125 ml iodized salt and 375 ml ammonia (pure). Required Ingredients can be purchased at stores and pharmacies. The amount of salt added affects the color saturation. Dip the copper into the prepared mixture for a few seconds and carefully monitor the reaction. Once you are satisfied with the blackening, remove the item and rinse with water.
Copper can also be made brown. For these purposes you will need baking soda, water and a bottle. Soda must be added to the bottle until it stops dissolving. Place the metal object in the container and fill it with the prepared mixture. It is highly recommended not to use sprayers or other methods of applying baking soda solution to copper. This will result in an uneven coloring of the copper item.
The wet object is wrapped in plastic bag and left in this form for 1-8 hours, depending on what contrast you want to get the color.
Thus, you can change the color of copper at home. For this you will need metal container with lid, water, copperware, soda, vinegar and ammonia. Most of the ingredients listed are available at grocery stores and pharmacies. When conducting experiments, do not forget about safety - use glasses and rubber gloves.
Video: Copper Story
