Blackening copper at home video. Homemade selective coatings. Methods using chemical reagents. Do-it-yourself patination (blackening, aging) of copper, brass and bronze Blackening copper at home
Scunc 10-02-2015 14:14
Health and success to all!
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 sulfur 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.
Visitor 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 is an excellent blackening agent.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 it. But you must definitely take Potash (POTASSIUM carbonate), specifically, with baking soda (SODIUM carbonate) the effect is not the same, it is less stable, and the coating is one after another. 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 it slightly with water - and go, cheap and cheerful.
niks78 10-02-2015 16:39
and when I stained the oak with ammonia, I laid the copper busbar 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 large number 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 it. But you must definitely take Potash (POTASSIUM carbonate), specifically, with baking soda (SODIUM carbonate) the effect is not the same, it is less stable, and the coating is one after another. 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! It's 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! 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 various 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 in divorce. 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. IN various recommendations It is proposed to fuse 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 for that much longer.
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. 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 in 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 the 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 for that much longer.
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 in 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.
Let me make a reservation right away that I am not a chemist, and all my knowledge is only what I have left over from school. Therefore, the recipe was not fully followed and some deviations were made.
Bluish-black color.
Treatment lasts 25-30 minutes. at a temperature of 15-30°C.
Preparation of copper carbonate.
In this case, when recipes mention copper carbonate, in fact, they are usually talking about basic copper carbonate. To obtain it, you can use copper sulfate, acetate or nitrate. A solution of potassium or sodium carbonate (potash, soda) is added to an aqueous solution of one of these salts. The green-blue precipitate that falls consists of basic copper carbonate of variable composition, nCuCO 3 x mCu(OH) 2, where n and m can vary within some limits, which for us, in this case, is not very important. The precipitate is filtered off, washed with water and can be used.
The process itself.
To blacken brass using this method you will need:
- copper sulfate;
- baking soda;
- ammonia;
- two glass jars, preferably the same volume;
- filter paper or something similar;
- stirring stick.
The vitriol was purchased at the nearest hardware store in the department that sells all sorts of pesticides to combat garden pests.
Soda - in the nearest grocery store, where there is simply plenty of it.
Ammonia - at the nearest pharmacy. But only 10%. As they explained to me, 25% is not for sale due to its danger.
First we prepare copper carbonate. For this we need copper sulfate and ordinary soda. |
|
 | Dissolve the vitriol in warm water. The solution needs to be saturated, i.e. add vitriol until it still dissolves. The solution must be made so that it occupies only half the container. |
 | Then slowly, a little at a time, add soda to the saturated vitriol. It is precisely because the solution begins to bubble like soda that I recommend making vitriol in only half the container. |
 | Stir. Over time, the seething subsides. I poured baking soda until the bubbling stopped. After a while you will see that you have obtained a finely dispersed suspension of pleasant turquoise color. On the surface you can see that the fry are still seething there. |
 | Now the resulting suspension must be filtered. There was nothing worthwhile at hand except napkins. The recipe says to dry it. But I didn't do this. |
 | Now we need a 25% ammonia solution. As I already wrote, only 10% is available in the pharmacy. This is what we will use. |
 | Little by little add turquoise porridge to ammonia. The solution turns blue. |
 | We also need a saturated solution. Therefore, we add, without sparing, copper carbonate. You will end up with a blue-black liquid. That's what we need. |
The solution is ready, all that remains is to put the necessary parts in there. Blackening time, according to the recipe, is 25-30 minutes.
If the part is kept in the solution, copper carbonate will settle on it in the form of turquoise crystals, which, in principle, can then be easily scraped off with a fingernail without damaging the blackening;
If you have difficulty removing blue sediment from a part, I recommend simply heating it in the flame of a candle or lighter. The sediment will immediately fall off on its own.
Patination of copper, as well as other methods of its decorative processing(including at home) make it possible to make products made from this metal more attractive and give them a touch of noble antiquity. Items made not only of copper, but also of its alloys such as can be subjected to this treatment.
Patination and oxidation
The surface of many metals (and copper is one of them), when interacting with the surrounding air and various chemicals, begins to become covered with a thin layer of oxides and oxides. Such a process which also results in color change metal surface, called oxidation. For the most part, the process of metal oxidation occurs naturally, but people have learned to cause it artificially, in industrial or home conditions, which is done to give the product an aged appearance.
Oxidation should not be confused with patination, a process whose essence lies in the fact that on the surface of the metal, when interacting with various chemical elements a thin layer of sulfur or chloride compounds is formed. Patination, which, like oxidation, is accompanied by a change, can also be performed artificially using special compounds.
Copper aging occurs naturally over time or immediately when the surface is treated with any preparations.
If under natural conditions the process of oxidation and patina coating of copper or bronze can take years, then when using special solutions, patination occurs in a very short period of time. The surface of a product placed in such a solution literally changes its color before our eyes, acquiring a touch of noble antiquity. Using various chemical compositions, you can perform such procedures as blackening of copper, patination of objects made of copper and bronze, and blackening of brass in production and even at home.
Preparation for processing
Having decided to perform patination or oxidation, you should not only carefully study the question of how to age brass, bronze or blacken copper, but also provide the necessary safety measures. Supermajority chemical compositions, which are used to carry out such procedures, are very toxic and emit fumes that pose a significant danger to human health. Therefore, to store such substances both in industrial and at home conditions, you should use vessels with well-ground stoppers, which will prevent toxic vapors from entering the surrounding air.
The procedure itself, carried out to change the color of the surface of a product under the influence of chemicals, should be performed in a special cabinet to which the exhaust ventilation. It should be borne in mind that the doors of such a cabinet should be slightly open during the process of oxidation or patination, which will ensure effective extraction of harmful vapors from its interior.
Products made of copper, brass and bronze before patination should be thoroughly cleaned, degreased and washed in warm water. After the patination or oxidation procedure itself, the treated objects are also washed and placed in sawdust to dry. Using sawdust is a more gentle drying method, since performing such a procedure with a fabric material can damage the thin film of the formed patina, which has not yet been fixed with varnish. In addition, using fabric after patination it is almost impossible to qualitatively remove moisture from the recesses on relief surfaces, and sawdust can easily be pulled out.
Changes in color of copper and its alloys from gray to black
Grey, dark gray or black and its alloys makes appearance products more attractive and presentable. To obtain these colors, the degree of saturation of which can be adjusted, you need the “liver of sulfur” composition that has been used for decades. It got its name due to the fact that during the cooking process it must sinter, that is, turn into a caked mass.
To make such a composition for patination at home, you must follow these steps:
- one part of powdered sulfur is mixed with two parts of potash;
- the resulting mixture is placed in a tin can, which must then be put on fire;
- After waiting for the powder to melt and begin to sinter, it is necessary to maintain this process for 15 minutes.
During the sintering process of the powder, a blue-green flame may flare up on its surface, which does not need to be knocked down, as it will not worsen quality characteristics sulfur liver. After sintering is completed and completely cooled, the resulting mass should be crushed to a powder state. This powder, if placed in glass jar With a tight-fitting lid, it can be stored for a long time.
In order to patina various metal alloys using liver sulfur, several basic methods are used.Method No. 1
This method involves the use of an aqueous solution of liver sulfur. It can be used to change the color of products made from the following materials:
- copper;
- sterling silver;
- bronze and brass.
The colors that can be used to paint the surfaces of products using this method also vary:
- copper and silver - purple, blue (very difficult to obtain), gray, brown-gray, black;
- brass and bronze – soft golden.
If you did not know before how to age copper and form a durable patina film on the surface of this metal, distinguished by a rich black color, use this method. To implement it, a copper product is placed in a solution consisting of a liter of water and 1–20 grams of liver sulfur powder.
To color copper light gray, the solution is prepared according to a different recipe: 2-3 grams of sodium chloride and liver sulfur are dissolved in 1 liter of water. A copper product is placed in the resulting solution, the color change of which should be carefully monitored. After the color of the metal acquires the desired tone, the object to be patinated must be washed with water and dried in sawdust.
To patina copper, you can also use a solution prepared according to the following recipe: ammonia is added to a saturated aqueous solution of copper sulfate and this is done until the liquid becomes transparent and bright blue. The cleaned and degreased product to be processed is placed in such a solution for several minutes, after which it is removed and subjected to slight heating. After such manipulations, the copper should acquire a rich black color.
Method No. 3To use this method, which also allows you to qualitatively blacken copper even at home, the object being processed must be cleaned using a fine sandpaper. Do not touch the cleaned surface with your hands to prevent grease stains from forming on it. After preliminary preparation for patination, the object is treated with a solution of platinum chloride or completely immersed in it. A small amount of hydrochloric acid can be added to such a solution, if it does not cause an acidic reaction.
Method No. 4A durable oxide film distinguished by a rich black color can be formed on the surface of a copper product by immersing it in a composition prepared from nitric acid And metal copper. To make the color change of the copper part more intense, this solution can be further heated.
Getting a patina of other colors
To form an oxide film of a different color on copper, you can even use one of the following methods at home.
Red-brownTo obtain a red-brown oxide film, the copper product is placed for several minutes in a composition prepared from one part copper sulfate, one part zinc chloride and two parts water.
To obtain such a patina, a copper object must be placed in a solution consisting of one liter of water and 20 grams of ammonium sulfide. By changing the heating temperature of the processed product before patination, you can adjust the intensity of coloring.
Light brownTo give the surface of a copper product a light brown color, it is necessary to treat it with a mixture of sodium chromium (124 g/liter), nitric (15.5 g/liter) and hydrochloric (4.65 g/liter) acids, 18% ammonium sulfide ( 3–5 g/liter). This solution is applied with a brush and left for four to five hours.
Copper is a metal that has low activity and for this reason is often used in decorative purposes. Made from copper jewelry, interior items, 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 available 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 on fire in 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 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 solution of copper nitrate in low concentration 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.
Can be obtained amazing beauty 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 when 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 prevent damage to the top layer, 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 lay down evenly, then the old layer must be cleaned to a metallic shine.
