Without paint can be painted many metal surface, if you cover them (chemically or electrochemically) with a thin layer of colored oxides or salts, are strongly linked with the surface. The last condition to perform not so easy. For example, iron in moist air quickly (and without our help) is covered with reddish-brown patina oxidation products, simply put - rust, but this method of painting is no good, because rust barely kept and dirty to the touch.
Here we present a few recipes for painting of non-ferrous metals. Only some of them are suitable for home experiment, others require chemical reagents, which you cannot buy in a pharmacy or in the shop. However, I hope you are already enrolled in chemical circle.
Copper and brass quickly fade in the air. But they will retain the Shine, if you paint them by chemical means. Preparation details will take some time, because the surface must be completely clean, with no traces of dirt and grease. Polished item wipe with a cloth soaked in gasoline, and then wet chalk or tooth powder. Rinse the item under running water, hang it on the harsh thread or fishing line and do not touch more hands, so as not to leave grease (even if the skin to be completely dry, still there is a little fat). Immerse the item in a dilute solution of nitric acid (no more than 5-10 ml per 100 ml of water) and rinse again, better with hot water. The preparation is completed.
The future depends on what color you decide to paint the copper. If black, then hold the item for five minutes in a solution in which 100 ml of water is necessary 0.9 g sodium hydroxide and 0.3 g of ammonium persulfate (NH4)2SO4 (it is used in photography). The solution temperature of 90-100°C.
In a solution of potassium chloride, Nickel sulfate with NISO4 and copper sulfate CuSO4 (4,5 respectively, 2 and 10.5 g per 100 ml of water) at the same temperature copper and brass will get a nice chocolate color. Brass will be French after a short incubation in a mixture consisting of 3 g of lead acetate (you can use a lead lotion), 6 g of sodium thiosulphate (hyposulphite), 5 g of acetic acid and 100 ml of water. The temperature of the solution to about 80°C.
Copper can be POSELENIE. To do this, it needs to be dipped in such a solution: 100 ml of water 20 g of copper nitrate cu(NO3)2, 30 g of liquid ammonia and 40 g of ammonium chloride (Sal ammoniac) and sodium acetate; the solution of the latter substances are easy to obtain from soda and vinegar. With nitrate of copper, please, gently, avoiding contact with the face and especially in the mouth.
With the exception of experience with blacking, we never specified reaction time. Pick it up yourself on experience, taking into account that the longer the treatment time, the more intense the color.
The following metal which lends itself to chemical colouring, is zinc. It is used infrequently, but with galvanized items, buckets, basins, troughs - are all familiar with. The object of the experiment can be any old junk galvanized the subject. Rinse the surface with a solution of soda or wipe with a rag soaked in gasoline, hot wash with soap and water and rinse several times. Galvanized surface apply a mixture of substances, which will come with zinc in the reaction; giving a colored compound. Here are the recipes for paints.
Black: 2 parts of nitrate of copper, 3 parts of copper oxide, 8 parts of hydrochloric acid and 64 parts of water; after the appearance of the paint surface should be washed with water and dried.
Green: 10 parts of copper sulfate and tartaric acid, 12 parts of water and 24 parts of sodium hydroxide solution in water (1:15); as soon as the painting, now rinse the surface with water, otherwise it will be brown tint.
Blue: 100 ml of water, 6 g of any of Nickel salt and the same amount of ammonium chloride,
Gold: a solution of 1 part tartaric acid, 2 parts soda to 1 part water mixed with pure clay; surface to RUB the mixture, and when it dries, rinse with water.
Brown: a mixture of 1 part Jari-Copperhead and 5 parts acetic acid; surface to RUB the mixture, rinse with water and dry.
Copper: as zinc is more active than copper, so it is enough to moisten it with a solution of a copper salt, e.g. copper sulphate.
Incidentally, these paints can be drawn on zinc surface picture.
From zinc will move on to the aluminum. Paint it a bit more difficult: and operations anymore, and cannot do without electric current. Oxide and aluminium salts plain, therefore, need a different way of colouring. He is known for, it anodizing. Its essence is that through the aluminium component is immersed in the electrolyte, pass current; when it is formed on the surface of the oxide film of a thickness of less than 0.1 mm as aluminum details in the galvanic bath serve as the anode, a process called anodizing. Oxide film is permeated microscopic branched pores, which are resistant dyes. Can be painted anodized surface and organic dyes, including natural, but better still inorganic substances. Typically, the item is treated alternately in the two dye solutions, and brightly colored reaction products remain in the pores.
Polished aluminium detail, degrease it with petrol or acetone, rinse in hot water and hang on the wire. Immerse the item in two or three minutes in 5%sodium hydroxide solution, again rinse and soak in a weak solution of nitric acid (20-30 ml of acid per 100 ml of water). Of course, details to touch anymore, and if suspension to work uncomfortable, help yourself with tweezers.
Again rinse the parts in hot and in cold water and hang on the wire in the glass. You can put on the edges of the glass wand or pencil and wrap wire around it, picking up such a height that the item was a few inches above the bottom. Connect the item with the positive pole of the current source. Cathodes - steel plates - hang the same way. The power source may be batteries, but they are very quick "sit"; a battery or transformer with rectifier preferred.
In a glass item pour the sulfuric acid solution (20 ml acid per 100 ml of water; be careful!). Turn on the key chain or a switch and a rheostat to regulate the current. For its measurement need milliammeter, but good and tester, which is a lot of hams. Short circuit and set the current based 20-25 mA 1 cm2 surface. The item will immediately be covered with gas bubbles is allocated oxygen, which oxidizes the aluminum. At room temperature the process lasts about an hour.
Rinse anodized detail in the flowing water and start painting. Immerse the item in turn in two dye solution, soaking in every 5-10 min and washing every once in flowing water. Painted details again rinse and dry.
Here is the coloring compositions of the solutions and their possible concentration (in grams per 100 ml of water):
- blue or blue - ferrocyanide of potassium (1-5) and iron chloride ( III ) (1-10);
- brown - ferrocyanide of potassium (1-5) and copper sulphate (1 - 10);
- black-cobalt acetate (5-10) and potassium permanganate (1,5-2,5);
- yellow bichromate of potassium (5 - 10) and lead acetate (10-20);
- Golden yellow - sodium hyposulphite (1-5) and potassium permanganate (1-5);
- white-lead acetate (1-5) and sodium sulfate (1-5);
- orange-bichromate of potash (0.5 to 1) and silver nitrate (5-10).