TECHNOLOGY OF SURFACE TREATMENT OF METALS

Polishing of iron

The polished ironware is immersed for some time in a mixture consisting of 1 part sulfuric acid per 20 elements by the water capacity, then the object is removed, thoroughly rinsed with water and dried in wood sawdust. After drying, it is immediately immersed in nitric acid for one or two seconds, then rinsed again with water, again dried in wood filings and then carefully wiped. In this case, the surface of the object becomes bright, like glass. Only the above method can achieve such perfect polishing.


Finishing of locksmith's products

To give plumbing products a beautiful view, resort to various means depending on the nature of the work. Fine art forgings get a good look, if at the end they are supplied with an intense black color. But for such works, the paint is applied in no way by spreading, but the following operations are carried out: a flame is produced in the furnace, corresponding to the size of the processed object. Fire in no way should not smoke (it is best to consume coke for this). Then the object is greased with an ordinary linseed oil and subjected to the action of a flame, but only for such a time until the oil evaporates and the residue does not burn to the iron. After cooling, firmly rub the object with a cloth slightly impregnated with linseed oil.

The smoother the surface was with iron during processing, the more beautiful the deep black color would look. This color is extremely strong and also perfectly protects from atmospheric influences.

To etch iron elements in black paint, they must be clean, brightly straightened and also polished. Then they are lubricated with liquid oil and sprinkled with wood ash, then they are kept above the hot coals, before the runaway black color does not turn out. After cooling, the objects are washed in water, to which a few drops of sulfuric acid are added, and immediately they are thoroughly wiped off with a coarse, clean rag. Rubbing with oil protects the product from the effects of air. To make the iron particularly soft, it is heated red hot, hastily cooled in soap, heated again until scarlet heat, and, putting it in lime powder, allow to cool slowly. When finished in this way, the iron becomes very viscous and soft.


Cleaning of copper objects

Cleaning of copper objects is as follows: polished copper objects are wiped first with a soft cloth soaked in kerosene, but then cleaned with a woolen cloth with chalk powder or plaster. "Viennese" lime. Highly neglected copper objects give a shine, wiping the object with a cloth moistened with dilute hydrochloric acid. Then clean, as if indicated above, or dissolve 30 liters of oxalic acid in 1 liter of water, add 4 tablespoons of alcohol and 3 tablespoons of turpentine. After that, the liquid is shaken well and bottled for storage. When used, the object to be cleaned is lightly wiped with this liquid, but then wiped with a dry cloth of cloth: copper is quickly cleaned and becomes shiny.


Cleaning of nickel items

Nickel objects that are to be cleaned are first moistened with a mixture of 50 elements of alcohol (or vodka) 2-3 times with 1 element of sulfuric acid; Then they rinse with water plus, flushing with alcohol (or vodka), wipe with a thin linen cloth.

Rust on nickel is removed as follows: lubricate the object with some fat and leave it for a few days, then carefully wipe with ammonia. If rust penetrated deeply, you can take diluted hydrochloric acid instead of ammonia, which, however, leaves no more than a minute on the metal. Then the object is washed with water and polished with chalk also with crocus.


Cleaning of steel items

A simple and good composition for this purpose can serve as a mash of paraffin with oil. Add 1 part of paraffin to the bottle for 20 oil elements, carefully shake until the paraffin is completely dissolved, plus wiping the object to be cleaned, cover it with a brush with this mixture; Then leave for 10-12 hours on the premises, protecting from a speck of dust, after which the object is wiped with a dry woolen rag. If the steel gun or other item requires more thorough cleaning due to significant rust, etc., then use the following composition: prepare a mishmash of 5 elements of turpentine and 25 parts of stearic oil.

This mixture is diluted with alcohol until a viscous liquid is obtained, which also covers the object, and when the alcohol evaporates, the metal surface is wiped with a mixture of 45 parts of animal coal and 25 elements of Kolkotar in powder.


Stamping of iron also became

For stamping steel products (tools, etc.), they usually use caustic acids, which, however, presents many inconveniences, not to mention the fact that the label itself is not quite elegant either. The following method deserves a preference in every respect. Preliminarily, a solution is prepared in 400 g of water of common salt (86 g), copper sulfate (86 g), zinc vitriol (24 g) and ordinary alum (12 g). Then take a piece of guileless soap, damp it with water and rub it that steel object on which they want to make a mark. At the same time, pay attention to the fact that the rubbed area is covered with an even rather not very thick layer of soap; Later, by some sharp object - an awl, a nail or the tip of a knife - the required label is scraped on the soap layer so that the surface of the metal is clearly exposed. Nowadays it only remains to fill the groove obtained in the soap layer with a few drops of the above solution and leave the object in this form for a few minutes. If you then wash off the soap layer with water and wipe the object dry, a beautiful copper color mark will clearly appear on its steel surface.

For etching inscriptions on iron or steel products, mostly dilute nitric acid (15-20%) is used; To apply the acid to the metal object, a rubber stamp is used, but only made of much harder rubber than ordinary ink stamps, which is achieved by a longer process of vulcanization. In order to obtain a distinct etching of the letter, the stamps should be as clear as possible also thin. Instead of a pillow apply a piece of glass on which put a piece of cloth. At the final pour so much acid, so that it is completely impregnated, also tightly pressed stamp. After that, slightly apply a stamp to the metal to be etched, and leave the object for a long time, but then wipe with kerosene, but to prevent the formation of rust - bone oil.


Stamping brass

To apply a strong brass inscription on a smooth brass surface, usually used dye stains are not suitable. For this purpose, so-called "mordants" are needed, which are previously applied either to a glass plate, or directly to a clean pad for stamps. Actually, stamping can be produced with ordinary rubber stamps.

"Mordant" consists of a solution of the chloride salt of a metal; For example, a mishmash of equal parts of copper chloride also of bismuth chloride alienates a good imprint. For this purpose, in a porcelain mortar, both salts are washed together, and diluted with dissolved hydrochloric acid are also stored in a tightly sealed flask. It is possible to erase together I part of the mercury with 2 parts of antimony chloride, adding a little hydrochloric acid to the mixture, and as a result, a liquid suitable for stamping will be obtained.


Translation of drawings for engraving on metal surfaces

We advise you to take a picture, which is desirable to translate, also draw a reverse drawing from it (through the glass). Then cover the metal surface with a weak aqueous solution of gumigut (yellow watercolor paint), put the reverse image on the dried surface and iron it with a smooth object (agate or just a fingernail thumbnail). The contour made with a lead pencil is clearly transferred, and the image can also be engraved with a needle by a grabstihel.


Cleaning of metal parts of machines

We give the best way, practiced now in France, for cleaning metal parts of various kinds of machines. To one liter of kerosene add 10% of paraffin plus, well clogging the vessel, leave it for a day, time from the pores shaking, after which the mixture is ready for use. Then, with the help of the cloth, all the metal elements of the machines to be cleaned are wetted by it. After moistening, leave in this form for the night (and even better for a day) also only the next day they wipe dry with a clean cloth. With this method of cleaning, rust, greasy resin, etc., also leave. And the metal elements of the machines seem to be newly polished. In no other way is it possible to clean them so well, to say nothing of the extreme cheapness of the method itself, which makes it perfectly suitable for this purpose with respect to each kind of machine, the guns, as well as general articles of steel and polished iron.


Protection of iron from rust

This is true if the surface has been previously cleaned well. The following tools are recommended:

1) Coating with substances that absorb water also acids or bind them. So, to prevent rust from steam boilers on ships, a solution of zinc oxide in caustic sodium or solid carbon dioxide zinc oxide is added to the water. In addition, the steam boilers when they are suspended fill with lime milk or soda solution. Better place in well-dried (by means of firebox) potassium chloride boilers in pieces with the size of walnut with the simultaneous termination of air access. In tunnels for the protection of iron from rust, limestone crushed stone is used or the iron parts are covered with limestone milk; In this way, the binding is also made to neutralize a very harmful element giving rust, namely sulfurous acid in the flue gases of locomotives. Nuts in tunnels are covered twice with tar.

2) The coating of the metal is carried out after preliminary etching in acid and after a rapid drying in a hot condition; Objects are immersed in expanded metal or covered with galvanoplastic method in a suitable metal bath.

Zinc is the best fuse (also in seawater), since in a zinc bath on an iron surface, an iron-zinc alloy is always formed. Galvanized iron in trade is often found under the name of galvanized. Better cold electrolytic galvanizing.

Tin protects weakly only as long as the iron is nowhere naked.

Lead also prevents sulfuric acid from hydrochloric acid: lead-coated sheets are used to cover roofs of organic, gas plants, etc.

Copper (galvanic) is also protected by nickel only for a considerable thickness of the layer.

3) Enamelling. The surface of the cast iron mold is also etched out, but then it is covered with a powdery primer (feldspar, quartz, borax, also clay), is fired to flow, and then it is already covered with enamel (silicates with tin oxide) also heated up to the full melting of the enamel.

4) Fats in a solid or liquid state are very convenient for coating cleanly finished surfaces of machines up to assembly. In the open air, fats are washed off by a shower or drained from the action of sunlight. Fat with an admixture of 50-100% of lead white is similarly easy to grow: fatty acids, formed from the decomposition of neutral fats, corrode iron. A mixture of talc with graphite is recommended for the lubrication of wire ropes (once a month). Recently, mineral fats, dissolved in turpentine or in easily volatile products of kerosene distillation, are often used.

5) Portland cement not only protects against rust, but absorbs already formed rust on the surface of iron (Monje). Cement is similarly an excellent tool for large castings of also impressive iron structures. Finely sifted, diluted in water, the cement is applied with a brush to metal clean surfaces. The coating is repeated from 4 to 5 times after the final layer solidifies. For surfaces exposed to water (sluices, bottom of vessels), the smallest cement is mixed with skim milk.

6) Tar, asphalt and resin in anhydrous state serve as a good coating for cast-iron pipes. Resin also pipes preheated.

7) Coating with resin oils. Rubber oil: a solution of rubber in turpentine oil. Antioxidant is a powerless gutta-percha solution in gasoline.

8) Rubber also celluloid allows an excellent coating for nails, screws, buckles, rings, etc., and these elements are not exposed to air, water, acids at that time. This is very proud of electrical insulators. We recommend the coating of ship shafts with solid rubber. Parts of vehicles on long-distance vessels are covered with a solution of celluloid.

9) Coating with oil paints is most common. Flaxseed boiled oil easily lags behind; It is better to take a liquid for the priming of liquid, hastily drying linseed boiled oil mixed with graphite, ocher, iron suri (no more than 20% clay) or better with leaden suricum. Under the water, only a leaden surrey has justified itself. After the priming, the actual painting is done, for which a pure cooked flaxseed oil with lead white (and not with zinc), graphite, zinc dust, and also with chalk additive is taken. To avoid the formation of bubbles, another layer is applied only after the final hardening of the previous layer.


Protecting silver things from tarnishing

It is known that as if silver, as well as silvered things comparatively quickly dim in the air and also acquire an ugly appearance. To eliminate such tarnish, the following remedy is recommended: a liquid solution of the collodium is also prepared by this thin solution also with a thin even layer of silver or silvered objects; Alcohol evaporates quickly and a thin, completely inconspicuous collodion film remains on the metal surface, perfectly protecting silver from tarnishing under the influence of the atmosphere or gases in it. As experiments have shown, made in museums abroad, silver, covered with a thin layer of collodion, continues to retain its paint, the shine is also polished. If necessary, this refined protective layer can easily be removed with hot water.


The simple means of tinning

Take 10 weight elements of common salt, dissolve in 20 parts of nitric acid, after which 10 parts of stannous chloride (tin salt) and 2.5 elements of ammonium chloride (molybdenum) are added to this solution. To the resulting mixture is added another 40 parts by weight hydrochloric acid and then diluted with a small amount of water. The mishmash prepared in this way is completely ready for use. The object to be tilled must be carefully cleaned first, then all parts of it, which should not be covered in any way, are carefully rubbed with fat, after which the object is immersed in the mixture prepared in the above way, in which they leave, until the layer of the half reaches The proper thickness. Then, taking out the object, it remains only to thoroughly wash it, so that it is completely usable. In addition to fixing or updating the half-dishes on the dishes in this way, it is possible to cover small metal objects with rust in order to protect against rust: fish hooks, traps, wires, etc.