The process of burnishing gun barrels is aimed primarily at protecting metal from corrosion. In addition, various chemical and electrochemical methods of coloring the trunks, giving them different colors and shades, make the gun itself less noticeable for game.
Preparation of hunting gun trunks for burnishing with acid oxidation, grinding, polishing, salting and degreasing.
There are many recipes for painting metal parts of hunting rifles. Using various chemical compositions and methods of coloring, you can get a wide variety of colors. But for all, without exception, burnishing methods, the common thing is that immediately before painting, the trunks and other metal parts of the guns must be thoroughly cleaned from rust and stains to full whiteness. And only after that produce burnishing.
, which is often called differently – rusty varnish.
Method of burnishing with acid oxidation, preparation of rusty varnish composition.
Rusty varnish refers to compounds that cause increased rusting of the steel surface with the formation of magnetic iron oxide. They are acidic solutions of iron salts, sometimes containing salts of mercury and some other heavy metals.
Method of preparation of the composition “rust varnish” for burnishing with acid oxidation.
To prepare the composition you will need:
Technical hydrochloric acid: 50 ml.
Concentrated nitric acid: 54 ml.
Chips of cast iron or carbon steel: 30 g.
Metal scale: 20-30 g.
Distilled or drinking water: 1 liter.
The process of preparing the composition can only be carried out outdoors. Make sure that the wind blows from you, as the reaction is accompanied by gas evolution. Pour 50 ml of hydrochloric acid into a glass flask with a capacity of 1.2-1.5 liters, add one third of cast-iron shavings and scale to it, then carefully add one third of nitric acid.
After a while, the mixture turns green a little and starts to boil, heating up and releasing brown gas. Wait until the reaction calms down a bit, and add as much scale chips and another third of nitric acid. The boiling will resume for a few more minutes, then subside, after which you can add the remaining chips and acid.
As a result, you should get a creamy mass of red color, which must be allowed to infuse for at least 24 hours. Wrap the neck of the flask with plastic wrap and securely fasten the latter. This must be done, because the reaction in the flask will continue for several hours, while emitting a small amount of gas.
After a day, proceed to the second stage. To the creamy mass obtained the day before, add one liter of prepared pure water to the flask. Everything, the composition for oxidation by the method of “rusty varnish” is ready. The contents of the flask must be shaken and poured into a wide-necked container, with which you will be comfortable working.
Excess chips and scale that may not react with acid may remain at the bottom of the flask. The prepared composition does not need special storage conditions, with the exception of normal safety measures, and will serve you for many years. Ready “rust varnish” is safe for hands and lungs.
Preparation of a metal surface for acid oxidation, grinding, polishing, peeling or matting.
Before oxidation, the metal surface must be carefully sanded and polished. To obtain the most smooth and even surface of the workpiece, grinding is carried out in several stages. First, grinding is carried out with sandpaper, from relatively rough to “null”, and ends with a thin abrasive treatment. On this metal preparation can be considered complete.
If you want to achieve a better result, you can perform another, additional operation called salting or matting. This operation is applied before the oxidation of elite weapons..
Exfoliation is usually carried out on round hair brushes, using pastes consisting of a fine abrasive, evenly mixed in a mixture of technical fat and stearin. The cutting properties of emery grains lubricated with fat are significantly weakened, and the organic acids present in the fat contribute to the removal of the oxide film from the treated metal.
As a result of salting, the surface of the parts becomes much smoother and smoother, which contributes to better polishing with cloth circles lubricated with polishing pastes. To obtain a high quality finish, it is recommended to apply salting immediately before polishing. It should be noted here that the higher the quality of grinding and polishing, the better the surface of the oxidized metal resists wear and the higher its anticorrosion properties.
Degreasing a metal surface before acid oxidation.
The purpose of this operation is to remove fats, various contaminants and mineral oil residues from the metal surface, since the oxide film is formed only on a clean metal surface. For degreasing, a solution of the following composition is used (based on 1 liter of water):
Caustic soda (caustic soda): 10-15 g
Trisodium phosphate: 50–70 g.
Soda ash: 30-40 g.
Liquid glass – 3-5 g.
If the oxidized gun barrels are soldered with tin solder, then it is better to apply the following composition:
Soda ash: 100-150 g.
Liquid glass: 20-30 g.
With both methods of degreasing, the temperature of the solution should reach 90-100 degrees. The exposure time of parts in solution is about 15-30 minutes. After the parts are in the degreasing solution for the specified time, raise the trunks. The liquid should uniformly cover the surface of the metal, not collecting in drops. It can be considered that complete degreasing is completed..
Fat-free parts must be thoroughly rinsed in water. Now you can start burnishing and start applying to the surface of “rusty varnish”. Try to minimize the time between these operations so that no oxide film forms on the metal surface..
Based on materials from the book Fishing tackle and do-it-yourself hunting equipment. Manufacture and repair.