Polishing aluminum by one's own hands: ways, means, devices

Aluminum is a fairly soft metal. Any product from it eventually loses its original appearance, on the surface appear scuffs, oxides, the product tarnishes. If you want to give the old thing a new look, then aluminum should be polished. To do this, you can use one of the following methods:

• Electropolishing;
• Chemical polishing;
• Decorative etching.

Methods of polishing aluminum: chemical method

This technology is eco-friendly, simple and fairly fast. It can be realized with acid-resistant steel, which will form the basis of a polishing bath. If the scope of work is relatively small, porcelain crucibles can be used. A solution of acids is poured into the container:

• Sulfuric;
• Nitrogen;
• Orthophosphoric.

Products fall into a hot solution, the temperature of which should vary from 90 to 120 ° C, the final value will depend on the grade of aluminum. Exposure to the composition of aluminum is necessary for 30 seconds or minutes, repeat the action should be about 6 times. In the intervals, the parts are washed, and they must be constantly shaken.

Aluminum chemical polishing will be more qualitative if using a rotating drum at a certain speed. After the completion of such manipulations, a copper contact film remains on the surface. It should be removed by rinsing the products under running water with a low temperature. You need to do this in the trap. At the next stage, the products are treated with 30% nitric acid.

Additional recommendations for works

Polishing of aluminum can be carried out with the help of solutions of alkalis:

• Trisodium phosphate;
• Sodium nitrate;
• Caustic soda;
• Sodium nitrate.

Their temperature should be higher than the acid method, the limit is 120-140 ° C. To withstand the products need about 5-20 seconds. When such a technique is used, the aluminum loss will be approximately 8 μm from the total layer thickness.

Using Electropolishing

Polishing of aluminum can be carried out in another way. In this case, it is possible to obtain a sparkling and smooth surface, and cleaning is characterized by high quality. Electrolytes for such work in most cases have sulfuric and orthophosphoric acid, the remaining components will depend on the material.

Electrolytes allow achieving gloss after the completion of work. For the process, the temperature should be lower than in the above case, the temperature limit will be from 60 to 90 ° C.

Polishing should be carried out for 5 minutes, whereas the current density can be 10-50 A / dm². The polishing process involves the use of lead cathodes, but there are other alloys that involve the use of stainless steel. Polishing requires the use of duralumin suspensions, as well as electrolytic baths with polyethylene, lead or fluoroplastic. It is necessary to prepare alkaline electrolytes, they will cost less.

The process parameters will be affected by the composition of the electrolyte, the temperature limit can vary from 40 to 95 ° C, with regard to soaking, it lasts from 3 to 6 minutes, while the current density at the anode is a limit of 3-20 A / dm². When choosing cathodes, one should prefer nickel-plated.

Features of decorative etching

Polishing of aluminum can be carried out in a decorative way. This technique acts as a subspecies of electropolishing. Alloys of aluminum are etched by anodes according to the regime in the phosphoric chromium electrolyte. On the surface of the products a crystalline pattern is formed, which has the appearance of rosettes or frost. All the details are hung on the anodic bar, and then you can start processing. The manipulations should be performed at a voltage of 25-30 V. By the end, the voltage rises to 35-40 V, the anode current density will be equal to the limit of 8-12 A / dm², while the temperature will vary from 50 to 80 ° C.

After about 20 minutes, a picture will appear. If the voltage starts to rise arbitrarily, then the process can be considered complete. After the end of manipulation, the products are washed, well dried, anodic oxidation is carried out above them. Aluminum is then painted with organic paint.

The mirror shine of aluminum can also be obtained by another method of anodic etching, which is called spark. For this, the products before and after the process are subjected to heat treatment according to a special scheme. You can use the anode etching "snowball", which allows you to create a matte-sparkling surface.

What is the best way to use at home?

The polishing paste is one of the most commonly used at home polishing agents for aluminum. This is due to the fact that chemical compounds are toxic, they are dangerous to human health. For polishing, you can apply:

• Sandpaper;
• Hard brushes;
• Varnish;
• Rags;
• Cleaning agents by type of alcohol.

When choosing a sandpaper, it is important not to overdo it with granularity, because otherwise you will have to remove scratches. To improve durability and gloss, it is better to use lacquer.

Features of electrochemical polishing

Electrochemical polishing of aluminum provides for the implementation of works by the method of parallel chemical and electrical influences. By the technology of this method, the part acts as an anode electrode, a positive current source is connected to it. The billet with the current supplied to it must be immersed in a tank, which is filled with electrolyte. Copper cathodes act as the second electrode.

Using a polishing machine

The machine for polishing is a very convenient means for giving the aluminum an original shine. To do this, you can use a polishing wheel per 1000, which is wetted with water. Use a sponge or a cloth to apply water to the area being treated. Next, the polishing machine is turned on for 1400 revolutions per minute. At a similar speed, the spray will scatter around 1 m around.

The surface of aluminum will become warm, the liquid will evaporate. You should be prepared for the fact that the circle will be clogged with aluminum "porridge". Therefore, every minute the machine should be stopped to rinse the abrasive circle with a wet sponge under the stream of water. To do this, some craftsmen use the usual spray.

"Kashu" should be removed from the details. Mirror shine will be obtained if you additionally use also felt. This stage is one of the most important. It is from him that 80% of the final result will depend. Felt should protrude 10 mm for the base, the circle should be moistened, watering it with a spray bottle. The part is wetted with a damp sponge. The polishing paste is used coarse, it should be applied to the part, not the circle.

Conclusion

Aluminum polishing with their own hands can be carried out by various means, however one of the most effective is paste. It does not contain ammonia additives and is able to gently clean the part from roughness and scratches. With the help of this composition, you can achieve an initial shine. The protective layer will exclude the occurrence of oxidation for a long period.