Aircraft can be seen painted in a variety of colors, many with logos and unique and attractive designs. However, the painting on an aircraft is more than just the aesthetics we see on the outside.
Aircraft painting is also a protective feature for the aircraft. The topcoat finishing that is applied is used to protect all of the exposed aircraft surfaces from corrosion and deterioration. Aircraft that are properly painted and have the perfect body finishing are easier to maintain and clean. Those exposed surfaces are more resistant to dirt and corrosion as oils and other forms of dirt do not easily adhere to the surface of the aircraft.
Painting an airplane is not as easy as it sounds. Painting incorrectly can alter the weight of the aircraft and can affect the performance of the aircraft if not done properly. Painting, finishing, and coating of an aircraft also involves the use of various chemicals that can be harmful to the user. To be safe while engaging in aircraft painting, the painters need to use a respirator, wear protective clothing and safety glasses and so on.
Materials and Equipment Used in Aircraft Painting
The word paint’ in aviation refers to the variety of enamels, primers, lacquers and other types of finishing materials that are employed for the painting of an aircraft. They all have a different and unique usage which serves to protect the surface of the aircraft and provides the aircraft with the desired style and appearance.
There are three main components of aircraft painting; pigment for color, resin used as a coating material, and solvents for a reduction of the mixture to a viscosity that is appreciable.
The equipment used for aircraft finishing all have unique principles that when used deliver the desired result to the body of the aircraft. Finishing equipment used for aircraft painting includes paint booths, air supplies, air compressors, coating containers, air filters, spray guns, fresh air bathing systems, and mixing equipment.
Aircraft Painting Process
Stripping is the first step in painting an aircraft where the existing finish is removed to expose the bare metal of the aircraft. This step can be done by implementing techniques such as dry-ice blasting and chemical stripping. Although dry-ice blasting has gained huge success recently, chemical stripping is always considered as the most reliable technique. However, the chemicals in the stripper are very harmful. Because of its harmful effects, disposal pd the chemical after the stripping is very important. Even for a small aircraft, a large amount of stripper is needed and a proper place is required to dump this hazardous waste.
The inspection of the aircraft is one of the most important steps in this process. After removing the existing finish, a thorough inspection is done by licensed mechanics. Loose rivets, cracks and other damages that generally hid under the old paint will be exposed after stripping. These defects are identified and repaired before applying the new finish.
Applying the New Finish
This is the final step in the aircraft painting which is done by implementing a two-step process – applying the primer and then a topcoat. Generally, zinc-chromate is considered as the standard primer and it is sprayed with the help of a spray gun. An air compressor is used as a constant air supply as the appropriate spray pressure is very important. Multiple coats of the primer are applied.
The proper amounts of color pigment are purchased before the actual painting begins. Generally, two types of paints are used in the topcoat process- Epoxy, or Enamel. Epoxy is basically a polyurethane paint which adheres very well to the surface of the aircraft and it does not oxidize, fade or break down easily. Enamel is less expensive than Epoxy and it does not produce harmful gasses while spraying it on the surface of the plane, as Epoxy does. Therefore, it is very environment-friendly. In order to protect the final finish, quality masking materials are used. An aircraft consists of ports that allow the outside air to enter into the instrument system. The painters must be careful while painting in these areas as they are not allowed to cover these ports.
Common Challenges with Aircraft Painting
In most cases, the painting process is a routine procedure that is performed flawlessly. However, there are certain challenges that can be encountered. Some of those challenges are not properly stripping the aircraft, using the wrong primer, topcoat and primer incompatibility, incorrect mixing of the topcoat pigments and materials and spray equipment contamination.