Airplane painting and paint history
Previously varnished on cloth
You might be surprised to hear varnish on the cloth, but it’s about when the Wright brothers flew their own Light Flyer in Kitty Hawk.
The maximum speed of an airplane at that time was about 50 km/h.
Since the wings were made of cloth, they were “dope painted” for the following purposes.
●To prevent the material cotton and hemp from shrinking
●To increase water resistance
●To reduce air resistance caused by fluffing of the cloth
A “dope paint” is a type of varnish that is used to strengthen cloth, wood, and paper.
Unlike ordinary paints, it soaks into the material, makes it stronger, and is light, which was useful for airplanes of the time.
There are nitrified cotton dope and CAB dope, and I think the name nitrocellulose is more familiar to nitrification cotton.
There is still a plane paint called Dope on sale in the United States.
In the old days, it was customary to varnish cars and planes. However, this had the drawback of being flammable.
When it entered World War I in 1914-1918, it changed dramatically.
Initially, planes were primarily reconnaissance planes, but when bombs were dropped, the planes became different.
Equipped with weapons, aircraft made of wood and cloth will be made of metal and will dramatically increase speed.
Evolved in a process similar to a car
Since then, aircraft materials have changed from duralumin and aluminum alloys to resin composites, but their coatings have evolved like automobiles.
The aluminum alloy was coated with nitrocellulose lacquer, alkyd enamel phthalate and acrylonitrile cellulose lacquer.
Epoxy primers are currently coated with urethane or fluorine topcoats.
The coating system for composite materials is extremely complex, changing from the previous four layers to five layers with different structures.
The purpose (also for cars) is protection and a beautiful appearance
Some planes were drawn only with the company’s marks and lines, saying “economical priority is higher than aesthetics!” (Planes are fully painted recently.)
At this time, the unpainted surface had a treatment called “polished skin”.
This is a method of polishing aluminum clad material, metal skin, with an abrasive called a polishing compound and using the oxide film formed on the surface of the aluminum clad material to prevent corrosion of the machine body and maintain its luster.
A time when there was no precedent for transatlantic landing. The Spirit of St. Louis in Lindbergh has five ham sandwiches for landing-free crossings. At the time, the wings and rear of the aircraft were made of cloth, but the metal on the front of the aircraft is said to be this polished skin.
B29 also had polished skin. It is a product of the era when stealth is no longer needed.
Modern airplane painting and paint
Seven requirements for aircraft painting
The conditions for paint applied to aircraft. At least the following conditions must be met.
1) Room temperature curing
2) Absorb/follow the deflection of the aircraft
3) Impact resistance from extremely low temperature to high sound
4) Oil resistance of hydraulic equipment to flame-retardant hydraulic oil
5) Erosion resistance to withstand contact with large air flow
6) Corrosion resistance
7) High level weather resistance
We are checking various tests to see if they meet these requirements.
This high-performance paint seems to be used in wind power propellers.
Aircraft paint standards
For modern aircraft paints, each aircraft manufacturer has its own paint standard, and there are almost as many standards as there are manufacturers.
However, although the standard values are different, there are some parts that are common to all manufacturers. For example, there are the following items:
- Packing state
- Nonvolatile substance
- Weight per gallon
- Grain size
- Mixed viscosity
Besides, it seems to have gloss, tape resistance, low temperature impact resistance, peelability, etc.
The standard of liquid quantity is gallon and the unit of temperature is F, so it is American style.
VOC compatible waves are also here
Recently, eco-friendly top coats and eco-friendly primer coats have also been adopted.
Compliant with VOC, high solid content (low volatility), and excellent weather resistance and durability extend recoating intervals and reduce the amount of release coating film waste. Furthermore, paints that have the same adhesion and rust resistance as conventional primers and a light coating weight but a sufficient solvent content are now available.
Aircraft paint manufactured in the United States has a VOC content limit regulated by California’s regulation R1124, but recently it seems that aircraft in each country often use paint that has passed this regulation.
Timing and construction period
In the conventional type, the repainting cycle is about every 5 years, but for weather resistant paint (fluorine), the guideline is about 10 years. It usually takes about 10 days.
In the case of fighters, the top coat is repeated every few years and repaints in about 10 years.
|Old paint peeling|
|Wash with water|
|Corrosion removal, Sealing|
|Top coat painting etc.|
|Masking paint, Finish|
Pandas and Pokemon are not films but coatings
In recent years, the number of dedicated coating machines has increased.
Many people think that films are stacked like bus advertising, but they are not.
Painting called special paint, that is, they are all painted.
These are a bit expensive for their buzz, but they are appreciated and used not only by second-generation parents and children, but also by grandparents, airplane fans, painted character fans, and more.
Radio wave absorption paint, Stealth fighter
It is a paint that absorbs microwaves of 3-30 GHz and has conductivity, dielectric properties and magnetism.
Although details are not disclosed, these paints are also active in the field.