The use of inserts for painting fighter aircraft in the military has a long-established record of success. It achieves all of the main objectives of a paint booth: protecting against fire, containing volatile organic compounds (VOCs) and providing the proper environment for the painter.
Inserts are used in civil and military facilities. The U.S. Air Force has more than 25 inserts, and the painters who paint in them know what paint finish quality means. Wherever inserts are used, painters have improved control over the painting environment they need to do a professional job and paint rework decreases.
Inserts have been used for fighter jets, such as F-22s, F-35s, F-16s, F-15s, A-10s and UAVs. They have also been used for larger planes, such as the C-17, C-130 and C-141, and many luxury planes, such as the B-707. When compared with a paint barn, they feature clean, smooth and easily cleanable interior walls and surfaces, excellent lighting, controllable and laminar airflows, and reduced paint rework.
Paint Booth Inserts
A paint booth insert is a self-contained enclosure for containing the process operations of painting. The process considerations are safety, health and quality.
- Safety: Fire is an ever-present adversary and must be a prime consideration for the designer. The guidelines for design of paint booths are contained in the many codes and standards that apply to the industry. The remedy is good filtration, control of hazardous materials and monitoring of volatile organic compounds (VOCs) and Lower Explosion or Flammable Limit (LEL) levels.
- Health: The effects of VOCs and heavy metals on personnel are well known. The protection of the environment is a serious consideration for the paint booth designer. The safeguarding of the health of the employee from the effects of aerospace coatings is very important. Coatings containing metals, such as chromates, must be dealt with carefully. Some toxic compounds are also frequently used, especially in epoxy coatings, such as CARC and RAM materials.
- Quality: The overall quality of a paint job is dependent on several factors. Airflow is very important, as is the quality of the process air introduced into the booth. Dirty or contaminated intake air will affect the quality of the paint job and increase the need for rework. For a large aircraft, rework can amount to several days of extra labor to repair defects in the coating. Defects can be visual and unsightly, but most importantly, defects can be the origin site of new corrosion. In the case of performance coatings, defects can be detrimental to low observability (aka stealth), thereby requiring expensive rework to fix.
Inserts and paint booths provide good airflow control and excellent lighting. They also provide a better energy management bargain because airflow is reduced to the absolute minimum required to satisfy the demands of safety, health and quality. The cost of air consumption is very high, especially in intemperate climates where replacement air must be heated or cooled. Reduction of airflow and recirculation are key energy management design tools.
Lighting is a critical element in any paint booth, but in an aircraft paint booth, different problems arise than in an automotive booth. The underside of an aircraft amounts to exactly half of the plane’s paintable surface area, making it a difficult design problem to accommodate. In a paint booth insert, the geometry of the insert helps get lights closer to the surface and directed to fully illuminate the aircraft.
Paint booth inserts are completely standalone facilities that require little or no structural assistance from the enveloping structure. This feature makes it extremely easy to erect a paint booth insert inside an existing hangar facility. Thus we say the paint booth is “inserted” into the hangar.
The use of paint booth inserts is cost-effective.
- By reducing the overall airflow in a paint booth, the size of the air-moving machinery is reduced
- Horsepower is reduced and consequential electrical installation costs are saved
- Ductwork and duct supports are reduced in size and cost
- Accessibility to equipment by use of platforms and storage areas for consumables (such as filters) are reduced in cost due to the reduced quantity required
- Lights are located as close as possible to the aircraft, reducing the quantity of lights required
- Structural demands are minimized due to the standalone concept, greatly reducing steel costs and booth erection costs
- Paint quality is improved due to filtered intake air being moved at a controlled, uniform velocity across the aircraft