Repainting a plane, be it a Boeing 747, private Lear jet or trainer aircraft is both complex and time-consuming. It requires a skilled team and precision at every stage of the process. The steps that you take to prepare the surface, the equipment and coatings that you use and the environmental conditions that you work in are all critical to achieving a finish that will pass inspection.
How often does a plane need repainting?
An aircraft is repainted several times during its lifetime as part of its maintenance schedule. For short-haul aircraft, a repaint is generally necessary every 5-7 years to maintain the craft's performance and safety in the air. For long-haul, it's usually every 7-10 years.
How to paint a plane in 10 steps
Step 1: Initial bodywork inspection
The team assesses the bodywork for visible damage, wear and tear that will need repairing before painting begins.
Step 2: Mask and seal
All ducts are closed and safety-sensitive equipment protected before sealing up the entire craft. Composite parts, such as windows, antennas, wheel fairings and wingtips, are masked with a suitable protection film. Fragile wing components also need heavy-duty protection while the team climb onto them to paint the fuselage above. The mask and seal process can take up to two days to complete for large carrier aircraft.
Step 3: Sand and strip
Aircraft is stripped of its existing coatings. There are two methods for doing this: sanding and stripping with solvents.
Sanding the aircraft
The aircraft's metal surfaces are sanded by hand using an electric orbital sander. The time lapse video below demonstrates the process which can take 3-5 days in reality!
The ultimate sanding system for aerospace
The Mirka range of sanding equipment makes an ideal choice for the aerospace industry. Its specialised disks and extraction system achieve dust-free sanding, helping to maintain a cleaner and safer painting environment.
Stripping the fuselage
Solvents are sprayed onto the aircraft's fuselage to dissolve previous coatings. This process can take up to 24 hours to complete. The time-lapse video below shows chemical stripping in action on an Emirates 777.
Step 4: Wash and decontaminate
The team use high-pressure sprayers to wash the stripper solution, loose paint and other contaminants from the fuselage and wings. This can take anything from 24-36 hours.
Step 5: Second bodywork inspection and repairs
With the aircraft back to bare metal, bodywork technicians perform a second inspection to finalise repair requirements and then make the repairs.
Step 6: Prepare plastic and fibreglass components
All exposed fibreglass and plastic components are sanded smooth, again using an orbital sander, such as Mirka's dust-free sanding system.
Step 7: Prepare the bare metal
Most aircraft bodies are made from aluminium - a metal which requires etch and Alodine treatments to ensure proper paint adhesion and to prevent corrosion. A brightener and etch primer is first scrubbed into the aluminium surface by hand using rough-textured non-metallic pads. An Alodine chromate conversion coating is hen applied to change the aluminium surface from chemically active to relatively then applied to change the aluminium surface from chemically active to relatively inert.
After treatment, the aircraft is ready for another thorough rinse and blow out with dry compressed air.
Step 8: Apply the paint
The aircraft is painted in three layers of specialised technical coatings: a primer bonding coat, an anti-corrosion basecoat and the livery topcoat. The production team use a high-volume, low-pressure spray system to apply each coat in ultra-fine and even layers. Coating thickness is crucial as excessive paint build up will reduce the craft's operating efficiency.
The aircraft is left to dry and cure completely before being unmasked.
Step 9: Replace the technical markings
All technical markings are replaced and inspected in line with Civil Aviation Authority requirements for that aircraft. This is done in a very specific way, following detailed technical drawings and instructions to the letter.
Step 10: Apply the final clear coat
After fixing any blemishes and chips under the topcoat that may be vulnerable to corrosion, technicians spray the final clear coat in a fine and even layer. It can take up to 16 hours to apply; then it's a 48-hour wait for the finish to dry before you fly!
Get support from the aerospace coatings experts
The Ultrimax team are specialists in the aerospace sector. Our Total Paint Shop Support Team can help you with everything from buying equipment and sundries to troubleshooting paint finish issues - contact us for more information.