The actual repainting involves an 12-step process, according to Leading Edge: mask aircraft composite areas; apply chemical stripper to aluminum surfaces; sand composite surfaces to be painted; alkaline wash aircraft; apply prekote; water break; apply paint primer; apply top coat; apply N numbers, fleet numbers, logos, name and stripes; apply required placards according to the maintenance manual; manicure and touch up aircraft; present to customer.
The length of the process depends on aircraft size. At Dean Baldwin , a 737 usually takes from 6-7 days, a 767 11 days and a 777 13-14 days. At Leading Edge , a 737 takes 8-10 days, a 767 11 days and a 777 12 days.
A base coat-clear coat system has helped speed work. The base coat of color dries quickly, rather than in 12-24 hr. Painters then quickly add a clear coat to give colors a final gloss. Patterson says the mica coat is unique, the base-coat/clear-coat system can be temperamental and it took a while to work out exactly the right size for the mica flakes. But once it had been found, everything went smoothly and the livery sparkles much like the former polished aluminum did.
There is another big advantage to modern aircraft painting techniques. Some of American ‘s older aircraft had several layers of paint rolled on to the wings. When this is removed and the new livery is sprayed on, there is often a significant reduction in weight for older aircraft, even though the entire fuselage is being painted. And even for the newer 737s , the weight added from full-body painting seem to be slight, about 20 lb. in some cases.
These weight reductions or at least weight controls are trivial compared with the fuel savings that will come with the new composite aircraft. But they are a nice side-benefit to a project that began with the prosaic need to paint composites and ended with an attractive and memorable new look for the airlines involved.
Click the link to see the painting process behind American Airlines’ new livery: ow.ly/mau2m.