Since this car has already been sealed and painted, the processes are different. There's no phosphate to clean the metal, no Bonderite conversion, no electrocoat, no sealer deck.
In production, when a body comes from the Body Shop, it's nasty. Some steel has formed rust (from a pulled spot welding tip spewing water), spot weld flash and mig weld junk is all over different panels, and people have been handling all the parts with greasy hands and filthy gloves. Sometimes there are gaps between parts because they weren't located perfectly before being spot welded together. No two bodies are the ever the same dimensions, either.
Ford doesn't paint on bare metal because paint is porous and moisture will rust through the paint. We strip the steel with phosphate, then we do a bonderite conversion which causes little mountains of crystals. The car looks streaky and nasty, but straight and clean. Then, we dip in electrocoat. The E-coat sticks to the bonderite, not the steel. That's why a factory paint job is far superior to any other process.
After the car is electrocoated we bake it. Then it goes to the Sealer Deck and Prime, then another bake. The sealer swells like a sponge in some places from curing in the oven but it never hardens. Finally, the primer gets scuffed and dusted, a base & three clearcoats are applied, then the final bake @250*F. The process is tight with temp and humidity within spec's. The prime coat is waterborne, the booths incinerate all exhaust air and overspray is caught floating in water and removed in a separate treatment building. Everyone in the department wears lintless clothes, hair nets paper booties, and are dusted off before entering the paint plant. Dirt is serious business and rarely found because the plant needs to paint a car per minute, so they quadruple-filter the air. The Paint Dept. cannot repaint because of dirt and make money.
Now we get to aftermarket. The process is soooo different, and much more expensive per car. Ford painted the whole body one color, inside each compartment, around each hinged door (trunk lid, hood, etc.) and the outside got painted last. The painters get into a rhythm of repeated motion, 500 times per shift. The paint is constantly recirculating from the Paint Kitchen (so no pressure pots or gun cups). In some areas, he waves the gun upside down (like around bottoms of doors and rocker panels). The cars are on a monorail, hanging on front and rear chains attached to the skids. They are never tilted or tipped up to paint the bottoms (except when they get dipped in E-coat). It's amazing to watch but few 'outsiders' get into the Paint Dept because of dirt and dust they carry. - Dave