To protect the metal from rust on a steel car. On an aluminum, or carbon fiber car it is not necessary to paint the car. As an example all DeLorean's were not painted from the factory as the body panels were made of aluminum.
Most of them are not painted they are wrapped!
90% of the cars are painted white.
by a machine
No.
some painted one once
Yes, you can. It has been used to polish painted surfaces on cars and motorcycles for a long time now.
cars are smooth because they are sanded down and then spray painted with nylon paint
Primer is under the paint.
SO they don't rust.
Some were painted with a brush, some were dip painted, and some were spray painted.
coz they want to look nice*and if their not painted their look boring , &besides if the cars are not painted maybe the owner of the car will know the car ,if you know if i mean !*
they were painted black with a red nazi symbol