Rusting happens at spots where the paint has worn thin or has been scratched.This small section may allow moist air to “creep” under the adjoining intact paint film and result in corrosion under it. Paints & Coatings are used to form a barrier and to prevent the metal from coming in contact with the moist air. Rusting requires the presence of oxygen and water, which must come in contact with the bare metal.
However, it can “creep” or be “accelerated”. Rust is not a biological entity so it can not “multiply”. Dramatic language but scientifically incorrect! Sometimes rust is referred to as a cancer or a virus that spreads unabated.
