Masonry Walls and Ceilings. Interior masonry walls and ceilings above grade may, in general, be painted in much the same manner as plaster surfaces. Here again, it is necessary to allow adequate time for the masonry to dry before applying paint and, in addition, attention should be given to the preparation of the surface. When decorating a wall containing Portland cement (concrete, for example), it is essential to take precautions against the attack of alkali. For this purpose, alkali-resistant primers such as rubber-base paints may be used when oil paints are to follow. Basically what you're looking for is a good, solid foundation of existing paint that is stable and still strongly bonded to the car. Many times an original factory paint job, even after decades will meet these criteria. Fortunately, you can always get your primer tinted for free. Getting your primer colored the same as your paint will save you a coat of paint. Of course, I always recommend doing a minimum of 2 coats of paint so that your finish sheen looks consistent.
The second part of preparation is surface prep, it addresses covering the surfaces you do not want to get any paint on. A little plastic sheeting will go along way to keeping paint off of floors, window coverings, handrails, cabinets, counter tops, etc... And, if you are not confident with your ability to paint a straight line next to door casing, baseboards, cabinets or hardware protect these surfaces using masking tape. There are two basic types of masking tape white/yellow and blue. The white tape sticks to surfaces better but, can pull off finishes on cabinets or stained woodwork. Blue tape usually will not pull off finishes but, does not stick as well, this will probably be the tape to use for most applications. Always wipe down or dust the surface you will be masking to assure the best tape adhesion possible. If you use blue tape you may need to re-rub down the tape before painting next to it, only mask off areas with blue tape that you will be painting for a given day. With either tapes, do not assume the are a force field that paint will not penetrate, use them as a reference and dry brush the paint next to the edge of the tape and avoid soaking the edge of the tape with a lot of paint, this will cause the paint to "bleed" through giving you an undesired look. If you will need to apply multiple coats of paint, on the first coat, paint as close to the tape as you can, not really getting paint on the tape. With the second coat or a one coat application, you can use the tape more of like a paint barrier and get a little more paint on the tape if you immediately remove each section of tape after painting the section, this will keep the paint from sitting on the tape and "bleeding" behind it. Also, if you get a lot of paint on the tape it is not good to let the paint dry on the tape because some paints (especially the glossier paints) will peel if allowed to dried, with the tape when it is pulled off. White tape should not be left on for longer than a couple of days and I suggest not leaving it on more than a day in areas that receive long periods of direct sunlight. Blue tape can be left on for days, if it will stay on, there again it does not stick as well and may need rubbed down again immediately before painting up next to it. Color - The paint makers are out to sell the lady of the house and color is their come-on. They are tempting her with a kaleidoscope's variety; one firm offers more than 6,000 different shades. For localities where such conditions exist, self-cleaning paints should be selected. These paints are usually so designated on the label. Concrete, plaster, and metal surfaces each present special problems in painting. For instance, paint for use on masonry or new plaster must be resistant to dampness and alkalies, and paints used on steel must have rust-inhibitive properties. The reality is that the guys shooting paint, even at the cheapest shops, know how to do it. They spray a dozen cars a week and have plenty of practice laying down smooth, consistent coats of paint. They work quickly and efficiently because they have to or they don't make money. They don't really make their money on shooting paint. They profit from body work because it takes time and insurance work because it pays well.