Composition Wallboard. Composition wallboard usually presents no particular painting difficulties if the ordinary precautions are observed, such as making certain that the surface is dry and free from grease and oil. The painting procedure for wallboard is the same as for plaster; it requires a priming and sealing coat followed by whatever finishes coats are desired, or may be given one-coat flat or resin-emulsion type paint. Cheaper then doing it yourself. Some would argue that if you're going to all the trouble to fully prep the car yourself, then why not just shoot the paint as well? Why get a shop involved? The answer is simply that you'll get a better job and for less money. Some would argue with this, but the fact is that if you've never sprayed a car before then your first car will have a steep, and expensive learning curve. Laying down an even, consistent coat of paint takes considerable practice. Also, paint and equipment is not cheap. You'll need to buy primer, color coat, clear coat, reducers & catalysts. None of these are inexpensive and you can easily spend as much in paint materials alone as the cheapest paint job at Maaco or similar shop. Knock down texture is basically a orange peel that is sprayed on and allowed to "set-up" for a minute or two then gently "knocked down" by running a 6" drywall knife over it, "knocking down" the surface of the texture. Although knock down is a flattened version of orange peel, I suggest you do not use a spray can of orange peel, the knock down comes in its own spray can and the results are much better, again experiment before spraying it on the wall. However, If ever you apply any of the textures to the wall and are not satisfied with the results, wash the texture off immediately before it dries, then allow the wall to dry and try it again. Once you have the texture applied to your liking and you have allowed it to dry, you may want to paint the patches a couple of time before painting the entire wall, especially for walls where the paint to be applied will have some sheen. Multiple coats on these areas will make them blend in, unnoticeable, with the rest of the wall. You will know if the patches need more coats of paint, because the patch/texture will have absorbed the paint causing the spot to look duller than the rest of the existing wall.
For stippling you need a special brush; get one that is flat, and has short, stiff bristles. The principal ingredient in whitewash is lime paste. A satisfactory paste can be made with hydrated lime, but better results are obtained by using quicklime paste that has been slaked with enough water to make it moderately stiff. The lime paste should be kept in a loosely covered container for at least several days. Eight gallons of stiff lime paste can be made by slaking 25 lbs. of quicklime in 10 gallons of water, or by soaking 50 lbs. of hydrated lime in 6 gallons of water. After soaking, the paste should be strained through a fine screen to remove lumps or foreign matter. 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. If a desired shade is not obtainable in custom-or ready-mixed paints, white paints may be tinted with colors-in-oil. To do this, mix the color-in-oil with a small amount of turpentine or mineral spirits and stir this into the white paint, a little at a time. If a blended color is desired, more than one color may be added, such as a chrome green and chrome yellow pigments to produce a lettuce green shade.