You scuff up existing paint for two reasons. First, you want to get rid of any oil, grease or dirt trapped in the top layer of paint. This is the stuff that cleaners and degreasers can't get off. The second reason to scuff is to set up a physical bond for the new primer and paint to adhere to. You want to give the old paint some tooth so the new sticks better.
OK, let's get started. Step one...supplies. You need a flat brush, a fan, a small detail brush and a couple of Filberts. A filbert is a rounded edge brush that lets you maneuver the paint easily without going outside the edges. Ultimately buy brushes that you like though, and make them work. Fans allow you to blend, for example. I use fans a lot and it's how I graduate color throughout my images. Everything I paint is by hand....no airbrushing or assistants. I want it to be an expression of me and nobody else. You also need an oil painting medium to mix with the oil paint to make it more fluid, and to speed or slow the drying process. Whichever you prefer. Go to the art store and don't be afraid to ask for help....they'll love helping you! A medium is merely an additive liquid which increases gloss, makes it flow easily, preserves the finish over time, keeps it from yellowing. I personally love Galkyd and Galkyd Lite. If that isn't available, buy a medium that looks like liquid amber and is kind of thick. Don't buy watery looking mediums....too hard to work with.
Water-thinned rubber-latex paint is already an old reliable, though it is only about 10 years old. It accounts for a big percentage of all paint sold and is still the most widely available of the easy-to-use finishes. One new type is a combination vinyl-rubber paint that is said to do a better job on interiors than either vinyl or rubber alone because it dries faster, lasts longer and has less sheen.
"Boxing" is a good method of mixing paints. Since paint is a mixture of solids and liquids, it is important that it be mixed thoroughly before using. To do this, the greater portion of the liquid contents of the can should be poured in a clean bucket somewhat larger than the paint can. Then, with a stiff paddle, the settled pigment in the original container should be loosened and any lumps broken up. After this, mix the material in the container thoroughly, using a figure 8 motion, and follow with a lifting and beating motion. Continue stirring the mixture vigorously while slowly adding the liquid that was previously poured off the top. Complete the mixing by pouring the paint back and forth from one container to the other several times until the entire amount is of uniform consistency.
Better still, you don't have to spend hours getting ready and hours cleaning up afterward. Premixed paints, electric-drill attachments and self-dispensing calking guns make short work of preparation. Cleaning up is a soap-and-water job for the rubber paints, or a quick dip in special cleaners for the oils. Disposable dropcloths and paper paint pails are used once and thrown away.
Technical advancements are constantly being made to improve the life span, durability, wear and performance of exterior paints. The Akrylatfarg range at Ray Munn, for example, is an environmentally sound water-based option.
So lets start with Warm and Cool. When thinking about Warm, think about a desert panorama of gold, brown and earth tones. When thinking about Cool think of colors in the artic such as gray, black, white or think of the deep blue sea such as deep blues, blue greens and turquoise. Everyone can wear just about any color, the difference is in the shade of the color. When thinking of clothing, makeup or accessories, visualize Cool as a color with a drop of silvery-blue. Visualize Warm as a color with a drop of gold. For example, if you put a drop of gold to a red sweater it becomes a Warm red, but if you put a drop of silvery blue it becomes a Cool red.