Paints are divided into two broad categories: oil-based paint, also known as alkyd paint, and water-based paints, known as latex paint. Oil-based paint uses petroleum-based solvent as its medium, while latex paint uses water as its medium [source: JoePullaroInc].

There was a time when you could only spray with oil-based paints, since they were thinner than latex paint, did not dry so quickly and did not clog the spray gun's nozzle. But today’s latex paints are made of new synthetic resins, which are compatible with water, have a thinner consistency and are wet enough to be used in a spray gun. Today you can use an airless gun or aerosol can for spray painting with latex paint. However, you still may find that your latex paint is too thick for your spray gun's nozzle and needs thinning. Here's how to thin latex paint so it can be used in a spray gun. Electric Airless Paint Sprayer

Remember, adding water will change the color of the paint and alter the drying time. The water also will necessitate using more coats of paint to achieve the desired finish [source: Sherber].

If you want to get a smooth finish, you may want to spend a little extra money and rent an airless paint sprayer, which doesn’t require you to thin the paint to a precise consistency. Be sure to wear a respirator mask and cover anything around you that might get paint droplets on it [source: Stimpson].

A man named Joseph Binks invented the very first spray gun for paint in 1887. Binks was employed by Marshall Field's in Chicago and part of his job was to paint the walls of the basement in the store. He realized that brushes would take forever and invented the spray gun to make his life a bit easier.

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