There are two main basic formulations of paint, latex and oil. Oil paints
are the more traditional paints, and have been around for a very long time. Latex
paints are a more recent innovation, and one that has been embraced by a vast
number of people.
OIL: Oil based paints, also known as "alkyd" paints, are generally thought of
as a more penetrating paint. The oils that the paint uses tend to go deeper into the
pores of the surface you paint, and bond at a deeper level. The down side is that they
can yellow over the years, and that in order to clean it up, you need to have paint thinner,
turpentine, or other mineral spirits at hand. And just because oils penetrate deeper into
the substrate (i.e. into the wood or whatever), it does not mean that an alkyd paint will
never peel. Most paints will peel if water gets under them, or from weathering through time.
LATEX: Latex based paints bond to the surface, and so are useful for a number of applications.
They provide a good seal at the surface, and maintain their color well through time, without the
yellowing alkyd paints are known to have. They clean up with water, and dry in a relatively short
amount of time. These are the main reasons so many people have opted to use latex paints, especially
inside their homes. (see Interior vs. Exterior)
Which over what?
Perhaps the biggest question people have is whether one sort of paint can go over another. For a long
time, conventional wisdom said that if you started with oil, stick with oil, and if you started with a
latex-based paint, stick with latex. Several years ago, this was changed slightly. Now, the "word on
the street" is:
Latex paint can go over an oil based paint. Oil paint should only go over an oil paint.
Or, simply put, latex can go over most sorts of paint, but oils should only go over oils.
Of course, there are plenty of different opinions about this, and there are many people
who will
put anything over anything, and have no problems. Still, manufacturer recommendations are
to
put like over like, or latex over both.
