When amateurs apply white paint over the top of orange paint, uneven results tend to occur. To generate an attractive uniform finish, do-it-yourselfers are often forced to apply coat after coat of paint. That can be a time-consuming and costly process. Fortunately, you can improve coverage by applying the right base primer prior to painting.
Why Orange Paint Covers Poorly
Every color of paint contains a white base and a colored pigment. Most paints are made up of between 80 and 90 percent white base. The other 10 to 20 percent represents added pigment that gives the paint its color. Orange paint contains much more pigment than ordinary paint. That characteristic makes it difficult to cover with lighter colors, especially white.
If you apply a single coat of white paint directly over the top of existing orange paint, you will quickly notice bleed-through. A second coat may improve the appearance; however, you're likely to see subtle streaking or discoloration throughout the finish. To generate a uniform finish, you'll likely need to apply between three to four coats of white paint. That can be tedious and expensive. You can eliminate the need for multiple coats by applying a primer.
A white latex primer can drastically improve coverage and reduce the need for multiple coats of white paint. Unfortunately, orange paint is powerful enough to bleed through even the most expensive latex primers. Even after the orange paint is primed, you're likely to need two coats of white paint to generate a uniform finish.
To generate quality coverage with the least number of coats, cover the orange paint with a stain-blocking shellac primer. This type of primer is compatible with both oil and latex paints and can permanently seal and block even the darkest wood stains. After you've applied a coat of shellac primer, you should only need to apply one coat of white paint to achieve full coverage.
Synthetic polyester and nylon paintbrushes are appropriate for applying white latex paint; however, they are not suited for use with stain-blocking shellac primers. Be sure to use a natural-bristled brush when working with shellac primers. Wash those brushes with denatured alcohol. Don't use tap water, or the bristles will lose their shape.