Determine the use of the plywood. The finish for plywood will vary depending on the use of the plywood, exterior or interior. If the plywood use is for interior, you can use a variety of finishes. However, if the use of the plywood is exterior, only one method to finish the plywood is recommended.
Select the type of plywood finish. You can use a variety of finishes for plywood, including rough finishes and sanded finishes. Sanded plywood will usually have repairs made to it with different synthetic putties. If you use a wood stain or clear coat finish on sanded plywood, you will want to use the smoothest type of plywood with the fewest repairs. Southern pine plywood will have fewer repaired patches than the Douglas fir plywood. Rough plywood is not suitable for stains or clear coat finishes. You should paint this type of plywood. Veneer is the smooth side of plywood and will not have issues with putty repairs. You can use a variety of paints, finishes and stains on veneer.
Choose from semi-transparent or opaque stains, clear coats or paints for sanded plywood for interiors. On rough plywood, use a primer and paint. For exterior uses, you should use only an opaque stain or a primer and top coat of paint. Use 100 percent acrylic resin latex for the longest lasting performance.
Prepare the area where you are finishing the plywood. Put down drop cloths around and under the plywood you are finishing. Tape off the areas that should be protected from the finish.
Apply two coats of the finish you have chosen. Use a paintbrush to apply it for maximum penetration. You can use a roller if you are finishing a large area as long as you use pressure on the roller to get the stain into the surface of the plywood. Do not use a sprayer because it will not provide enough penetration into the plywood. When finishing exterior plywood, it is important to finish the edges with extra care because plywood is a composite wood and if water leaks into the edge it can damage it.