How to Finish Plywood
Plywood is a versatile, cost-efficient, and therefore popular building material. It is frequently used for many interior and exterior purposes, and methods for finishing plywood vary between uses.
Step 1 - Determine the Use
Each finish for plywood will vary depending on whether the wood is for exterior purposes or interior purposes. If the use is interior, several different finishing possibilities exist. However, if the plywood is to be used for an exterior purpose, there is a single recommended way to finish the wood.
Step 2 - Determine Type of Plywood Finish
There are a number of plywood grades and finishes. Some are rough, and some have a sanded finish. There are a few more expensive types of plywood that have a veneer finish and give the nicest look for interior applications.
Sanded plywood often has repairs made to it with different synthetic putties. If you are going to use a wood stain or clear coat finish on this type of wood, then you will want to find the smoothest type of wood with the fewest number of repairs. Putties do not finish in the same way that wood does, and the stain or sealant will not penetrate repaired areas. Plywood made of Southern pine will often have fewer repaired patches than plywood made of Douglas fir. Repairs tend to be smaller as well.
Rough plywood isn’t suited for stains or clear-coat finishes and should be painted. Veneers don’t have issues with putty repairs and can accept a variety of stains, clear coat finishes, or paints.
Step 3 - Choose Your Finishing Material
If you are using sanded plywood for an interior application, you can choose from semitransparent or opaque stains, clear coats, or paint. If you are using rough cut plywood, then a primer and paint is recommended. For exterior applications, you should use only an opaque stain or a primer/topcoat paint system. Whichever you choose, you should be sure to use 100 percent acrylic resin latex for the longest-lasting performance.
Step 4 - Prepare the Area
As with painting any items, use drop cloths underneath and around the item to be painted. Also, tape off any areas that need to be protected.
Step 5 - Paint the Area
For interior applications, use two coats of whatever finishing stain you’ve chosen, or a stain inhibiting primer and topcoat for paint.
For staining an exterior piece of plywood, you should use, at the minimum, two coats of opaque stain, preferably applied with a brush for maximum penetration. If you are working with a large area, then you may be tempted to use a roller. This can be done only if you are careful to use pressure on the roller to get stain into every surface. Avoid using a sprayer, as it does not provide adequate penetration into the wood.
If you are using paint instead of stain on either interior or exterior pieces, then use at least one coat of primer, ideally applied with a brush. A roller is acceptable, but it needs at least two layers of topcoat for the best results.
Tip: With exterior plywood, it is extremely important to finish the edges with great care, since plywood is composite wood, and if water leaches into the edges, it can cause quick mold and rot.
Finishing plywood requires a little more thought and preparation than finishing solid wood, but it can be easily accomplished with a little work.