Plywood Guide: Everything You Need to Know - Wood Essentials
Plywood and veneer have a bad reputation, I think it’s because of the home center and all those sheets of sheathing which has warped itself into something resembling a Pringle. But that’s not the only kind of plywood out there, there are many types of all species of wood. It’s a way to stretch expensive wood while also gaining stability.
Plywood is dimensionally stable due to it’s layers of grain going across each other, keeping expansion and contraction to a minimum. By eliminating movement, plywood can be used in places where solid wood is less practical. If you look around your house you will see plywood everywhere. Cabinets, furniture sides and tops, potentially even your engineered hardwood flooring.
A tip for spotting plywood is to look at the end grain. Take my desk as an example. The grain flows across the top and stops, dead ending into a piece of trim with grain going the opposite way. That is a dead giveaway that the builder needed to cover up the ends of plywood with a piece of trim.
Back to my point, plywood isn’t bad. Just take a look at this sheet of slip matched black walnut plywood. It’s gorgeous and also over $200 for a sheet.
For those new to buying fancy plywood, here’s a little about the lingo.
Grading
Plywood is graded on a school scale. A is the best, D is the worst.
A - little to no defects. Good for visible areas.
B - minor flaws requiring work around or repair. Smooth and often ready for paint.
C - visible flaws with knots 1.5 inches in diameter.
D - large flaws and knots 2.5 inches in diameter.
Within the letter grades, they are broken down into usually 4 numbers. A1, A2, A3, and A4. A1 is the best of the A’s, A4 the worst. What distinguishes good versus not good is defects. The more knots and cracks the worse the grade. I wouldn’t suggest going into C and D for furniture. You can to save some money, but you’ll pay for it in time. To paint low grades you will need to spend time doing surface prep, such as filler and sanding.
If you are on a budget, know that each side is graded independently. The first letter/number combination will refer to the front, the second the back. If there is only one letter/number then both sides are the same. You can save a few bucks by buying A1/A4 or B1/B4. Then plan to put the B4 side against a wall or on the bottom of the piece where it will not be as noticeable.
Veneer Cut Methods
For more on these methods, I have a detailed article on the Types of Sawn Lumber. Everything in that article applies to veneer cutting, veneers are just thinner boards. The only cutting method I do not mention is rotary. Rotary cutting is unique to plywood and typically only used for sheathing or for the internal layers of plywood.
Rotary - a log is spun around and the outside is shaved off.
Plain sliced - a log is milled straight down the log.
Quarter sawn - the log is cut into quarters, each quarter is then milled, cutting across the grain, resulting in straight grain in each veneer.
Rift sawn - similar to quarter sawn, but instead of cutting flat along the quartered log, the log is spun to cut in a circle so each board is truly across the grain. Typically only done on oak to remove the medullary rays.
Veneer Matching
Once those veneers are cut, they need to be glued on to a substrate to make plywood. That substrate could be rotary cut veneers of inexpensive wood, MDF, particle board, or a combination. The veneer matching selections are:
Book Match
Slip Match
Pleasing Match
Random Match
Book match - every other veneer is flipped, turning the grain into itself, matching the grainlines and creating a symmetrical pattern across the plywood.
Slip match - veneers are assembled in sequence of cut to give a repeating pattern across the plywood.
Pleasing match - matched by color similarity for a pleasing appearance. Grain may not match.
Random match - assembled without regard of grain or color resulting in no visual continuity between veneers.
Plank match - assembled to appear as though the boards were glued together, sometimes with grooves between veneers.
I hope this short guide helps you select the correct plywood for your project. And if you are unsure about what you need, call or go to a lumberyard and ask for help. Make sure it’s a hardwood dealer, not a construction lumber yard. In the Portland area you want to visit Hardwood Industries or Crosscut Hardwoods, not Parr Lumber who specializes in decking, construction, and trim. For more information on how to find a
Hardwood dealers are knowledgeable people who can match your needs to the correct product. And if they don’t have exactly what you need, they will know where you need to go to get it or will order it for you. Just stay away from the home center. There you will find substandard plywood at a premium price, especially the hardwood ply. Instead, support your local supplier and reap the rewards.