Choosing Plywood for Dummies

Hardwood plywood

If you've ever tried to buy solid wood for a finished product, you may still be suffering from sticker shock: our house woodworker once paid about $25 (on sale) for a chunk of walnut about 8 x 12 x 22 – and those measurements were in inches! Ditto the cost of even cheap pine, if it's clear and knot-free. That's why, for many projects, everyone from DIY woodworkers to major furniture- and cabinet-makers uses plywood. If you're new to the topic, though, you might want some basic information, say, "How to Choose Plywood"¹; but don't expect to get the good stuff from Jan Goldfield at eHow.com...

Oh, heck, anyone can pull up a commercial lumber website and perform a copy-reword-paste job on the four grades of plywood surfaces – A, B, C and D – with all the various specification about sanding; size of knots, cracks and blemishes; and the method(s) for patching. That's pretty much what Goldfield did; although where she came up with her opening statement and why she thought it pertinent remain a mystery:

"Plywood, untreated, survived the floods of Hurricane Katrina. That, all by itself, makes it a valuable building material." Moving right along, Jan blathered briefly about the number of plies (without mentioning number of plies vs. thickness) before she got to the meat of the matter, the grades. Our self-appointed plywood expert said, "Plywood carries a two-letter rating of quality. It tell us the grade of the face side and the backside of the plywood. A-grade means a face free of knots; B and C-grades have limited blemishes; D-grade can have open holes."

Well, sort of: Jan apparently didn't notice that an A grade also means that it's been sanded, which also reduces the thickness by about 1/32nd inch (not to mention that plywood doesn't have a "backside," it has a back side). Some furniture-grade BC is also sanded. After that omission, Goldfield moved on to explain the two-and three-letter nomenclature, in which she "explained" that

"You may run across C-D-X plywood. The X says the plywood is a [sic] exterior grade."

Ummm, not quite: the X in CDX (the industry doesn't use those hyphens, Jan) means that the glue is moisture resistant and so the plywood is suitable for brief outdoor exposure. If you want outdoor plywood, you have to select treated plywood or marine plywood, neither of which Goldfield found it necessary to mention. She also said zip about hardwood plywood...

That's what happens when you ask a "freelance garden writer" to explain lumber to you – although I would, frankly, expect a self-appointed garden expert to have a better handle on plywood for outdoor use. But no, and that's just one of the reasons Jan's getting herself a Dumbass of the Day award.

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/how_4424236_choose-plywood.html

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