|Review by JJohnston||posted 03-14-2010 10:56 PM||15504 views||0 times favorited||11 comments|
I thought I’d try a new (to me) product I found at my local “good” lumberyard – “lumber core plywood” – to build a few utility-grade shop projects. It’s made of solid lumber pieces laminated with thin face veneers. The core pieces are tongue-and-groove joined along their edges, which you can see in the first picture (if you can’t make out the part in focus, look below and to the right at the piece in the clamps. You can see the contrast between a light and a dark piece).
This seems great at first glance, but there’s a problem: only the pieces on the edges are the full length of the sheet. The interior pieces are of random lengths, and the ends are simply butted – there are even little gaps. See the second picture with a utility knife for scale. This edge is parallel to the long dimension of the sheet. The edge below it is the factory edge, which looks continuous and beautiful.
This construction method SERIOUSLY compromises the bending strength. The piece in the second picture was going to be a shelf, but with those two gaps, which are typical, I have serious reservations about using it – in fact, I’m not going to. Since the core pieces are of random lengths, and are edge-jointed, the problem isn’t so bad on a wide piece (more continuity), but it gets worse as you rip it narrower. About the only suitable application I can see for this material is as big pieces subject to edge-to-edge compression, like sides for a base cabinet or a cabinet-style bench.
There is one upside: it’s light, probably because it isn’t all soaked through with glue, like conventional plywood.
-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln