: I need some advice, or clarification, on the suitibility of luan plywood for
: stitch and glue building.

"Lauan--any of the various Phillipine timbers (as of genera Shorea and Parashorea) that are light yellow to reddish brown or brown, are of moderate strength and durability, and some of which enter commerce as Phillipine mahogany."

I go with the lauan. But do your boil test. There's a fellow near me that builds rowing shells. He's not happy with any of the available plywoods. So he makes his own. I imagine you'll see the same range of opinions here.

I've done three boats in lauan, one traditional the others S&G. In addition, I've built two S&G skiffs in exterior fir ply. I think I now have the courage to tackle a project using a Lloyd's certified product. Both the fir and one lauan project showed minor ply delamination after a few years exposure to the elements. The problem was caused by water wicking into the exposed end grain of the ply at the gunnels. While saturated at build time any panel edge exposed to wear or damage is eventually going to get moisture into it. Generally, kayaks don't have panel edges exposed. They're either glassed or edged with hardwood trim.

Maybe I wouldn't know a void if I saw one, but I've never found anything in lauan like you find in domestic ply. I've been using up a pile of good quality 5mm that I found a few years ago for $5.99 a sheet When it's gone maybe I'll try some of that meranti.