Originally posted by Montague
If you want the absolute lightest way to sheet over wood ribs, the old "yellow" resins (wood glues) are the best by far. Ask an old free-flighter who's been around since before CA about it 
(that's not me, but I've seen it done. Takes patience though, over night drying and all that)
I built my first plane entirely with household white glue (12 years ago) to save the cost of glues. It took forever to dry, but it penetrates the wood very well, and once it dries is extremely light and strong.
It survived some pretty rough "landings".
