BowEd:
Yes, it's whale baleen. You win the 50 points, duly recorded. They're fully transferable and can be traded with other point holders or used to make purchases in the paleo economy, paleo bitcoin. Just kidding, but not a bad idea.
sleek:
" I have seen baleen used as backing, but does it work as a belly?
Yes. As belly material it stand about half way between horn and bow wood itself. The Asiatic-style bow on page 87 of TBB-1 used baleen on the belly.
PatM:
The glue belly in the photo on the previous page was brushed on. Maybe ten coats. Three layers of TP/glue yields the same thickness, and much more uniformly. It's best to use cheap, thin, almost see-through versions, and to peel its two layers apart, each layer more air than fiber.
Sleek:
Knox Gelatin, and similar, is surprisingly high-quality glue, with a bloom or gel strength of about 300, just about the highest of any glue.