I always thought that hide glue (or knox gelatin) was the only options for sinew...and not the "bottled" kind either. I built a half dozen bows this way...the way everyone said it should be done. Well boys, I'm here to tell you old dogs can learn new tricks. This fall, I built two sinew backed bows using titebond 3, and they work superbly...and yes, the sinew still shrinks and draws your bow into reflex. I still like the way hide glue "gels" quickly when applying sinew...but there is a lot to be said about titebond 3 and the longer working time...and the less mess...and the ability to work it at room temperature...and the inherent weatherproofing it adds to the finished product. Both bows I built were mid-sixties in weight, and both are great shooters.
Ed Scott, of Owl Bows clued me into using this, and I have to give him the credit...and that man builds some real works of art in sinew.
I doubt I'll use hide glue anymore...seriously!
Here's a couple pics of the bows....I killed a couple deer with the flatbow. The other is a static recurve that is as fast as most glass bows. Both are 58" long, nock to nock, strung.