First, I wouldn't back ipe with maple. Bamboo or hickory would be my choices. With the one that busted in the other thread, it looked like the maple backing had some grain run-out on it, too. I've seen unbacked ipe bows, if you had a piece with near-perfect grain, it should work. But if it's breaking even with a backing...........What is your drawlength? 60" is pretty short unless you have a pretty short draw. Ipe will handle short lengths if it's well-tillered, but if you're just starting out and all, I'd make them in the 66"-68" range untile you get a few under your belt-much safer. Shorter might keep you from wasting a little bit of wood, but it's all pretty much wasted if it breaks, along with the time you invested. The limb thickness will depend on the width, the individual piece of wood, etc. Make them the thickness that will let them bend some at the floor-tiller stage. Ipe only needs to be an inch or an inch and a quarter wide or so. TB3 has been used succesfully by a lot of people for backing ipe bows, I would go with the TB3 before the marine epoxy. The best glue would be Urac. With any glue, you need to degrease the ipe with acetone or denatured alchohol right before glue-up. Also, I'd throw that tillering stick in the ocean and build a pulley system, and be sure to not pull the bow too far until the tiller is even, and never pull it past your intended draw weight.
