For future reference, Ipe differs A LOT from one board to the next. I've made self-bows from Ipe that held up just fine from one batch of wood and then couldn't get even a backed bow from another batch. It is also very difficult to read the grain on it. It can be quite difficult to glue up as well due to the oils and sometimes it will spring off a lam and shatters itself. I know a lot of people make BBI bows now and am sure there would be someone who could let you know how to ID a good piece of Ipe from a crap piece.The only thing I noticed from the good batch that I bought is that it wasn't as dense as the second batch, it was easier to work and had a more reddish-brown colour. A good BBI bow is supposed to be one of the best possible combinations for a laminated bow, so it is worth trying again.
