So, I started making a red oak-backed maple board bow, 63" ntn pulling around 40-45 lbs (I'm guessing as I don't have a scale) Everything was going great, I had it to draw length at 28", and was going through the fourth round of exercise when I heard a crack... It was just a tiny little splinter lifting on the back, so I backed it with linen. I was exercising it again, probably around the 3rd round, when I got a whole lateral crack along the oak backing... i put a rawhide patch on it, and it holds, but probably not for long, it's hinging a little bit... so sad. I thought about using my heat gun to delaminate the oak and put a new backing on it. My tiller was pretty too! I'll post picks if I can get them off my phone.