I've done a couple ash bows from boards but, I laminated a hickory backing on them as insurance.
Ash can make a selfbow but, it must be approx. 64" long, 2" to 2 1/2" wide & at the fades & tapper to 1/2" at the tips. Or you could probably go 72" long and 1 3/4" at the fades tappering to 3/8" tips.
There are several more experienced here on ash stave bows. So, do a search here on the "Bowyers Bench" or in the "How To" section and I bet you'll find some good info on ash selfbows.
There are several build-alongs in progress right now in this section. Even though these staves are osage bows, the principles are still about the same. You just need to go wider with whitewoods like ash.