Go to home depot and find a 72" or longer red oak board w/ straight grain lines on side/sides and straight down what would be the back. If you have a a table saw, band saw, jig saw or a power saw it will make it faster. cut out the shape of bow w/ little extra wood left on bow.
You then scrape the belly side with a rasp,knife,hatchet, planner or a cabinet scraper.
You will need a scale & bow tree/board to make sure the bow doesn't blow up on you. Plus it is a great way to get your bends just right & you hitting your draw weight.