I made quite a few years back and the only thing i would add is that you can use closet pole which works perfectly There's two sizes, use the smaller diameter one. I used a jig saw and cut a gentle curved shape out of the ends and then clamped and epoxied the blades in. Then I put a small filet on both sides of the back. I did some nice ones with glass and strip blades etc. but a basic good paddle can be made with the closet pole and 1/4 ply blades.