Tutorial ~ How To Make a Hollow Concrete Sphere
May 03, 2012· Inflatable ball: Exercise balls are recommended but the play ball I purchased for from Walmart has endured the creation of three spheres without a problem. Soft beach balls cannot be used because the ball needs to be rigid enough to support the weight of the layers of concrete without sagging. Whichever ball you choose to use, it''s imperative the ball stays fully inflated during the ...