A real old fashioned method for making small parts and cowls involves making the buck and layup as already described, but mount the buck on a healthy piece of dowel. Clamp the dowel and the plug in a vise. Layup the glass or whatever, then inflate a large toy balloon and press it down on the buck, slowly letting the air out until the balloon is turned inside out over the piece. Let dry and peel the baloon off. Makes a pretty slick finish and reduces the amount of after-work.