The stiffener former is placed in position on the gelled laminate and the reinforcement is built up layer by layer as a continuous process. Frames are usually a solid or hollow core former covered with several layers of reinforcement forming a close box or semi-circular section when combined with the hull laminate . these are known as "hat" and "half round". the material of the former is chosen for light weight , workability ,inertness,ability to with and laminating prossure and economy . Solid cores are normally of formed plastics of the desired profile and do not contribute to the strength. they are bedded on resin putty . paper rope former is to be used only on small boats.