When you build the bow and the laminations are on the form, they are taped down on the form. An air hose about 3" diam is laid on top of the lams and the top half of the form goes on top of the hose. the top of the form is then connected to the bottom part with metal strips screwed onto the form sides. When it is connected, the hose is connected to the air compressor and it is turned on to about 60lbs psi. They cost about $100. Im going to need to get one for my next bow. Try this link. they have everything you need
http://www.binghamprojects.com/kits.htm