they are for building laminated bows. the form is cut to the shape you want the bow. for a recurve, it is like the side view of a recurve. when building a bow, you lay the laminations on it and when the epoxy is on the laminations and riser, you clamp them to the form. when the epoxy dries, the laminations will hold the shape of the form. a heat box is a box around 2x2x8 feet that the bow form that has the laminations clamped to it goes in. the temp gets to about 180 degrees and cures the epoxy to that temp. you leave it in for about 6 hourswith heat on and after 24 hours you take it out and take the bow off the form. when epoxy is cured to a high temp, it takes more heat for the epoxy to fail.