New England Chowder Bowl - Fusible Glass Slumping Molds Mold measures approx. 6" Dia. x 3" H. To use, simply pretreat the mold with kiln wash or nitride spray, and slump your prefused or sheet glass (cut to size) using the included New Hampshire Craftworks firing schedule. For best results, always elevate this mold off the kiln shelf by at least 1" before firing as shown (kiln posts and glass are not included in this listing).