Dave Emerson replies: Steam box design depends on what you’re bending. A few requirements are that the steam must flow through. A vent is required. The volume of steam is critical. Material to bend needs to be on a rack in the box. Also, the design of the box must not cool the steam. Lee Valley-Veritas designed jigging for bending and supplied the best booklet on bending I’ve seen. It’s no longer in the catalog but might still be available. It’s not worth investing the considerable time and learning trial and error. Necessary, unless you’re doing multiples. Instead, laminate for predictable results. Way back there’s a video of my steam bending demo.