Many wood projects require bent wood. The techniques are commonly required in boat building but can be useful in many other types of woodworking. A steam box is simply a container where the wood is placed while absorbing the steam. Builders can use a simple tea kettle for small projects or larger, more complex steam generators for larger steam boxes.
Build a support for a 2-inch diameter, 8 foot long, PVC pipe from 2 by 4 inch lumber. The support must support the pipe along its entire length to prevent the pipe from bending when it is warmed by the steam, according to the Wood Canoe Heritage Society.
Place a hotplate and tea kettle at one end of the pipe. Attach the spout of the tea kettle to the end of the pipe using radiator hose, clamps and appropriate pipe size reduction fittings.
Cap other end of the PVC pipe with a fitting. Drill a 1/4-inch hole in this fitting to allow the steam pressure to vent rather than build to a dangerous level within the PVC pipe steam box.
Construct the steam box from 2 by 12 inch, 18 feet long, using galvanised 3-inch deck screws. Close one end of the box with a 2 by 12 inch board cut to fit and with a appropriate sized hole for the steam pipe.
Attach the boiler, a heat source of about 50,000 BTU coupled with a 5 gallon water container is suggested by the Wood Canoe Heritage Society. Use radiator hose to move the steam from the water container to the steam box.
Fit a 2 by 12 inch board to the other end of the box. A removable end allows placement and removal of the wood without disturbing the steam generator and hose assembly on the other end of the steam box.
The steam boxes should not be airtight and some steam will escape. Allow one hour of steaming for each inch of thickness of the wood. Place the wood in the steam box after the boiler has generated a steam box full of steam.
Hot wood and steam can cause burns. Wear gloves, goggles and other protective gear when working with steamed wood.