I knew from the beginning that the restoration of this Old Town canoe would require us to practice some wood steam-bending. This is a technique in woodworking where boards are exposed to steam in order to soften the wood fibers, allowing the entire board to be molded into new shapes. Once the boards are cooled, the wood will hold its new shape. This is how certain parts of the canoe were constructed, notably the many ribs which help form the frame of the canoe. Steam-bending wood can be used for several numerous other projects.
It was time for us to build a wooden steam-bending box. With this box, we would be able to steam wood for other projects such as the construction of furniture like rocking chairs, wine racks etc.
I purchased the Rockler steam bending kit, which includes plans as well as hardware for the construction of a steambox and then the actual steam generator and tubing. The construction of the box itself is simple. It doesn’t have to be pretty, only functional. This box will also be subjected to extreme temperatures and humidities so it will take a beating. It can be constructed out of either solid wood or plywood (external). If you decide to use plywood, make sure it is for external grade plywood as regular plywood would simply delaminate once you use the steambox.
My brother recently had to tear down sections of a wall in his house so he had a pile of scrap pine that we used. Nothing better than reusing old wood and giving it new purpose. In the restoration of this canoe, the largest rib that we would have to bend measures at nearly 4.5 feet. So the dimensions of our box was roughly 5′ by 5.5″. In general, for this size of steam generator, Rockler did not recommend creating a box longer than 5ft and with sides no longer than 6 inches. For larger steam boxes, you would might consider having a larger reservoir of water.
The construction of this box is very straightforward. Basically, no wood glue is to be used because of the constant stress of expansion and contraction that the box will be under. Outdoor screws will do the job to hold together your box. Screws will also allow you to take apart the box if you should need to replace any sides. At the end of the box, a brass fitting is installed where the tubing will connect to from the steam generator. The front of the box, is a lid with a latch, sealed with weather stripping. Using a forstner bit, I drilled holes along the box with evenly spaced dowels to serve as a resting rack for the piece of wood to be steamed. The wooden board that you steam should ideally be elevated, so that the steam can circulate around the whole board. Remember, water will accumulate on the bottom of the box so a drainage hole should also be placed. This steam box will leak regardless, so either have a water collection bucket or steam outdoors.
After using some scrap pieces and a pocket hole jig, we attached some feet to the box for some stability. After a quick test on a small piece of pine, she is ready to go! Next step, damage assessment and materials ordering.
Happy New Year Everyone! Be safe and healthy!