Bending wood is an old craft developed to meet the needs of everything from furniture to barrels to boats and ships. There are a few techniques available to the amateur carpenter, and choosing which method depends on what kind of wood you are looking to bend. The most popular method for bending cedar is by way of low-pressure steaming. Although it may take practice to get it right, using a steam box at home as a method to bend cedar is easy enough for just about anyone to master.
Glue two 6 1/2 inch by 4 foot by 3/4 inch plywood planks together. This will form the bottom of the steam box.
Glue your 5 inch by 4 foot by 3/4 inch and 8 inch by 4 foot plywood planks together so that the 5 inch wide plank is directly in the centre of the 8 inch plank, leaving 1 1/2 inch rebating steps on both sides to form the lap joint. This will form the side of your steam box.
Join these glued sides together by shouldering the plank with the rebate into the smaller plank. This is half of your box. Use staples to fasten the planks together tightly.
Drill two 10mm holes into the bottom plank of your half box---one in the direct centre of the bottom plank, and the other 6 inches short of the end and centred.
Drill 2 1/2mm holes every 2 or 3 inches into the copper tubing.
Insert each of the copper tubes into the copper t-joint.
Vice crimp the other ends of the cobber tubes.
Drill holes in each of the dadoes wide enough to run the copper tubing through.
Run your 10mm copper tubing through the centre holes of each of your dadoes.
Lay the dadoes flat on the bottom of your half-box with the small holes in the copper tubing facing the sides and the t-joint centred so that it funnels into the hole pre-drilled into your box's bottom plank. Space the dadoes evenly to provide support for the cedar wood you will steam.
Repeat Steps 1--3 with your other planks of wood. This will be the second half of your box. Apply glue to the rebates and fit this into the corresponding rebates to complete your box. Use staples to fasten it more tightly.
Glue your 5 inch by 5 inch square of plywood in the direct centre of your 8 inch by 8 inch square of plywood, leaving 3 inch rebate steps on all sides. Fasten this at the end of the box nearest to where you drilled the 10mm hole.
Repeat Step 6 with your second 5 inch by 5 inch and 8 inch by 8 inch squares of plywood, but instead of fixing this to the other open end, install this using your steel hinge. This will be the door you will use to throw in the cedar you will steam.
Install the box to an open wall in a safe clear area using L-braces. Position the L-braces so the steam box tilts down at a very slight angle---this will allow for condensation to escape out the second hole you pre-drilled into your bottom plank.
Position a wallpaper removal steamer below the steam box and run your plastic piping from the steam source into the opening on the bottom of your box where the copper t-joint is positioned.
Run your other plastic hose from the hole that is 6 inches short of the end into a plastic bucket. The condensed waste water will flow through this hose into the bucket.
Construct a jig by drilling guides made from spare blocks of wood onto a square of plywood. Position the guides along the plywood at the angle you would like your wood to take after you steam it.
Place your cedar strips along the dadoes and close the lid of your steam box.
Run the wallpaper removal steamer (or whichever steam source you choose) so that the steam runs through the plastic tubing into the steam box.
Allow the wood to soften. The amount of time it takes for your wood to be sufficiently steamed in order to bend varies depending on the thickness of the wood. A general rule of thumb is to steam the wood for an hour for each inch of thickness, but cedar, being such a soft wood, will only require 2 minutes for every 1/4 inch of thickness.
Carefully remove the cedar planks from the steam box once the wood is sufficiently pliable.
Bend the wood immediately after you have removed it from the steamer and fix it to the jig guides with your clamps. Let the wood sit in the clamps for a day or two.
Wood bending might be considered an art, and the same could be said about bending cedar. You might not get it right the first time, but after a couple of trials, you will be well on your way to being a competent wood bender.
Although low-pressure steam bending is safer than other bending methods, it does entail dangerously hot steam. Take adequate precautions to protect yourself from being burnt.