Friday, August 7, 2009

A Wood Steaming Box

One of the pieces of wood in the Parks collection looks like a bent rib from a kayak. (Its the piece of wood with the green discolouration that I alluded to in an early copper post, that I intend to use verdigris to stain.) The Tuktut Nogait bow also has bent recurves in each limb, so I will need to do some wood bending this summer. Yesterday I got started by building a wood steaming box.

I built the box out of scraps of plywood left over from when I built the workshop. There are dowels running through the middle of the box to support the wood that is being steamed. The steam is an electric tea kettle with a short section of washer drain pipe connected to the bottom of the box. I went with an electric kettle because I didn't want to have to use a stove or flame to heat the kettle. Electric kettles all have auto-off features which shut them off as soon as they start to steam. You need to disable that switch to get the kettle to boil continuously, which means its really important to keep a close eye on the kettle while its working.

I played around with the box yesterday to see how it would all work and if the washing machine hose would melt or the kettle would burst into flames. So far, so good. There are holes around the edge of the lid that I need to plug with rags, I had too much steam escaping. Its important to have some venting so that the pressure doesn't build up too much inside, but it needs to get good and hot inside.

I need to build a jig to match the angle of the bend that I need. The idea is to steam the wood and then quickly clamp it into the shape you want it to take when it is dry. I'll post with updates if it works. If it doesn't, I'll probably just avoid the subject and go look for curved sticks to carve.

Photo Credits: Tim Rast

Photo Caption:
Top: Probable Kayak Rib from a collection of Inuvialuit artifacts
Second: Wood steaming box
Third: Boiling kettle, attached to Washing Machine drain hose
Bottom: Inside the box - the end of the hose comes up through the floor and the wood to be steamed is suspended on dowels.


  1. Was it just a clamp issue? I wonder if all that might be required is to soak the wood in water overnight before clamping it to dry in the sun? I've seen the lumber we used for building our deck warp like crazy when it dried out in the sun.

  2. The wood split along some growth rings running diagnolly through the rib. It was a weak spot that gave way because I wasn't using clamps to slowly bend the wood into shape, I was levering the wood into shape by hand and I think that it just failed at the weakest point, rather than bend where I wanted it to.

    It didn't crack all the way through and I compared it to the original today. I think I can shave off the split wood and still have enough mass to make the reproduction. I'll get a second shot at bending this piece in the next day or two. I'll try to correct my mistakes from the first attempt.


Related Posts with Thumbnails