5 Attachment(s)
Making a Toboggan (illustrating the steam bending process)
Earlier this month, I attended a toboggan making course at my local Lee Valley store.
It was a two part course. During the first part, we steamed and bent the wood then, a week later; we took the wood off the forms, and assembled the toboggans. Everyone attending the course exited with a toboggan and, for a small additional charge to cover material, I exited with the bent wood that will allow me to build a second toboggan in the future.
The main purpose of the course was to learn to steam and bend wood, producing a toboggan was just a bonus. The course was taught by John Robinson who is a well known Windsor Chair craftsman. John teaches chair making classes in both Canada and the USA and some of his chairs have been featured in Fine Woodworking.
We made the toboggans with relatively green ash that John cut on his bandsaw shortly before the course.
The toboggan making process is best illustrated with pictures. Five are attached to this post and more will follow in the next post.
(1) We first marked the ash to show best orientation and position of cross pieces. Then we planed the edges and scraped the sides a bit. Next, the boards were placed into the (home made) steam box.
(2) The boards were steamed for about an hour. Here is another view of the box.
(3) The boards were (very carefully) bent over a circular form
(4) Then, they were tied down. That's John Robinson in the background.
(5) Finally, the boards were clamped in a couple of places. This assembly was allowed to dry for a week.
Don't use kiln-dried wood
Quote:
Originally Posted by Frank Pellow
Lou, yes it was a lot of fun!
Our instructor said that most kiln dried wood will not steam properly because most kiln drying is rushed resulting in "case hardened" wood. Air dried should be OK. I guess that properly kiln dried would be OK if you could get it.
After making the above response, I decided to read the detailed hand-out that we had been given when attending the course. It turns out that no kiln dried wood should be steam bent. Here is a quaote from the handout:
Kiln-dried wood must not be used; the lignin in the wood has been permanently set during the hot dry kilning process. No amount of steaming or soaking will weeken the lignum bond sufficienntly for sucessful bending. The same applies for air dried wood that has been allowed to dry and stabilize below 10% moisture content.