Est. 1998 — 27 years of woodworking knowledge
steam bending question
McKay
>I am helping one of my students bend some wood for a rocker. The rocker bent well and seemed to keep its shape, The back splat however, sprung back 3/8" on each end. I have found pieces of wood in the scrap pile with a better bend. How long should we leave the wood in the bending forms after steaming? Is 24 hrs enough? Do we need to turn a fan on it? What say ye? Thanks in advance.
Re: steam bending question
thomd
>back slats are often put directly into a chair, trimed to a length where they retain their bow.
The amount of time required to make a "part", something that holds it's shape out of a form, is the amount of time required for the part to dry. While a steamed part is not terrybly wet, it's likely going to take longer than 24 hours, perhaps as long as a week or even longer. Of course a person making tons of parts could take all that into account and prefigure the amount of movement.
What also counts is how well bent the part is. I am not suggesting extreme methods should be required when bending a slat, but if one does use such tools as straps etc, downy, and a really hot soak in the steam..., anything that actually forces the greatest shift possible into the fibers, then that part will spring back the least.
Re: steam bending question
Ted Wong
>This is a timely subject. I'm doing a woodbending workshop in a couple of weeks myself. And as I prepare I've done a lot of right angle bends. Some of the bends I did before Christmas were 90 degrees with a 4" radius. After taking them off the bending form (about 30 minutes) I didn't have a cooling or drying form to put them in so I just used clamps to pinch the ends until I maintend the 90 degree bend. Two weeks later I come back to them and they had actually sprung in the opposite direction I thought they would, I had a bunch of pieces with 80 -85 degree bends in them. No problem, I just held the bent portion of the pieces above the steam kettle for about 10 - 15 minutes apiece and tweaked them back to 90 degrees.
Now we are doing some more extreme bends, 2" radius 90 degree bends in 1/2" thick material. This time I'm following Michael Fortunes directions pretty much verbatim and have a set of cooling forms to clamp the pieces to so they will maintain the bend I want. Michael suggests leaving the pieces in the form for 1 - 2 weeks.