I’m coming along with the upper case for my 18th century highboy. I’m now trying to make the curved top for the piece. I thought I would use 1/8 inch plywood and then apply veneer on top of that. So I built a steam box for heating up the plywood pieces. I’m using a kettle, hot plate and a radiator hose to pump steam into the box. I’ve also built a form for forcing the plywood pieces into the correct shape. So far…two trys and two busts. They always crack when I attempt to bend them.These plywood pieces are approximately 16×17 inches and 1/8 inch thick.
How long are you supposed to leave them in the steam box and at what temperature?
Thanks!
Jim
Replies
Plywood cannot be steam bent. The glue holding the plys together is not going to soften when heated. There is a bendable plywood product called wiggle wood. It comes in a range of thicknesses from 1/8" to 3/8". This plywood will greatly simplify making your parts.
Jim,
You know, they didn't use much 1/8" plywood in the 18th century ;-) What was used was softwood, typically yellow or white pine, or poplar, depending on the region where the piece originated. Generally about 1/8", and wet on one side or the other, to induce enough warp to get it in place. Clamp in the rabbets where it is going to be, or in your bending forms, and allow to dry. It probably will split at some point after it is glued/nailed in place, as the old ones have done. If this bothers you, bending plywood, with an appropriate veneer on the show face would be a good alternative, as already suggested.
Ray
Sorry to disappoint all the purists out there but...I'm not that concerned about using 18th century materials and techniques to build this piece. I thought that the glue on plywood would soften up if subjected to the right temperature long enough. Maybe not? Since this has to be one solid sheet...cutting 1/8 inch slices of a 16x17 inch pine...poplar or any other board is beyond my skill set and I dare to say 95% of all woodworkers. So...someone suggested a product called wiggly wood or bendable plywood...I'll give that a try...if I can locate a source.
Jim
How tight is your radius?
I do a lot of the type of form bending you've described using both thin pieces of solid wood and plywood. This should work easily without steaming down to a radius of 12".
You can purchase pre-laminated curved and radiused plywood in various shapes and sizes. I've used this type of product before with good results.
Another method would be to cooper a tube using sixteen staves cut with an 11-1/4 degree bevel on each side. The width of the stave will determine the radius.
If you are interested I can offer more detail and photos later.
Bret
I made a highboy a few years ago and used the following procedure to make the curved section. I planed pieces of poplar down to 1/8" and edge-glued them to make the right size pieces. Then I glued a piece of muslin to the underside of the pieces. I used a roller to get a good bond across the wood. This kept them from cracking. I carefully bent them into the correct shape and attached the with screws. Hope this helps.
Jim
Cut kerfs!
What about cutting kerfs in the plywood every 1/4" or so stopping at the last ply then bending it? I've done this before when i've run out of the bendable plywood....
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