Steam bending kiln dried oak?

[Jim Martin]

Hello All;

A buddy of mine is building some chairs with steam bent arms. He is using

1/4 sawn kiln dried white oak and is having a heck of a time getting them to bend. I have read conflicting opinions on whether or not kiln fried wood will bend (he does not need much of a bend). Any of you have luck steam bending kiln dried wood? Was there a trick to it? Maybe you steam longer than the 1 hour per inch of thickness rule of themb? In my own experience I have bent green oak and then years later bent wood from the same batch (I guess by then it was air dried because I live in Utah where 20% rh is considered muggy). The air dried behaved a little differently but not too much.

Thanks in advance,

Jim

[Frank McVey]

I've had good luck with steam-bending green timber, preferably ash. Less so with air-dried, and very little with kiln-dried.

Cheers

Frank

[George]

Oak is probably more vulnerable to kiln degrade than other woods because of the rays, which are natural places for splits to form and run.

Green rived is best, green sawn is all right. After a few cycles, even air-dried gets some internal "set" to it.

Can your friend laminate the arms? On the quarter, it can be done almost invisibly.

[Phisherman]

Cut the oak into 1/4" strips. The strips will bend much easier. After removing the dried strips from the bending jig, glue them up and put them back into the jig. The laminate will make the steam bent arms all that much stronger. (This is how they make graceful and strong banisters for curvy staircases.)

[Dave W]

In my experience, steam bending kiln dried oak seldom works. Better to go to a local sawmill and get green wood. Dave

[Icepick]

Soak in water for 3 or 4 days . No guarantee that it will work but it has for me.

[Robert Smith]

"Jim Martin" wrote in message news:ccng4r$fpe$ [e-mail]...

I have been bending kiln dried oak a lot lately for making various types of basket handles. When I first began my "trials and tribulations" I had a heck of a time. I was told by someone that I had to steam it an hour per 1/4 of thickness. I was attempting to bend a piece of 3/4 x 1 oak into a 6" radius. the thick side is the one being bent. I failed a number of times, then I had a brain storm. I thought it was probably to dry to start with so I took a few pieces of the cut stock, tied a rope around it and threw it in the creek behind my house. It lived there for 6 days, ( the following Saturday). I took it out of the creek, steamed it and put it in the forming jig. It began taking the shape wonderfully, but then SNAP, some of the grain let loose and it cracked. It didn't crack alot, but enough to make fire wood. Then I had another brain storm ( with all the open space between my ears, there seems to be alot of space for weather systems to move on through). I figgered that the wood outside of the neutral axis had to stretch to accommodate the longer circumference, after all the difference in circumference from a 12" circle to a 14" circle is 6 9/32. So I bought some .030 thk. stainless shim stock. I fastened two 1/2 thick blocks of stainless to each end, with the distance between the blocks being the exact length of my blanks. (You have to make sure they a fastened securely, I just used machine screws the first time, but they didn't hold the blocks well enough. I then drilled and reamed holes through the whole assembly, and pressed in some 3/8 dia. dowel pins. They don't move now.) Then after I steamed the blanks, I put it in the shim stock and bent it around my form. Eureka, no cracks. So now I always support the outside of my blanks before I attempt to bend them. I use .01 thk. shim stock for bending thinner pieces of wood. I still let really dry wood soak in the crick for a few days before bending. And a major problem I have is you that you must let the wood dry in the bending form. If you take it out and set it some where, some of the bend leaves it, and it will warp all c*ck-eyed. Although I have bent Cherry with excellent results, without supporting the outer edge.

[Steven J Kelty]