Well this weekend I tried to bend the crest rail do my back stool but things did not go great.
First the bending form needed to be built. I glued up two pairs of boards and then cut them into curves which were then glued together.
I then used the oscillating spindle sander to smooth out the curves. The piece of wood then went into a roasting pan for 75 min per the Anarchists Design book’s instructions. When I placed the board into the form I had considerable difficulty compressing the form and soon hard the sound of cracking.
I think there were several problems; the wood is likely driver than I intended as I had planned to steam bend months ago. Secondly, the wood sank in the water so it was more of a boil than a steam (this euclyptus globulus is denser than water). Finally, the grain was not straight and the split was right where a grain line crossed the edge of the board.
Next weekend I will build an actual steam box and I’ll make sure the grain is straight.
thewoodworkingconsultant 
[…] edit: At least I’m not the only one having bending issues… […]
LikeLike
Ouch 😦
Had similar fun myself this weekend: http://www.stochasticgeometry.ie/2016/12/12/depressing-weekend-results/
Mind you, your jig looks a lot better than mine did. Maybe try the polythene tubing approach? It’s a lot more hassle-free than the whole build-a-steambox-and-bend-the-wood-inside-of-20-seconds approach…
LikeLike
That was the plan, 4 inch Pvc and end caps with a wallpaper steamer.
LikeLike
No, not PVC pipe, polythene tube. The soft, flexible, make-custom-sized-plastic-bags-using-a-heat-sealer type of stuff. You cut a length of it that’s as long as your piece of wood plus a few feet on either end, then put the hose into the middle of the tube, steam the wood in the tubing, bend it while still steaming it, leave it rest on the bending jig while still steaming, then kill the steam off and leave it cool on the jig for a while, then you take it off the jig and out of the tube, towel off the surface and then clamp it to a drying jig for a few days or a week. Be sure to use a bending strap as well (it stays outside the bag). You can take your time on the actual bend (say, 40 minutes to bend instead of under 20 seconds) and you can let the wood stay hot while bent so the tensions settle out while the lignin is still warm, so you get way less springback.
It’s not perfect – I’ve had failures too – but I’ve been able to successfully bend kiln-dried american black walnut without presoaking around a 105 degree bend on a 10.3 inch radius (and then pushed it back to 90 degrees round a 12 inch radius on the drying rig to counter springback). And storage is very easy, you either discard the plastic tubing or you roll or fold it up and put it in a drawer at the end.
LikeLike
huh, that’s an interesting idea
LikeLike