Bending or distorting bowls and vases

[Jon Reiver]

I've had very little success with distorting turnings with steam, boiling or ammonia. I make the turnings between 1/16th and 1/8th inch wall thickness.I've put the turnings in a 2 foot by 2 foot by 2 foot steam box that I made and ran steam from an Earlex steam generator for 8 hours. ( I have two steam generators and alternate them to keep the item steamed) Then put the item in a jig with weights to distort it, no luck. I tried putting the bowl in a press with weights inside the steam box for 8 hours, no luck. I placed the bowl in boiling water for 8 hours, no luck. Same with putting the item in a bucket of household ammonia for 3 days.
Anyone have a solution?
Thanks. Jon

 

[Richard Coers]

How heavy were your weights? How green is the wood? I’m guessing you need a lot more force. Steam bent furniture parts need a full rack of clamps to do the job.

 

[Kevin Jenness]

There's no need to steam wood that thin for that long, you just need to get it up to the boiling point or close to it throughout its thickness. How hot is your box? Get a thermometer in there if you don't have one already. If it's not getting over 205F, insulate it or use both steam generators.

Air dried wood bends better than kiln dried or green wood. What species are you using and how dry is it? If you are turning green wood you might want to let it dry for a day or two before bending.

Some photos of what you are using and trying to do with it might help folks to come up with a solution.

The steambending I have done has been for cabinetmaking and boatbuilding with cedar and cherry in the 1/4" thickness range. An hour was plenty to make the pieces pliable for moderate bending with hand pressure and clamps to maintain the bend. In the photo below the bead molding is steambent while the rails and panel are laminated.

I can't comment on ammonia except that it is toxic and you probably need a higher concentration than you get in household bleach. Steambending is a widely used and tested technique and should work for you with some tweaks.

 

[Richard Coers]

I can't comment on ammonia except that it is toxic and you probably need a higher concentration than you get in household bleach. Steambending is a widely used and tested technique and should work for you with some tweaks.
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I assumed he meant anhydrous ammonia. In a vacuum chamber, anhydrous ammonia will allow extreme bending of wood.

 

[Don Wattenhofer]

Note: that steam bending is always done with the long grain and knots and any other distortions of the grain pattern are avoided.
Turned bowls of course have the full range of grain patterns just due to the fact that they are round, so have you ever heard of any one trying to bend or even make boards out out of end grain?
If you want a distorted bowl start out with a green piece of crotch wood and turn it once down to 1/8th or less and as it dries it is likely to distort, but the particular piece will distort the way it chooses.

Here is an example of natural distortion in paper birch goblet form.

 

[Webb Willmott]

I can't comment on ammonia except that it is toxic and you probably need a higher concentration than you get in household bleach.
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I think you meant household cleaning ammonia. Bleach is sodium hypochlorite. And the two should never be mixed but when they do, they produce chloramine gas (nasty stuff you don’t want to breath).

 

[john lucas]

Look at how they bend cowboy hats. Slow and steady over days.

 

[Don Wattenhofer]

Look at how they bend cowboy hats. Slow and steady over days.

That is also done with green wood. The hat part that goes on your head will naturally go oval as the wood dries just like any side grain bowl, but the brim is encouraged to curl up by the use of rubber bands. At the symposium in State University N Y (SUNY Purchase) I attended the demo by J Mickelson he did not use any steam bending technique and when I got home I made several hats all without the help of extra heat or moisture.

 

[hockenbery]

Look at how they bend cowboy hats. Slow and steady over days.

Like @Don Wattenhofer said. Green wood turned thin bent before it dries. No steam.
Got to take a class Johannes Michelson did for our club. The natural warp is towards oval. Johannes exaggerated the ovalness using clamps with strong rubber bands to push on the sides of the crown to make it more oval and other rubber bands on the brim to pull it up more than it would go on its own.

 

[Darryl Fective]

Sometime I want to try a self-closing hollow form.

Ronald Kanne's video