Steamers and wood bending

[kevinmoelk]

As many of you know I have an old wood stove that I'm trying to put to use in some fashion. Today I was thinking about building something to enable me to steam bend wood. I was wondering if anyone has built a steam bender, and if so was it wood fired?

My thought would be to have a long trough, a container for water on the stove which would produce steam and introduce the steam into the enclosed trough. There would be a regulator on the trough of course, and a rack inside for the wood to sit on, so it's not soaked in water.

I'm not sure a woodstove would be the most effective water heater, and thinking maybe I should develop a gas fired or electric element for the steam generation.

Just trying to find a way to save the old stove from the dump I guess.

-Kevin

 

[My_3_Girls]

Kevin,

I've seen situations where it has been done, mostly with normal plumbing stuff. You could probably use a pressure cooker pot, some copper pipe, and a 6" or 8" stove pipe for the steam chamber. Upsizing from that, you could use regular duct work (8"x24"?) as the steam chamber. You only need to get the water up to 212 degrees to make steam, stove tops are usually much more than that. With that said, I've never built one! I have thought of trying to make a meat smoker out of an old wood stove, or even a new vozelgang (!)

 

[Martin Strand III]

For the purists out there, and our planet, it is suggested you don't burn in an "old" stove, please.

Interesting project, though.

Aye,
Marty

 

[sailor61]

as a wooden boat owner I've spent some time around steamboxes for bending wood.

your idea sounds pretty correct. however, getting enough steam off a wood fired heater may be difficult. Generally the guys around here have rigged up temporary hearths to hold the steam generator (old large pressure cooker or similar) and come up with a way to support a propane fired roofing torch to use as a heat source. You might try "woodenboat.com" for more info - not sure what they have online for magazine archives.

 

[sailor61]

additionally, the steambox it self is generally plywood and the connecting hose tot he steam vessel is usually an old piece of a good quality garden hose. you need to maintain as much heat as possible to avoid condensation in the line or box.

 

[Andre B.]

Ideally the stove has one flat top with a rear smoke exit, but even if it is a step top this will work just will not have as much heating surface.

Get some good clear (no knots or cracks) 1 x 6 boards, pine, poplar, basswood does not matter much.

Use the boards to make the sides of a box the size of the heating surface.
Glue this box down to the stove top with some cheap latex based silicone sealant, use it on the joints of the wood box also. We have found on our maple syrup cooker that the cheap stuff holds up to the heat better then the pure silicone stuff. As long as there is water in it the stove top will not get very hot.

If you have a top vent stove and have to go around the pipe with the box you will need to put some insulation between the pipe and the wood to keep it from burning.
Now fit a sheet metal top on the box, again seal with the latex sealant and use some small nails, one every inch or so to hold it down.

Drill a 1" hole in the side near the top, this is to add water and a place to put the steam pipe/hose.
You could get fancy and add a water level gage and a place to add water without removing the steam hose.

If you let it run out of water the sealant between the wood sides and the stove top will over heat and let go and the wood could even start burning.
The construction should come apart before any significant pressure can build up but you could get a lot of boiling water spraying around, inconvenient PITA at best, trip to the ER for some little kid with 2nd and 3rd degree burns to the face at worst.

So it is up to YOU as designer, builder, and operator not to allow any pressure to build up. I am just suggesting an idea.

 

[restorer]

I've built and used two bending boxes. I used an old pressure cooker, leave the pressure relief valve in place for safety. Pressure cooker is connected to box with a 3 ft piece of stainless flexible gas connector. Box on first unit was wood, but second was a length of 3 in. galvanized pipe. Capped on far end with a standard flat cap, cooker side was capped with a bell reducer (you'll need to get this at a plumbing supply house. Reducer should be threaded to fit stainless flex. Flat cap should have a 3/4 in. tapped hole to thread a standard water tap into it.

You need to generate heat. A three foot pipe unit will need lots of heat. We used a Coleman stove with both burners blasting away. You need to create the steam and keep the pipe hot. The cap and valve at the outer end is the door to the box. The valve on the end is to control pressure and allow the steam to pass through the tube. I use a slotted scrap of wood to act as a shelf inside. If you are bending anything larger than a 1X3 board, you'll need something even larger. I was bending one inch slats for chairs, so this worked great. Thinner boards, bend better. Greenwood bends best.

By the way, if some pressure is allowed, say 5-6 lbs. the time in the steamer is dramatically reduced. So, don't use a pressure cooker that doesn't have a gauge that works.