Steam box construction

[CajunRider]

I have one of those Steam Shark thing that I hardly ever use. I'm thinking about connecting it to a steam box for wood bending. Would that work? I wonder if the Steam Shark provides enough steam. What should be the box design?

[tw]

My steam box is a wooden crate built from tongue and groove boards. About 4 metres long and 30x30 centimetres inside. There are some battens nailed crosswise on the bottom of it to keep the wood being steamed off the bottom. The steam pipe is connected through a hole in the bottom halfways along the lenght of the box. The open end of the box has a hinged door.

My steambox did originally contain a camshaft for a Wärtsilä marine engine.... so I have been told.

Downscale or upscale it as you like.

[tlcneeded]

it's interresting that you posted that i just started messing around with bending wood today. i got no clue about the steamer. ill be watch this post.

[TDHofstetter]

Nov 9, 2009 14:52:14 GMT -6 CajunRider said:

I have one of those Steam Shark thing that I hardly ever use. I'm thinking about connecting it to a steam box for wood bending. Would that work? I wonder if the Steam Shark provides enough steam. What should be the box design?

Um... did you have the Shark steam IRON or the Shark steam carpet cleaner or the Shark "steam mop" () or ... ?

It doesn't take any great huge quantity of steam, provided you can keep it coming long enough to heat the wood to temperature. The less steam you have, the tighter the box will need to be, and if you've only got a LITTLE you may need to insulate the box... with styrofoam or polyisocyanurate foam.

The simplest steam box I know of consists of a PVC pipe with a steam inlet at one end & a perforated cap at the other end.

[CajunRider]

How about an insulated PVC pipe with multiple steam inlets along the top. The outlet will be a small nozzle that comes out into a small steam trap that let the condensate out while keeping a low pressure in the system.

[Ruffnek]

CjR,

Hopefully Woodmangler will be along to contribute to this thread as he once bent basket handles every day in his business.

IIRC, he used a new gas can set on a burner...like a fish cooker. The spout on the gas can was connected to a length of PVC with the opposite end angled slightly upward and open. He had placed supports underneath the PVC to prevent it from sagging with the heat and also placed a mesh or something inside to hold the wood elevated a bit.

You fill the can with water, place your wood inside the tube and start the fire going. Marc said that when you think you have enough steam coming out, you aren't even close to having enough yet. You need billows and billows of steam according to him.

When you remove the wood, you have to work quickly as you won't have much time to bend it before it starts becoming brittle again.

Note: some woods (like Ash) bend easily...some don't.

TW - Every dynamic positioned drilling vessel I have ever been on had Wartsila engines powering the thrusters. They must be good.

[Leo Voisine]

When I did a little steam bending this past summer - I used PVC. Make sure there is steam escape holes at the far end - away from the steam source, to allow flow of the steam.

Also - the PVC NEEDS to be supported - else it will droop in the middle when it gets hot.

[sawduster]

I just used a plywood box a little larger than the pieces I was wanting to steam. Rule of thumb for steaming is about an hour per inch of thickness of the wood being bent. I bought an electric tea pot that Lee Valley had for sale some time back. I could barely get an hours worth of steam from it. If you have to stop to refill your boiler, you might as well start all over, so insure that what ever you use to create the steam has the capacity to keep goin for the time you need.

The folks from Homestead Heritage had a display at one of the WWing shows here a while back. One of the fellas from there specializes in Windsor style chairs and he had his steaming set-up there. The steam box was totally sealed, though he had what appeared to be a pressure relief valve on it. If I remember, it was some thick walled (likely high temp) PVC about 3" in diameter. They were bending part(s) for the backrest for the chairs.


Edit In: Went to the Homestead Heritage site and found this little picture of the steamer they use.

[rrich]

When I fume oak (in ammonia fumes) I use a "gas chamber" made from 3/4" melamine. The melamine is rather water proof and if the inlet and outlet are protected from condensation it should work well.