Building a stam "box" for wood bending

[MichaelBikel]

Hey guys,

I am interested in attempting to craft an authentic looking set of snow shoes. This requires me to steam bend the main portion of the wooden frame, which in turn requires a steam box. I would like to minimize the time spent building a steam box so I could focus on the actual snowshoes. Would it be possible for me to use a piece of PVC tubing rather than fabricating a box?

 

[Ehcrain]

I tried to steam bend with a pvc box and the pvc could not handle the high temperature and wouldn't hold shape. I ended up building my box from plywood and lined it with foam. Doing it again is just build it with 1inch foam and tape the seams really well.

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[rlitman]

PVC pipe will soften into something like garden hose when heated with steam.
Foam and tape seems like an ok idea to me.

 

[RPH]

And yet my pvc pipe steam box works fine! Copied the plans from the net, there are some low temperature versions of pipe out there. Make sure to get the higher temp versions.

 

[kbs2244]

The local antique guy just uses one of those old cannon ball looking road construction burners and a piece of downspout.

He builds a support of bricks around the fire to hold up an old cooking pot full of water.
The downspout goes into the water at the low end and rests on a chair back at he high end.
The water boils in the pot, the steam goes into the downspout and a rag stuffed in the high end acts as a plug/steam valve.

He uses it on 1 inch dia oak sticks for "bent back" kitchen chairs.
It is a good sizes pot, so he just fills the pot with water and lets it perk away all night.

He has a demo of a stick tied into a overhand knot hanging on the wall.

 

[ALinCarolina]

I used stove pipe, tea pot, radiator hose, and hot plate.

 

[Gizmosity]

I used a length of PVC pipe for years and years......4" Schedule 40 I assume. I just drilled some 1/4" thru holes every 12" or so for wooden dowels to rest material on. Never had any issues. There's also not much to screwing a scrap pine or plywood (CDX) box together and stuffing rags on the ends. I've seen some really elaborate setups but it doesn't need to be. All my steam boxes were pretty much made from salvaged junk and steam was generated by a wallpaper steamer.

 

[royce]

I use a piece of HDPE pipe and it works good, just make sure to keep the stock in the upper half because the steam really stratifies even in a 4" pipe.
I also use a trough and a weed burner to boil the wood.
You only need to get the wood up to 160 degrees to soften the lignin and get the cellulose to slip.
I've found that when steaming it can get hot enough to cause brittleness if overcooked.
I never had it happen when boiling.

Royce

 

[yhprum]

Try to get green non oven cured wood, it will steam bend much easier. I recall my father made some windsor chairs that the used hand split uncured oak firewood that he steamed in a PVC pipe connected to a pressure cooker (not pressurezed) that worked really well.

 

[Duker]

I used stove pipe, tea pot, radiator hose, and hot plate.

I use a similar setup to this ^^^ I used a new metal gas can versus the tea pot and a propane burner. This fittings were off the shelf at my local hardware store.

 

[TLCObsession]

ABS Pipe works fine.

 

[derosa]

Try to get green non oven cured wood, it will steam bend much easier. I recall my father made some windsor chairs that the used hand split uncured oak firewood that he steamed in a PVC pipe connected to a pressure cooker (not pressurezed) that worked really well.

This is an excellent point as most wood is kiln dried. You can use air dried or seasoned wood but kiln dried does not respond well to steam bending. Best for snow shoes is to find a 6" or so diameter tree and split it. According to one book I have on making them don't use oak though, ash is one of the best woods to use.

 

[royce]

I sure hope you post your build here and after that, maybe a sled is in order, to pull your kit.
Best of luck

Royce

 

[Chris Stapley]

We used to steam bthe no top bows for Ford Model T cars,our setup consisted of a half length of 4" truck exhaust tubing,one end welded shut. It would be inserted in to our bed of coals in the wood stove,half filled with water and let sit and steam our lengths of hardwood for half a day and then the steam ending would begin. Easy ,effective and simple...

 

[MichaelBikel]

A lot of great responses here, thanks guys. If I do actually get around to it I'll post some pics. It's been frustrating watching the snow come down and wishing I had this project done while I actually have the free time.

Oh one more thing, where would you guys get ash for this? Local, online???

 

[McFarmer]

My PVC tube worked fine. I just used hot water, not steam.

 

[MichaelBikel]

Hey guys,
I ended up making a box from wood in the end. After about 30-40 minutes the thermo reads 210-215*F so I am pretty sure I should be able to bend properly. Since I have never done this before I do have a few questions:

How should the grain be oriented?

I am looking to make snowshoes which calls for white ash, I am wondering what thickness range I can bend in.

How long would you recommend I leave the piece in the box for before attempting to bend?

I understand that some of the answers depend on specifics, and I have read some of this info on the net elsewhere. I am just looking to get a solid idea from GJers since I know we are a capable bunch.

Thanks!

PS does anyone know where I could find white ash staves? Online or local???

 

[2oolhound]

This is interesting. I just finished watching "Kayla a cry in the wilderness" on youtube. The story about a boy who's dad was an arctic explorer. Among his possessions was a journal with plans for a dog sled which the kid makes. At 58:30 and again at 59:30 in the movie you can see the setup the kids used to steam the wood and a bit of the sled construction follows. You might find it interesting. Here's the youtube link:

Are you planning to make cross country (long, narrow pointy ones) or bear paws?

 

[royce]

Hey guys,
I ended up making a box from wood in the end. After about 30-40 minutes the thermo reads 210-215*F so I am pretty sure I should be able to bend properly. Since I have never done this before I do have a few questions:

How should the grain be oriented?

I am looking to make snowshoes which calls for white ash, I am wondering what thickness range I can bend in.

How long would you recommend I leave the piece in the box for before attempting to bend?

I understand that some of the answers depend on specifics, and I have read some of this info on the net elsewhere. I am just looking to get a solid idea from GJers since I know we are a capable bunch.

Thanks!

PS does anyone know where I could find white ash staves? Online or local???

I'll take a stab at this,

Wood can be bent in any direction, for a snowshoe it needs bent both with and perpendicular to the grain.
The bigger issue is making sure the grain does not run out, because it will be far more prone to breaking if it runs out.
Pick the straightest vertical grain timber you can find.
The easiest way to insure the grain does not run out, is to split it,then plane the split side and then lay out the cuts from that edge.

You can bend any thickness you want.
Wooden ships had massive bent frames in them, for example.
I'll post a pic of a full 1"x2"white oak stem and a 1"x1-1/2" 160 degree yellow cedar breasthook.

A good starting point for steaming is 15 minutes per 1/4" thickness
The time needs adjusted to the wood being used and moisture content.
Myself, I like to soak the wood in water for a few days before I steam or boil it to bend it, because I don't have access to green wood

Hope this helps

Royce

 

[SlappyWhite]

Use an eaves trough down-spout, metal cheap and easy.

 

[brianh]

lots of good info I have done a lot of laminated layer glue ups in bends.

Going to have to give steaming a shot.

 

[royce]

lots of good info I have done a lot of laminated layer glue ups in bends.

Going to have to give steaming a shot.

Brian,
Bending opens up a whole new world for building with wood.
I have found it as satisfying as anything I have ever done, when it goes well.
With that said, it is as frustrating as anything I've tried to do, when it goes poorly.
One thing I've learned is to buy extra wood and be ready to have some failures in the beginning.
As a example, my wife and I were bending these ribs for a boat and the first 6 or 8 of them broke.
We were bending them in place, with out a form and they were all breaking on my side.
Something I was doing was not working and I watched her and adapted her technique and we never broke another, on that job.
With experience, you can feel when the wood is right to bend and the limitations of the stock.
I love bending wood and bet you will too.
Royce

 

[brianh]

Royce, thanks for the tips I mill a lot of my own lumber so I can try with some green from the start, I have enough stuff laying around to make a steamer this is a good time of the year for me to play around a little before I get super busy in the spring.