One of my goals of the “Furniture of Necessity” is to encourage people to build things that look complex but are actually simple once you know the trick. Think: compound joinery without a single numeral or calculation. Or, in today’s case, make curved parts using raw materials from the grocery store.
Steam-bending wood is fun and easy. And I own a steambox, a steam generator and all the clamps and forms that make it a snap. But that’s a lot of money and effort if you want to make one steamed part, such as a simple crest rail for a chair or backstool.
When I first learned to make Shaker boxes from John Wilson more than a decade ago, we boiled the parts in a steel planter box that was heated by a hot plate. That works pretty well, though you have to monitor the temperature to keep it boiling.
Another way to bend wood without fussing over the temperature is to use my mother’s recipe for beef brisket.
She would seal the brisket in a roasting pan covered in foil and cook it in the oven until the meat fell apart on your fork.
So I went to the grocery on Friday and picked up a bundle of firewood ($3.99) and a roasting pan ($2). The firewood is all split stuff that is 14” to 16” long and air-dried. My bundle of wood had oak, ash, poplar and sappy walnut. All the stock was about 30 percent moisture content – plenty dry enough to use for this operation.
I managed to get three crest rails from a split of oak and planed them all four-square. I preheated the oven to 450° F. Then I filled my aluminum roasting pan with hot water, put the oak in and sealed the pan with two layers of aluminum foil. I cut a small 1/2” slit in the top and roasted the oak in the oven for 75 minutes. Then I took it to my bending form.
My bending form is made from a stack of 3/4” MDF that’s glued together. The easiest way to bend a 3/4” crest rail is using the help of a bench vise. I clamped half the form to the jaw of my vise and the other half to the bench.
I dropped the oak between the two parts of the form and cranked the vise closed. Simple. I then put two bar clamps across the form and removed it from the vise. In two days I’ll take the clamps off and I’ll have another crest rail for my next chair.
— Christopher Schwarz
26 thoughts on “The $2 Steambox”
Do you have any lessons learned from the crest rail you blogged about cracking several weeks ago? Is this the same method?
That was a totally different investigation. It involved soaking kiln-dried wood and then attempting to steam-bend it. The only lesson there was this: Two days is not a long enough soak.
I have steam bent bone dry oak with runout grain by vacuum soaking for an hour then steaming. A box is made from PVC pipe, and encap and a plug end with a vacuum attachment, I used a venturi with compressed air, which soaked the wood in short order.
There are no issues with using MDF in the form? Painful experience with cheap furniture has taught me that moisture and MDF combine with terrible results. But obviously this works. I’m impressed.
I’m sure if you soaked the MDF it would fall apart. But there really isn’t that much moisture involved. I have MDF forms that are 10 years old.
If you still don’t like the idea, use CDX ply or coat the MDF with linseed oil (that “oil and water don’t mix thing”).
Good sir, The crest rail was made from firewood…i.e. “Limb wood”…?
Steam bending a la casserole…brilliant!
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Yup. Plain old firewood. No clue if it was reaction wood or compression wood. All three crests bent fine.
How much spring back did you need to account for?
With steam bending, I have found there is little (if any) springback. In fact, sometimes the bend continues to tighten after being released.
I get significant springback with bent laminations and compwood, however. There are formulas for those based on the radius of the bend.
Now that I can afford.
Hmmm Next thing you know
you’ll be showing us the Vincent Price method
of steam bending Ash…
Is there much spring back? John Previti
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Nope. There’s another comment above where I address this.
Awesome. I wasn’t going to build a chair because of the extra cost of the materials involved for steam bending. It’s on the list now. Like the wood source too.
I have no experience with steam bending, perhaps like others because building a PVC pipe steamer seemed like a biggish project. So this looks very interesting.
A question: It seems that many texts on the subject highlight the need to steam and not boil the wood, hence the bolts to suspend the wood and the drainage holes in PVC pipe plans (e.g. Mike Dunbar’s version).
In this method, you submerge the wood in water and “cook” it. Have you found any difference concerning method or results vis-à-vis the “normal” way?
I guess I’ll have to go back and read those texts now and see what I’m doing wrong.
Both methods are more about applying heat. It’s the heat that makes the wood plastic. (This is why you can use a heat gun, hair dryer, hot pipe or a clothes iron to bend wood.) The moisture is a way of delivering the heat and preventing scorching.
Boiling wood is commonly done in the veneer industry. The boles are boiled for days (or weeks) before slicing to assist the cutting.
In other words, there is no difference between steaming and boiling in my experience.
And now to check Dunbar’s book….
Thanks for your answer.
As I mentioned, I have no experience with steam bending, only with small “limbering and forcing” bends.So I would be thrilled, if you have found a better way.
I am just wondering why anyone would go with the hassle and danger associated with a steam box, if a simple water bath which, as you have shown, anyone can make in their kitchen oven?
I purchased the ebook version of Chairmaker’s Notebook from you (Wonderful book!). Here Galbert shows two steam setups – both with dowels for support and drainage holes.
The same goes for the Mike Dunbar “Ultimate Steam Box” and in the setup shown in the Veritas Tools folder on steaming.
On the other hand, none of these talk about WHY they use steam instead of water…
(Could it be because prolonged water contact might discolour or weaken the wood (e.g. washing out the softened lignin?)
Thanks again – and sorry if I’m adding to the confusion.
– Confused in Copenhagen
The advantage of just using heat is that the lignin ( the stifferner in wood) is weakened without water swelling the cellulose. My slats are just 1/8″ thick. Would heat work on thicker stock?
This is friekin awesome. Thanks for always keeping in mind those of us on a really tight budget. Can’t wait to give this a try.
Could one prep the wood for steam bending with a pressure cooker? You use the example of the brisket in the foil pan. I may have to give this a go soon and report back. Don’t have a foil pan, but do have a pressure cooker (and it seems like it would take far less time)…
I’ve had pretty good luck steam bending small pieces by wrapping them in a wet cloth and throwing them in the microwave. Probably a lot more risky. I do it in increments so as to avoid not setting the wood on fire.
I also highly recommend watching the Tips from a Shipwright video on Youtube that shows a way to steam bend wood in place on the side of a boat. These videos are sponsored by Jamestown Distributors. Boat builder Louis Sauzedde rocks! It doesn’t matter if you don’t care about boats, this guy is very imaginative.
I also should have mentioned that the main reason people build steam boxes is to help bend pieces that won’t fit in an oven or microwave.
Will any of these experiments make there way to the Lie-Nielsen event at Popwood? It might be a good way to get more buttocks in the chairs as well.
How thick was the crest rail?
Your timing on this post really couldn’t have been better, I was literally sitting down to put together a shopping list for a steambox on Sunday when I saw this post. I just gave this a try last night, but with kiln dried oak I’d had soaking for three days.
In my excitement to build one your backstools I forgot to plane the crest rail down to 3/4″ before soaking so I had a 1″ part to bend. It worked like a charm! This is my first time steam bending and it’s kinda weird watching a board bend like that in the form without breaking…
Thanks for sharing all the notes you’ve posted about Furniture of Necessity. I’ve not been this excited about a woodworking book since Campaign Furniture came out!
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