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Using steam to straighten maple

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Forum topic by MikeFromCanmore posted 11-18-2019 01:18 AM 558 views 1 time favorited 18 replies Add to Favorites Watch
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MikeFromCanmore

26 posts in 1366 days


11-18-2019 01:18 AM

Topic tags/keywords: steam straightening maple

I have some planks of air-dried (many years) maple. They are rough cut to about 1 1/4 inch thick. After removing the rough saw marks and cutting and planing to approximate size (3/4×3 x 80 inches), they have become bowed. This bow is too large to remove with a jointer – I would lose too much thickness, and my jointer is too short anyway.

So I wonder if I could remove the bow by steaming the boards and clamping them into a straight line. It seems like a no-brainer, but I have never done any steaming. Read about it, but never done it.

Comments?

-- If they can get you asking the wrong questions, they don't have to worry about the answers.


18 replies so far

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BobAnderton

308 posts in 3352 days


#1 posted 11-18-2019 03:44 PM

Does your project require 80” long parts? Cut to length before you try to straighten/flatten. Does the structure of the project help to pull the bow out? For instance, something like a dresser or bookcase has enough structure that you can pull things straight with adjoining members at right angles to it.

-- Bob Anderton - Austin, TX - Nova 3000 lathe, Alaskan Mark III mill, Husqavarna Saw

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BobAnderton

308 posts in 3352 days


#2 posted 11-19-2019 12:10 AM

Oh, sorry, I should have asked, by bow do you mean cupping, where the boards curve across their width, or bow, where the boards curve along their length. I assumed you mean bow as they are only 3” wide.

-- Bob Anderton - Austin, TX - Nova 3000 lathe, Alaskan Mark III mill, Husqavarna Saw

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AlaskaGuy

5436 posts in 2871 days


#3 posted 11-19-2019 12:27 AM

-- Alaskan's for Global warming!

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wildwoodbybrianjohns

539 posts in 109 days


#4 posted 11-19-2019 07:03 AM


- AlaskaGuy

Everybody is doing a brand new dance now, come on baby, do the bow crook kink cup twist….........

-- Wildwood by Brian Johns: It is wiser to find out, than to suppose (S. Clemens)

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MikeFromCanmore

26 posts in 1366 days


#5 posted 11-19-2019 10:43 PM



- AlaskaGuy


A combination of bow and crook.

-- If they can get you asking the wrong questions, they don't have to worry about the answers.

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MikeFromCanmore

26 posts in 1366 days


#6 posted 11-19-2019 10:46 PM



Does your project require 80” long parts? Cut to length before you try to straighten/flatten. Does the structure of the project help to pull the bow out? For instance, something like a dresser or bookcase has enough structure that you can pull things straight with adjoining members at right angles to it.

- BobAnderton


Yes, in this case 80 inches is needed. There may be some help from the structure, but the degree of curvature makes me think I don’t want to rely on structure to straighten it fully.

-- If they can get you asking the wrong questions, they don't have to worry about the answers.

View corelz125's profile

corelz125

921 posts in 1538 days


#7 posted 11-19-2019 11:49 PM

One article in one of the woodworking magazines I read awhile back the author said the best tool for bowed and twisted wood is the fire place. If you steam the wood what will keep it from twisting after it has dried again?

View JerryMaldonato's profile

JerryMaldonato

46 posts in 885 days


#8 posted 11-20-2019 12:15 AM

This comes from a Flexner article. I have used it successfully, but the board was about half as long as yours. It did work though.

The idea is to wet the wood thoroughly on the convex side of the bow. It seems counterintuitive since that will make the cells swell and increase the bow. However the trick is to then weight the board while set on supports at each end and let it dry while slightly bowed in the opposite direction. What happens is that the wood cells dry out and become rigid again, but have been slightly compressed by the bend and stay that way. It’s a guessing game how much bend to have it dry with. I placed two 3/4” boards on my bench and set the bowed board with the bow up and that face very wet and then used some bricks I keep around that are wrapped in duct tape and placed them in the middle. I added enough weight so the middle of the board was resting on my bench and left it for several days so it was completely dry. It took the bow out. I would guess that if it wasn’t perfect the first time you could keep trying with more or less bend.

Best of luck.

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MikeFromCanmore

26 posts in 1366 days


#9 posted 11-20-2019 07:21 PM



One article in one of the woodworking magazines I read awhile back the author said the best tool for bowed and twisted wood is the fire place. If you steam the wood what will keep it from twisting after it has dried again?

- corelz125


That’s a fair question, and I don’t have a good answer. I have read, though, that people steam wood to introduce a permanent bend. They hold it in place while it is drying, and it seems to keep the shape when the clamps are removed.

-- If they can get you asking the wrong questions, they don't have to worry about the answers.

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MikeFromCanmore

26 posts in 1366 days


#10 posted 11-20-2019 07:23 PM



This comes from a Flexner article. I have used it successfully, but the board was about half as long as yours. It did work though.

The idea is to wet the wood thoroughly on the convex side of the bow. It seems counterintuitive since that will make the cells swell and increase the bow. However the trick is to then weight the board while set on supports at each end and let it dry while slightly bowed in the opposite direction. What happens is that the wood cells dry out and become rigid again, but have been slightly compressed by the bend and stay that way. It s a guessing game how much bend to have it dry with. I placed two 3/4” boards on my bench and set the bowed board with the bow up and that face very wet and then used some bricks I keep around that are wrapped in duct tape and placed them in the middle. I added enough weight so the middle of the board was resting on my bench and left it for several days so it was completely dry. It took the bow out. I would guess that if it wasn t perfect the first time you could keep trying with more or less bend.

Best of luck.

- JerryMaldonato


Worth a try. Thanks.

-- If they can get you asking the wrong questions, they don't have to worry about the answers.

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corelz125

921 posts in 1538 days


#11 posted 11-21-2019 02:23 AM

Are you going to try it? I would like to hear how it turns out.

View Toller's profile

Toller

48 posts in 2162 days


#12 posted 11-21-2019 02:55 AM

I had a 7’ length of walnut with a 1” bow in it. I needed it straight.

I clamped it to a Ibeam with a 1” reverse curve and steamed it like that, repeatedly. After 1 year (yes, 365 days) I unclamped it and with went back immediately to how it originally.

Good luck.

View therealSteveN's profile

therealSteveN

4318 posts in 1136 days


#13 posted 11-21-2019 04:36 AM



I have some planks of air-dried (many years) maple. They are rough cut to about 1 1/4 inch thick. After removing the rough saw marks and cutting and planing to approximate size (3/4×3 x 80 inches), they have become bowed. This bow is too large to remove with a jointer – I would lose too much thickness, and my jointer is too short anyway.

So I wonder if I could remove the bow by steaming the boards and clamping them into a straight line. It seems like a no-brainer, but I have never done any steaming. Read about it, but never done it.

Comments?

- MikeFromCanmore

The answer to cut them into shorter lengths, and prep them 4square from there is the best I know of. But if you need the length, what ya gonna do???? If you are going to steam them please follow up, maybe with pics to let everyone know what happens.

In my head I don’t think it will work, especially hearing it happened after you opened up a board, and then pooof they crooked on you. Typically that tells me these thicker boards were not as dry in the center as the outside. Cutting into them you exposed that wetter wood, and it did the presto chango thing. My belief is adding more water won’t make them spring back. If somehow you could add more dryness, you might be on to something. I think they call that a kiln :-) After the fact it probably wouldn’t be worth the cost, but if you do need the length, some have reported a sort of kiln drying with putting the wood inside a black plastic bad, closed air tight. Allow the sun to heat it. Absolutely the wrong time of year for most of that though, unless you are real South.

I’ve tried the Flexner thing, way before I ever saw it in writing, it’s an ages old idea. It incorporates SUN (heat) and dampness from the yard. Kinda like shooting dice, sometimes ya get a 6, sometimes you don’t. If you’re betting on the 6, it almost never happens. When you absolutely don’t care, well lookit that it’s flat again…

-- Think safe, be safe

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MikeFromCanmore

26 posts in 1366 days


#14 posted 11-21-2019 07:07 PM



Are you going to try it? I would like to hear how it turns out.

- corelz125


Yes, I am going to try it. My neighbour tells me that he and a buddy did the same thing about 15 years ago. I will get him to help me replicate their results.

Pics and tales will come – it may be a while.

-- If they can get you asking the wrong questions, they don't have to worry about the answers.

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jdh122

1104 posts in 3379 days


#15 posted 11-21-2019 08:18 PM

I think it should work – no different from steam bending really. I’ve steam-straightened a few chair parts for post-and-rung chairs without problems (and Curtis Buchanan, master Windsor chairmaker talks about it a few times in his videos on youtube). Two potential issues. Normally with steam you have to overbend because if will spring back a bit once taken off the form. And maple is a very poor steam-bending species. But both of these potential issues may not be much of a problem given how gentle the bend (or unbend) is.

-- Jeremy, in the Acadian forests

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