How to remove warpage without planing?

[Enrico Caruso]

Hi, this is my first post to this site. I seek advice on ways to remove warpage from some boards that I am hoping to re-purpose for a small cabinet that I am trying to build.

Here is the background: the wood is new unused 3/4" hard maple 2" wide tongue and grooved flooring that is left over from a replacement floor in my kitchen five years ago. The wood was stored in a loft of my carriage house since then. The boards are now non-flat bowed banana shaped, with the bow at about mid-length of the 6 foot long boards, and I would like to make then flat again without having the boards planned. I have no capability to plane them.

Can they be weighted at the bow crown and pressed back into a flat plane? Would crosswise kerf cuts with or without weights help flatten them? The boards will eventually be shortened into 25" long pieces to be glued together forming the top surface of the cabinet. Any other suggestions from the accumulated wealth of your experiences is sought.
Enrico

[Jesse Busenitz]

Enrico,

First off welcome to the Creek! You might be able to stack the boards with 3/4" spacers between each row with a heavy weight, and get a little warp out of it, but if you're just using 25" pieces you may just have to pick and choose around all the really warped pieces. How was the wood stacked in the loft? If it's seen extreme heat/humidity and was just strewn about wood will do wacky things on you. Others will probably have better advice, but I decided to throw my 2 cents in.... Jesse

[Dave Cullen]

Chances are slim that you'll be able to straighten them enough to use in a cabinet. Weights don't work, the boards will just spring back. Someone here will probably suggest wetting one side and putting them in the sun to "pull" the fibers straight, but I've never had much luck with that.

[scott vroom]

Enrico, what are the final dimensions of the cabinet top? How will the top be attached to the cabinet? What type of cabinet?

No one can answer your question until you've cut the 6' boards into 25" lengths and measure the bow of the shorter pieces. Pulling minor bow out of a small top may be possible if you're attaching the panel to a similar footprint cabinet base.

How about you get some more info and come back.

[ryan paulsen]

Could you just tack/glue them flat to a substrate such as plywood?

[J.R. Rutter]

Maybe do double thickness by gluing opposite bows together? Unless they have uneven moisture balance (one face drier than the other face) I don't really see them ever being flat. But if they were stored spread out on a solid floor, then maybe they could be salvaged by flipping them and letting them sit for another 5 years. Sort of kidding, but not really...

[Enrico Caruso]

Thanks for the suggestions.
Jesse-the wood pieces were lying flat on the wood floor without anything on top of them. The loft is dry, except for variable ambient humidity, and was unheated except for seasonal temp changes.

Scott-final dimensions of the top are 25"x18", which is the same size as the cabinet base except I plan to "frame" the top all around with a 1 1/2" hard maple frame with mitered corners and route a decorative edge on the frame.

Ryan-I might be able to use a plywood substate to glue or screw the boards against to pull the bow out, if the bow cannot be eliminate by other means.

JR-I cannot glue opposite bows as all pieces as bowed in the same direction and flooring boards have an up and a down side. I am currently flipping them but cannot wait another 5 years. I need to finish the cabinet before Christmas.

Enrico

[Allan Speers]

I've had some success with the following:

1: Soak each piece in hot water, or just wet them by hand.

2: Suspend them all with the bow on top, across some cement blocks or whatever.

3: Take a clothes iron (Or a hair dryer, I suppose) and heat them to the point of just starting to "brown" them. When a board is as hot as you can get it, on both sides, put a weight on top. try to get it to bend down JUST past straight. (it would probably be even better to rig some kind of clamping system for better accuracy, but I've never bothered.)

4: Do each one like this, and then let them cool & dry.

5: Don't expect miracles. Wood wants to go where wood wants to go. Let them sit for a few days, then mill them down to 5/8"

6: Don't expect miracles.

[Jerry Miner]

Enrico---

Before you go any farther on this project, you'd better re-think the way you plan to do the top.

If you put mitered trim around a solid wood top, the seasonal humidity changes will cause damage to your top---either the miters will pop open, or you'll get a split somewhere in the panel. A solid wood panel needs room to move with seasonal changes.

I don't know where this cabinet will live, but assuming a 20% difference in Relative Humidity from season-to-season, you can expect an 18" wide maple panel to change dimension by 1/4" or so. You need to plan for that.

Flattening your boards without tools will be challenging for sure. If you cut to rough length (like 1" over-size)--you might be able to pick your flattest boards and glue them up, then flatten the panel with a hand plane, or belt sander, or whatever you've got access to. (A local shop with a wide-belt sander could make pretty quick work of getting a fairly-flat panel very flat. Good luck.

[Enrico Caruso]

Jerry- On your advice, I am now re-thinking the top design. I would be better off making the boards wider, and routing the decorative edge directly on the the top boards w/o the frame that I had planed to use. Thank you.

Allen-I would be worried about wetting the boards for fear that they would warp more as water is added, and maybe not entirely dried; but I am willing to experiment with a sample to determine the effect your suggested method has.

Enrico

[Allan Speers]

Enrico, the water turns into steam when you heat the boards. You are effectively steam-bending them, though not nearly as effectively as if in a steam box.

You can do it with just heat, (it softens the lignen) but in my experience, the water helps.

[Phil Mueller]

Hi Enrico...welcome!
I would do as others have suggested above. Cut the boards into 26" lengths. You may be surprised that at the shorter length, how less bowed they may be. You will need 9 pieces. Pick the straightest ones and glue them up. See what you have. You could then sand any bow out, if needed.

[Warren Wilson]

Since this is flooring material, was it finished on one side only? I have never tried the strategies others have suggested here, but wood finished on one side only is predisposed to warp. Knowing the cause of the warping might suggest other solutions to the wiser heads here.

[David Ragan]

I tried the wetting and weighting and waiting option on walnut. Futility.

I took the advise given, and ripped them, reverse the direction of the resulting halves, and milled again, and then had happy boards. (Internally stressed, to be sure, but appeared to be happy--like most people.)

[Mike Hollingsworth]

Put the board on the lawn with the concave side down.