Test for warped boards

[Wichman]

When I laid out the pieces for the Secretariette I had two sections of warped board and I wanted to try to flatten them, with a twist . 

After cutting I'm planning to heat the boards in Walnut oil, 275 degrees for two hours then press with weight until cooled ( about two days). I want to see if the oil bath will limit the checking and cracking that can happen with steam bending.

The test pieces, pattern by Charles Hand :

 

Edited January 5 by Wichman
additional information

[Wichman]

The two trivets cut out and first sanding. These are about eight inches in diameter and have a 3/8" warp. I'm hoping that all the frets will allow the trivets to flatten out easily.

 

[Scrappile]

Thanks for showing your experiment. I and anxious to see the outcome. I have received wood that cups and I have tried every method mentioned on youtube to flaten then.  I have never succeeded.  I have a beautiful piece of bloodwood that cupped.  I keep hanging on to it hoping I will find a remedy.

[Wichman]

Paul,

     I am hoping that cutting the frets out will help with the flattening process. I have used lightly warped boards in projects before, where I was using pinned mortise and tenon joints. I used clamps to hold the board in place, then installed the pin. The warp put pressure on the pin and prevented movement

Sometimes you can use "defects" to your advantage.

[Mike Crosa]

Looking forward to the results.

 

[rash_powder]

I have read in the past that cupping occurs from the stock not equal air exposure on both sides, so one side dries more than the other.  The solution was to get the hollow side wet as that side's wood fibers shrank more than the domed side; then lay the board wet side down to try and even the dryness out in the board.  

I have tried this with no success.  I have tried to moisten boards and then press them flat and let them dry with no success.  Whatever I am doing doesn't work out for me.  It just seems that with kiln dried lumber if its cupped or warped thats how it is.  

Best of luck and very excited to see the results of your test.  

 

How did you get the cuts so good with that much warp?  I would not have been able to keep them perpendicular to the face.  

[Wichman]

41 minutes ago, rash_powder said:

 

Best of luck and very excited to see the results of your test.  

 

How did you get the cuts so good with that much warp?  I would not have been able to keep them perpendicular to the face.  

I have read that with steam bending, the ligin in the wood has to "melt" and the quickly put in a form and clamped until the ligin cools and resets. Some hardwoods lose to many oils in the process and are prone to splits and checking. I have also read that some European countries use an oil based heat treatment on the wood. I figure that a flat form is still a form; so we'll see.

As for keeping the cuts perpendicular, just shear dumb luck.

 

[edward]

No fun working with warped wood, tried it and the board keeps jumping around, so  now I make sure the wood is straight.

[Wichman]

Yesterday I started the test. I used my countertop roaster oven and used walnut cooking oil. I had enough oil to just cover the 1/2" wood. I started at 200 degrees and let the temperature stabilize in the cooker. Next I raised the temperature 25 degrees every 15 minutes until I got it to 300 degrees, then let the wood "cook" for two hours. After the two hours were up I moved the trivets to the "press"; one cinder block on the bottom, one bamboo cutting board, then the trivets, another cutting board, and finally five cinder blocks stacked on top.

I'll give it five days to stabilize before I check for flatness.

[Fab4]

5 hours ago, Wichman said:

Yesterday I started the test. I used my countertop roaster oven and used walnut cooking oil. I had enough oil to just cover the 1/2" wood. I started at 200 degrees and let the temperature stabilize in the cooker. Next I raised the temperature 25 degrees every 15 minutes until I got it to 300 degrees, then let the wood "cook" for two hours. After the two hours were up I moved the trivets to the "press"; one cinder block on the bottom, one bamboo cutting board, then the trivets, another cutting board, and finally five cinder blocks stacked on top.

I'll give it five days to stabilize before I check for flatness.

Hey Wich:
You forgot the gravy... Good Luck!!!
Fab4

[Wichman]

Well the test is complete... and is a complete failure. When I first pulled the trivets out of the "press" they were completely flat, but within minutes they returned to the original warped state.  

They are still perfectly good trivets and at 7/16" thickness they should protect the surface underneath from hot pans.

[jerry walters]

Sorry it didn't work out Whichita.  But this is how we advance and I applaud you for this.  If at first you don't succeed, try, try again.

Jerry

[rash_powder]

I have a large sign I made myself several years ago but never hung.  It was leaning against a bedroom wall and warped; so I put it in the bathroom to rehydrate.  

One shower and it straightened out, so I left it in there for a few days.  A good, gentle steaming fixed it.  

Might work for your project, or other peoples.  

[Fab4]

3 hours ago, rash_powder said:

I have a large sign I made myself several years ago but never hung.  It was leaning against a bedroom wall and warped; so I put it in the bathroom to rehydrate.  

One shower and it straightened out, so I left it in there for a few days.  A good, gentle steaming fixed it.  

Might work for your project, or other peoples.  

Hi Mathew: If I was to walk into the bathroom with a slab of wood and turn the shower on, my wife would
get me locked up into an asylum without giving me a chance to explain...
Glad it worked out for you
Fab4

Edited January 22 by Fab4
ADDED TEXT

[Garyrenee]

You’re fighting against nature. Wood breathes like skin and every wood spiecies has its own characteristics. There is a litany of information available as you are well aware of. Grain direction is key but not definitive. Even if all the stars are aligned and you’ve done everything correctly there is still a margin of luck involved. Your tenacity should be applauded but in the end you might still be peeing into the wind. I wish you luck on this journey. The pleasure and pitfalls of working with wood.