Warping

[laurieo]

Help !
Being new to working with wood I decided to build a dinning table with resin , what could go wrong !.
I made a router sledge and rails to level my slab .
The slab is 4inch thick brown oak it has been cut down and air dried for over 15 years .It has been on the garage floor raised on 4x2 battons for six months and never changed shape .
I levelled off one side and went back in the morning to turn it over and do other side but found it had warped about an 1 inch from the middle to the edges .
Is there a way to flatten it back to shape.
I intend to split the slab down the middle eventually, if I do this now would it it stop further warping.
Sorry for such a long post .

 

[MorrisWoodman12]

@laurieo there are lots of people on here with masses more knowledge than I possess but my two penny worth is:
First wood is wood and is 'live' however long ago it was felled and moves with the seasons and as humidity changes. May not be much but it always moves.
Second when you cut it or remove a surface you disturb the current stress patterns throughout the timber and, guess what, it moves to balance its stresses again.
If you're going to cut down the middle as you suggest I'd do that sooner. It won't stop any further movement but I think you'll waste less wood while flattening the planks.
I'm sure someone will comment soon with more targeted advice.
Have fun
Martin

 

[baldkev]

Hi,
Thats a part of the game with wood!
It's likely that the material you removed changed the tension within the slab, causing the movement. Often when joiners resize timber, they take a pass from one side, then the other, hoping to reduce the chance of movement.
Some pieces move, others dont, it can depend on where in the tree the slab was , i.e, if it was near a large branch, it would have been working to support all that weight so the fibres would be under tension.

If you want to maintain maximum thickness, cut it through the middle, reflatten and then edge joint the 2 pieces.

You can also add detail like this:

 

[baldkev]

@laurieo there are lots of people on here with masses more knowledge than I possess but my two penny worth is:
First wood is wood and is 'live' however long ago it was felled and moves with the seasons and as humidity changes. May not be much but it always moves.
Second when you cut it or remove a surface you disturb the current stress patterns throughout the timber and, guess what, it moves to balance its stresses again.
If you're going to cut down the middle as you suggest I'd do that sooner. It won't stop any further movement but I think you'll waste less wood while flattening the planks.
I'm sure someone will comment soon with more targeted advice.
Have fun
Martin

Ha, we must have been typing at the same time. Good answer Martin

 

[MorrisWoodman12]

You too @baldkev . Like the photo - I'll bear that technique in mind.
Well enough of the mutual appreciation society for now.