Twist in a sized door panel.

[Guyforks]

Hi Folks.
I have a problem with a sycamore board that’s 580x350mm and 20mm thick. This started life as a solid 4/4 about 700mm wide board which was cupped. It’s been taken down to thickness and levelled by hand. It has 1 large and 2 smaller knotts in running diagonally across the board. The panel was raised by hand and has been French polished on one side the other side has not been touched.
Now the board has developed a twist or wind. It looks like the knotts have dried and shrunk as it’s the opposing corners that have risen.
I’ve moved the panel into my house from the workshop (Which has a dehumidifier (10 Deg and 47%)) and dampened along the back side of the panel running diagonally from low corner to low corner. This worked and the panel become flat for a time but before I had a chance to do anything with it, it went and twisted again.
Right Question!
If I dampen the panel again and get it flat is there anything I can put on the back side to prevent the twist coming back. I’m thinking varnish or shellac, or will the wind just keep coming back.
Thanks
Glynn.

 

[Chrispy]

Hi Glynn

I would take a guess and say that sealing the back with the same stuff thats on the front would be a good thing to do. if you do this once the panel is flat even better.

 

[ankledeep]

snip<<< has been French polished on one side the other side has not been touched.>>snip

That may be the problem, I was always told.... If you put a finish on one face you need a "balancing coat" on the other...

but I'll bow to those of greater experience....

 

[Racers]

Hi,

It will be because of the finish on one side only, I have a piece of Beech in my garage that has been varnished on one side, and it cups very badly in damp weather but gradually straightens out it the weather stays damp, because the damp slowly penatrates right through.


Pete

 

[Guyforks]

Hi folks
Thanks for the responses.
In the end I’ve dampened the corner that twisted in the most (Lots of water) and clamped it face down on my bench with 2 strips of white rubber under the ends and left it to dry in the shop for 3 days.
It hasn’t done a bad job it’s a lot better than it was.
G