making a banana

[billm]

So I bought a nice straight piece of softwood 2000x142x33 PAR and spent an hour or so putting a 20x20 rebate all along the length with my router.

Then I cut it in 1/2 lengthways to give me a piece 2000 x71 with a 20x20 rebate full length.

When I started out everything was straight. The leftover 2000x71x33 piece is still straight but my rebated piece is bent like a banana lengthways. I assume this is because the tension in the wood has been released due to the 20x20 rebate ?

So my two questions are :
1. could I have avoided it bending by cutting it differently ?
2. and is there an easy way to straighten the piece I have now to save me making another one ?

many thanks

 

[Alarm]

Err, cut in half then rebate.
An hour to do the first one?
Wow

 

[billm]

Err, cut in half then rebate.

I have been told that it would still have bent if I cut it in half first then rebated it

 

[big-all]

make no difference if wood is going to move it will move lol
its not a stock size so where did you get it from and what wood was it??
was it seasoned and for how long ??

 

[billm]

I got it from the rack in the local timber yard. They had loads of it along with all other sizes of timber. I don't know if it was seasoned but it was the same colour as the 50 or so other sizes of wood in the rack.

I spoke to a joiner earlier today and he said there's no way of cutting it to avoid it bending. If its going to bend it will do .. he suggested make sure I put more screws in it to keep it straight !

I just wondered f I had done anything wrong .. sounds like I didn't

 

[big-all]

was your planed timber stored in doors or out ??
wood normally moves when the moisture content changes

if it was damp when you chose the timber you can try chucking it on the grass overnight so the dew soaks in
this may do nothing but it may ease the bend
if it eases the bend dry off any surface moisture assemble quickly out off sunlight and in a cold area

for future reference store the timber for 3 or 4 weeks in the same conditions it will be used in to allow it to reach the correct moisture content so minimise movement

 

[billm]

Hi, the rack in the timber merchants is outdoors but covered, so its dry but plenty of air around it. I kept the wood in the house for 2 days after I got it but it was outside for a day before I worked on it.

A joiner I asked said I could wet it and try to straighten it but that it would bend again once it was dry. I'm not sure how seasoned the timber is, when I drilled fixing holes in it the drill bit came out a bit sappy. So they may not have had it long in the timber yard.

 

[big-all]

what exactly are you making and what size is the finished timber and which way is the timber curving[face' side 'both]??

 

[billm]

I'm making a glazing bar, the rebate is for a panel to sit in and be finished off with a quadrant.

here is a drawing


Uploaded with ImageShack.us[/img]

My original question was just to find out if I should have done it a different way but I don't think I could have that would have made any difference. its just using softwood that decided to bend once cut and weakened by the rebate .. I think

 

[big-all]

surprising that such a big section off planed timber has moved you wont get it straitening unless it want to lol

anyway you will always get the odd bit off movement on about 5to 7% off planed timber but less on larger sections