Wood Movement.

[wizer]

Hello

A couple of weeks ago I Re-sawed, planed and thicknessed some Ash for my stool legs. I left it only about 1mm thicker than needed. What with one thing and another I haven't had a chance to get back in the workshop til today. I found that one board had twisted and one had cupped. The timber had been in my workshop for a few weeks before being prepared. I will have to use fresh timber now as these boards will be too thin once re-planed.

Question is:

How do I prevent this in the future? Should I bring the timber in the house when not being worked on? Or is it best practise to complete the whole project immediately after re-saw, plane and thickness?

TIA

 

[Wanlock Dod]

WiZeR,

I tend to take all of the parts back into the house in between sessions (even just overnight) and everything so far has stayed nice and straight. I currently manage to keep quite a good dry wood supply under the spare bed

Cheers,

Dod

 

[OPJ]

I agree. Although, I seem to have gotten away with it looking at something I have just finished making... :wink: Then again, the oak I used was bought in October, stacked indoors and not taken outside until last month.

 

[PowerTool]

Same as Dod - I keep dry timber in the house,normally for a week or two before use,and only take it outside when working it.

Andrew

 

[les chicken]

WiZer

How are things especially the baby and your good lady wife not to mention the dogs. Helen is still waiting for a picture of the little one.

When I resaw timber I tend to stick it and leave for a few days to let the stress come out of the timber. Then I will plane it flat and square stick it and again leave it to stress relieve.

Then i will plane it to size, but do not pile it on top of one another, always stick it to keep air circulating on all of the sides, to prevent one side drying faster than the other.

Les

 

[Paul Chapman]

When you plane and thickness, do you take equal amounts from each side? If you take a lot more from one side than the other, it can result in unequal stresses and the wood to warp and twist.

Cheers :wink:

Paul

 

[Digit]

The centre of a piece of timber will always be wetter that the outside, so if you plane just one side that side is now wetter than the opposite side. Always, where pos, plane both sides equally, if it was straight before it should then remain straight.
Also, never lay your freshly planed piece flat on the bench or similar surface for any length of time as this will also result in in uneven drying and movement. I know!

Roy.

 

[wizer]

Big D'oh for me then!

I did take quite a bit off one side. This was mainly due to dodgy re-sawing :roll: I need to practise that too.

Our house tends to be quite hot most of the time (Mediterraneans at heart). Should I keep it in an unheated room? or in the warmest part of the house?

I'm learning, I am.

Thankyou

 

[Digit]

Purely personal viewpoint from me, others may have found different results, but I keep the stuff warm.

Roy.

 

[wizer]

Right so, luckily I over ordered on the Ash.

I just cut off 600mm and ripped down the middle at 150mm. It's current thickness is 50mm but needs to be resawed in half. I surfaced one face and then stickered it in my spare room/office. This room is unheated but quite warm due to all the IT equipment jammed in there. How long should I leave it here? Should I move it into a heated room after a period or should it be ok where it is?

 

[Wanlock Dod]

Wizer,

I think that in an ideal situation you should leave your timber indoors at least until it has come to equilibrium with its environment (which will take rather longer for thicker timber). Probably the simplest way of assessing this is to wait until it reaches a constant weight, although big bits could be hard to weigh (it's OK for bowl blanks though )

A moisture meter may help a bit but I think that most only measure near the surface of the wood (in this case wait until constant moisture content).

Cheers,

Dod

 

[Digit]

The best advise I can give is always have a supply of wood to hand that is dry. There's no fluff under our bed, but there's lot of timber!

Roy.

 

[Matt_S]

Do pro. cabinet makers have beds nearly touching the ceiling, very warm workshops or just hope for the best?

 

[bob_c]

I think the best advice ive had is to avoid any sudden dramatic changes in temp and humidity.Try and find out how the wood was kept before you bought it and dont immediately stick it into a hot centrally heated room if its been stored in an open shed by the suppliers.The same applies in reverse.I agree with what others have said also like leaving it to settle after you have resawn it ,etc..Also try and watch the grain when your resawing as if grain is twisted to start with its bound to move after being resawn.Whenever i resaw large thicknesses i always try and make the grain as near to quarter sawn as possible.

 

[Ian]

I usually buy the timber and store it in the workshop for a few weeks (kiln dried) then resaw or plane both sides equally leaving about 6mm extra thickness
It then is placed in under our bed away from the radiator and either on edge or stickered for about 2 weeks

then I bring down to final dimensions take equal of each side and when I have finished for the day the project comes in again.

Ian

 

[wizer]

Thanks all. I'll take a gamble and leave it for just one week before I re-saw it, then leave it another week before I finish the project. Can't wait any longer than that!

It would be very easy to run a radiator into the workshop so I will look into that. It'd benefit us anyway as our bedroom is above the workshop and it's the coldest room in the house.

 

[wizer]

seeing as we're on the subject. How is timber intended for outdoor use treated? It is currently stickered and covered outside. I guess this can stay where it is until used?

 

[Digit]

It's no win subject in my experience. Here where I live, close to the coast, the weather forecasts are replaced by looking out of the window, rain one minute very hot the next.
I leave the timber outside but I know that it is going to move and try to make allowance in my construction methods.

Roy.

 

[Wanlock Dod]

WiZeR,

As far as timber for outside use is concenred I woudl follow the same philosophy that I have for interior wood. Store the wood in its intended resting environment at least until it has reached equilibrium with it (ignoring the fact that the environmental conditions will vary). If I was going to use the stuff outside then I'd keep it outside, although I'd be tempted to keep the rain off it if I could.

Cheers,

Dod