"De-stressing" wood

[davidtu]

I'm working on a first project (details, see the project thread) and I just made my rought-cuts--most pieces are around 6-7" wide and 5-14" long. This is wenge and zebra wood, purchased from Woodcraft, so they not terribly rough to begin with (tho not jointed or planed).

My question: how long do I have to let these sit before I can proceed with the project (making a small box)? Is there any way of judging if they are stable in a short period (say, overnight... if there is no change? 1 day?)

I'm told I have to wait 2 days, but I want to check to see if based on the weather, the wood, the progress... something... can I proceed sooner? I'm under a deadline, which is why I may seem impatient. I'm not, I just don't have much time.

PS: note I am in Seattle, WA and the weather has been hot and dry, tho it is overcast today.

Thanks!

[kwgeorge]

Most of the time I have seen wood warp or change after cutting the wood was soft like Pine or Poplar. I have heard that it is a good practice to let the wood acclimate to the shop conditions before cutting and there are mixed opinions on how long this should be done or even if it is all that necessary. Sometimes you will run into some wood that has tension in it and this will become obvious as soon as you cut it. I have had a few Walnut boards warp right when ripped while most have not.

With that though you are asking a question in which you are rolling two potential problems with wood into one. So we need to separate them. What you’re asking about is acclimating the wood to your environment to prevent later changes. To understand why you may need to do this you need to understand what issue at hand is. When wood is dried the endgrain on either end of the board is sealed which slows down the moister loss from those points and this allows the wood to lose its moister at a more consistent rate throughout its length. When you crosscut the wood you are exposing endgrain and if your shop has a higher humidity than the moister content of the wood the wood will absorb the moister of the shop until it reaches equilibrium with it. If the wood is not completely dry which is to say that areas of the wood have a higher moister content than other area of the wood when the fresh endgrain is exposed it will start losing moister until it reaches equilibrium with your shop. Both of these conditions will cause changes in the wood that will translate into warps and cracks but normally don’t show up until much later in the projects life.

Tension in the wood can be due to a few reasons. I normally find that cheaper construction grade wood has a lot of tension in it most likely due to the faster drying process. If you crosscut this wood you will find small cracks throughout the piece as a result of the Kiln drying process. Another potential issue and one I seem to run into is in more figured areas of the wood where the grain changes direction or what not. In these areas the wood is under tension and when you cut the wood that tension causes almost an instant warp in the wood. Most of the time this will be noticeable while cutting the wood.

So now that you have the long version here is the shorter, with where you purchased the wood and the size that you have cut it too I would not worry about it. If the boards are strait and true after you cut them then go ahead and get on with your project.

Ken