Buck the Establishment: Wood Acclimation
As most of you know by now, I enjoy tilting at windmills , think back to my “Don’t Use Push Sticks or Pads” blog. (I hesitate to link to that post, but I stand by that post , and I love comments that call me a moron.) Established “rules” drive me nuts. And they find ways to, or give excuses for, slowing work. I’m up on a soapbox today about wood acclimation, that is, giving the lumber time to acclimate to your shop before you put it to use.
According to the rules, if you don’t allow your lumber time to get use to its new surroundings, you’ll experience warp and twist to an extreme magnitude. Bull.
Here’s my story. Last Friday we picked up lumber from a woodworker in Lebanon, Ohio, a town just north of the Popular Woodworking Magazine (PWM) shop by about 20 miles. I needed some 4/4 walnut.
We brought some walnut back to the shop and dropped off a portion. The remaining lumber was left covered from the elements in the back of my truck then moved another 20 miles east to my driveway where it sat overnight.
The next morning I drove to my shop (a modest three-mile trek), pulled the wood from the bed of the truck, milled and assembled enough material for two side panels of the chest then went about other chores while the glue dried. Out of the clamps, the panels lay flat. I worked on the bottom-to-sides dovetails. No movement. Before I completed the joinery work on the second panel, I stopped and milled the boards for the case bottom, of which the front edge was the newly purchased walnut mated to fully acclimated poplar. (I live life on the edge.)
The panels remained in the shop for the balance of the weekend while I worked on router-based inlay patterns for the upcoming class. There was no movement. Believe it or not, I was hoping that the panels would warp so I could show the class that all is not lost if this happens to your boards. But there was nothing.
Was I lucky? I think not. What I do think is this: First, the lumber was properly dried to begin with. If hardwood comes into your shop at 22 percent moisture, it’s going to take months before you’re able to use it. Don’t buy it. One of my biggest pet peeves is woodworkers who try to save money by using cheapo lumber on a project that they are willing to spend weeks (if not months) building , projects that will be around for generations to see and enjoy. Why cut corners with the wood? Buy quality and buy from a respected dealer. Second, if lumber is moved from a close proximity to where it will be worked, there is no severe change in the elements. Therefore, there is no need for acclimation. No excuses. Get to work.
Also, use proper milling procedures. As you peel off layers of the boards to bring the wood to square and flat, make sure you take equal amounts , as equal as you can get , off both faces. Mill everything off one face to expose areas of differing moisture content and you’re sure to bend the board. Technique is key.
There are certain instances where this so-called rule stands. Construction lumber purchased from a home store is pulled from the kiln with the moisture content anywhere from 20 – 25 percent. As you know, there have been many benches built in the PWM shop using construction lumber. Take construction lumber from rough to panel in a quick day and you’re asking for trouble. This lumber should be purchased well in advance of when you’ll cut into it and allowed to acclimate. In fact, if you can break down the rough stock into pieces that are oversized in length and width, the reduction in moisture is quicker.
The bottom line is to understand your lumber and how you intend to use it, and follow proper techniques. Sorry about this , you’ll have to think for yourself. Don’t follow some ill-conceived woodworking axiom that begins with the word “always” , as in “always let your wood acclimate to your shop.”
Did I touch a nerve? Let me hear your thoughts. Leave me a comment.
– Glen D. Huey
- Read “Why Wood Warps” from the Summer 2009 Woodworking Magazine, available here.
- Click here for information about Chester County Furniture at the Chester County Museum.