wood movement

Roger Pozzi

Member
Messages
75
Location
Mount Vernon, Ohio
I've been reading a lot about wood movement and considerations to keep in mind about it but,,,, I have questions.
Movement seems to be caused by varying moisture content in the wood itself. Moisture seems to be received through the end grain for the most part and expelled throughout. Am I right so far?
If I am right then, wouldn't a sealer or some sort of "building" finish eliminate this problem? If moisture has no way in, the movement would be stopped, IMO.
Can anyone help me wrap my head around this?
 
Moisture more easily is released through end grain, but wood takes on and releases moisture across its grain. Like Leo said, it is never totally contained. You don't have your location posted so it is hard to tell you what to plan for. A reasonable rule of thumb is 1/4" across one foot. As an example, a panel door that is 12" wide would have the panel centered in its opening and would be able to move 1/8" on either side of center. That said, different woods, different rates of movement, but generally, not substantially so.

Movement can be planned for in various ways. If it is a inset, then maybe a little more space allowed. If it is a door, rails and styles and a panel rather than a slab. And certainly, during the finishing process, attention to sealing the end grain.

Most important. Wood moves. Period. How much has lots of variables. It is important to begin with dry wood to allow whatever weird movement that will happen, happen and go from there. Every buy a 2x4 that was on the heavy side and leave it for a few weeks in a warm area to come back and find it has turned itself into a pretzel? And it was a whole lot lighter? You will know what I mean. That's why houses tend not to have flat walls. The wood it slapped up while it is still wet with the idea that nails or screws will keep in it place. Not over the long haul they won't.

So what are you planning on making?
 
I can't add anything to what's been said already, but even the way the wood is cut can affect movement. Quarter sawn will react differently then flat sawn wood of the same species and just planning on dealing with it is the successful way to build something. I'm quite surprised by the number of folks who do something, and then "seal it" with whatever. Can't be done, and don't let anyone convince you otherwise. That said, it often does make sense to make sure whatever finish you use is consistent across the piece. Finishing the top of a board and not the bottom can cause one side to react differently than the other....and you get warping, cupping, or some other malady.
 
Leo and Carol have pretty well answered your questions.

One other considerations is the changes in humidity wherever you live. Some areas don't change much seasonally, but others vary widely.

Another consideration is where the wood is located. If it's furniture, doors, or cabinetry in a year-round climate controlled home (winter heat; summer air conditioning) then seasonal changes will be slight, if at all. Outside storage, or non-climate controlled, can result in changes of a quarter inch or more per foot of width.

By the way, if you edit your personal profile here, you can add your location. It needn't be specific - just a general area, state, city, etc. Whatever you're comfortable with.
 
Thank you all for your input. It's not that I'm unfamiliar with the concept of wood movement. I've planned on movement ever since my 1st project: desk.jpg
I wanted to learn about raised panel construction at that time, and I did. There is a total of 12 raised panels on this desk including the contoured ones for the top. All assembled using space balls mostly to keep everything centered.
I just started thinking more about it since I'm now making a lot of keepsake/jewelry boxes and there is no allowance for movement on these and I have not had any problems over the past 3-4 years with the ones I've made.
Carol, I'm eleven miles from the geographical center of Ohio where temperatures and humidity are subject to change at any moment.
 
...I'm eleven miles from the geographical center of Ohio where temperatures and humidity are subject to change at any moment.

I'm about 125 NE of you, in Austintown.

Ever get over to Millersburg, Berlin, or Charm? We go to Berlin/Charm fairly often. Keim Lumber & Hardware in Charm is a really great place for tools, etc. A few miles up the road, there's Lehman's Hardware in Kidron - a really interesting 'Amish" hardware store.
 
Small boxes probably are fine with little to no attention paid to wood movement. You would have learned plenty building that desk/ Your FIRST project? Man knows how to jump into the pool at the deep end. Good on you.
 
Living where I do, I don't have to worry too much about wood movement. The humidity doesn't change much throughout the year. In the winter it may drop a bit but usually not long enough to effect the wood. We get our coldest temps when the humidity drops a just few points and the cold air flows down off the show fields up on Mauna Kea and Mauna Loa.. Brrrr!
 
I'm about 125 NE of you, in Austintown.

Ever get over to Millersburg, Berlin, or Charm? We go to Berlin/Charm fairly often. Keim Lumber & Hardware in Charm is a really great place for tools, etc. A few miles up the road, there's Lehman's Hardware in Kidron - a really interesting 'Amish" hardware store.

Keim Lumber is my go to store --FANTASTIC! You didn't mention Mrs. Yoder's Country Kitchen at Mt. Hope.:headbang:
 
Yeah Carol. I spent a lot of time on that desk but, it also was a learning experience that covered many aspects of woodworking giving me a good general knowledge to move on with.
 
Good question and an important issue. I wish Tod were still active here, he could discuss it well. When I was watching him build the door for my church, the engineering used was a thing of wonder. He built it in a way that will (no doubt - WILL) withstand moisture variations for a long time. Forever? Wouldn't surprise me. It is a factor and the masters know how to work with and even combat the effects of changing moisture.
 
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