Wood Warpage

Wood Warpage

I’m sure I am not the only one with the problem of wood warpage, but have never seen a letter or article dealing with this (I’ve only been a subscriber for two years). It seems like no matter what precautions I take — things still warp. I am, like many others, sharing my garage as a woodshop and an everything else area. Like most garages in the summer, when everything is closed up, it gets quite hot in there. Could this be my problem? I really take pains to glue and clamp everything correctly, using premium plywoods, particleboard, etc., but after a couple of weeks my product is warped. I made a real nice drill press table by laminating birch plywood and particleboard to 1-3/8″ total thickness by 16″ x 30″. It warped. Any suggestions? – John Lewandowski

Tim Inman:¬†Burn these letters into your woodworking mind: E.M.C. (Equilibrium Moisture Content) Wood is not “alive” nor does it “breathe,” but it does react with its environment in ways metal and glass do not. It does take on and give off moisture from the air — which some refer to as breathing. Wood will ALWAYS come to equilibrium with the moisture content in its environment, sooner or later. As the conditions around the wood change, so do the conditions within the wood. Equilibrium Moisture Content is the result.

When you roast the wood in your garage/shop — or try making icebergs out of it — the E.M.C. in the shop-stored wood is very different than the E.M.C. in the wood after it becomes a project — or lands in its new resting place in your home or your office. Once the wood is at equilibrium, it will be stable — whatever shape it has taken.

Do yourself, and the wood, a favor. Allow it some time to come to equilibrium before you begin to work it. Once you do begin to use your wood for a project, keep it stored in the same basic environment it will eventually “live” in. Finish will slow the changes, but finish will never stop the changes. Just as ice can crack a rock, moisture changes in wood can have tremendous force. You cannot clamp or glue wood into submission. If it wants to move — it will. Work with the force and be happier.

Chris Marshall:¬†Sounds like you have a very damp shop environment if your sheet materials are warping this much. Maybe you live in a humid state or the garage floor slab is wicking up an excessive amount of moisture for some reason. In a garage shop where the space is still being used to park cars, it’s pretty tough to de-humidify it with a big garage door opening and closing. Are there other eZine readers out there who have come up with creative solutions to keep stock drier, despite really soggy air? Please chime in.

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