Whether you call it a craft or construction, wood projects are as diverse as their builders. But universal truth applies, especially to successful wood building. Your grand vision must be built on strong materials and stronger knowledge of them. This is especially true of wood’s 1600-plus species.
Building With Wood
Wood is puzzling. We cut down trees, and they are officially dead. However, wood continues to absorb and release moisture vapor as if it was still alive. In that sense, wood is interactive with the air’s surrounding environmental conditions.
Wood manufacturing is a great education in moisture content (MC) management. From the forest floor through to the processing plant, professionals carefully monitor changes in the woods MC. In fact, lumber drying mills must control the dry kilns relative humidity(RH) and temperature among other variables so it can deliver strong, stable wood products to hobbyists (among others). The moisture content mandate reaches all the way to your building supply dealer. The good ones understand how local weather, wood species and processing all affect the quality of the product you purchase for your wood project. Good wood is only as good as its moisture maintenance.
Moisture Content for Hobbyists
Successful wood projects depend on a hobbyist’s understanding of moisture content (MC): the percentage of water vapor held within the wood. As you saw, plane, sand and assemble wood, its MC levels change according to the relative humidity (RH) and temperature of the air surrounding it. When RH rises, wood expands as it absorbs water vapors from the air. When RH falls, wood shrinks as it releases water vapors from within.
Wood moisture control is simple math. Let’s say your indoor RH level is 45% with the temperature at 70 degrees F. Let’s say your purchased wood stands at a healthy moisture content of 8.5%. If your RH increases from 45 to 50%, your wood moisture content rises from 8.5% to 9.2%. If your RH decreases from 45% to 40%, your wood’s MC falls from 8.5% to 7.7%.
The moisture content of the wood can easily complicate your project. “It’s a little muggy out today…” causes enough change in MC to make your wood harder to cut, glue, machine and finish. That’s because moisture content literally can change wood’s dimensions; even one odd-sized piece (altered by changes due to moisture content) can ruin the rest of your wood project.
Fear Not, Measure Wood MC
Technology has delivered convenient and precise moisture content meters to wood hobbyists. Wagner Meters features non-damaging hand-held analog and digital meters for both the hobbyist and the professional that you can pack on your tool belt. Just run the meter along any surface of your wood project and you can read the MC instantly. You can measure the same piece multiple times as the RH changes during your wood construction project. Wagner Meters even has a model that will allow for the easy storage of MC data for quality control documentation purposes.
The proper moisture content of your wood will be the strength of a wood project well-built. So be sure you’ve got the tools to build your project like a pro.