“A guy who came to Fight Club for the first time, his ass was a wad of cookie dough. After a few weeks, he was carved out of wood.”Fight Club (1999)
Woodworking is one of the oldest skilled trades in human history. Along with stone, clay, and animal renderings, wood was one of the most important materials for developing homo erectus. Of course, they didn’t have the benefits of world trade and large-scale transportation back then, so most early human ancestors just used what was available. Today, we have access to any type of wood we please, delivered to our door.
Since we have that luxury, why don’t we learn a little more about what kinds of wood we have access to and how to use them? There are three main categories that most wood falls into- softwoods, hardwoods, and manufactured wood.
Let’s look at the most common wood first- softwoods. Softwoods come from coniferous trees (evergreen, cone-bearing tress). The most common softwood is pine; the most common pine is the Douglas fir. Chances are this is what you will find the most of in your local hardware store. Pine trees grow relatively quickly, so their lumber is readily available and cost efficient. Most framing work is done with pine wood. As the name implies, most (but not all) softwoods are softer than hardwoods.
You can tell if a wood is soft by pushing your fingernail into it. If you are able to score the wood this way, it is a softwood. This also means that softwoods are easier on your tools. Duller blades can still cut through softwood with relative ease. Staining is also much easier with softwoods.
You can also find softwoods that are pressure treated so they can be used outside. The process involves vacuum-sealing the wood to pull out as much moisture as possible, spraying it with a preservative chemical, and then increasing the air pressure to force the chemicals deeper into the wood. You can usually identify a pressure-treated piece of wood visually by its green hue and haptically by its slight feeling of dampness.
Next we’ll look at some hardwoods. Hardwoods come from deciduous trees (trees that shed their leaves annually). Some common hardwoods are cherry, mahogany, oak, and walnut. Hardwoods are used in the construction of furniture and other items that are seen/used often due to their extra durability. They are also more commonly used for items that will be exposed to the elements. Because hardwoods are generally more durable, they are also more expensive, especially in the United States where not as many hardwood trees grow naturally.
Hardwoods are often chosen for aesthetic reasons as well. They are generally darker with more prominent graining than softwoods. This also means that staining is less likely to take on hardwoods. Generally only a clear finish is applied to add some extra shine and protection. Being harder by nature, they can wear down tools much quicker than softwoods, and dull blades often leave unsightly burn marks. If you’re going to work with hardwood, your best bet is to sharpen your existing blades or purchase new ones.
Manufactured woods typically serve different purposes from both hardwoods and softwoods. The two most common manufactured woods are plywood and fiberboard.
Plywood is made by layering thin sheets of wood in opposing grain directions. The layers are then glued together and cut to size. Structurally there isn’t much difference between cheap and expensive plywood; the higher price usually just means it looks prettier. If aesthetics aren’t a concern, you can cheap out on plywood without any real worry.
Because of the way plywood is layered, it is less susceptible to warping and expansion/contraction, which are common problems with most softwoods. You can also buy edge-banding for plywood, which can be ironed onto the edges to hide the layering.
One drawback to plywood is its tendency to splinter when being cut against its grain. Fortunately, this can be mostly mitigated by putting a run of painter’s tape down the middle of your cut line before you start.
The other manufactured wood we’re going to talk about is fiberboard. Fiberboard is made of (surprise!) fibers of various woods, as well as small amounts of paraffin wax, various adhesives, and other chemicals.
It cuts very smoothly and rarely cracks or splinters. One important thing to note about fiberboard, however, is that it can release harmful particles (such as formaldehyde, carbon monoxide, and hydrogen-cyanide) when cut. You want to be in a VERY well ventilated area and you ALWAYS want to wear a mask when cutting it.
Fiberboard generally comes in three different varieties, distinguishable by how densely the fibers are packed.
Low-density fiberboard, also called particle board, is the cheapest and least durable. It is highly susceptible to expansion/contraction, and as such, is rarely used in outdoor products. Generally speaking, particle board is used when cost is a more important factor than anything else.
Medium-density fiberboard (MDF) is stronger than its low-density cousin and can often be used in place of plywood for interior projects. If you’ve ever put together shelving or a TV stand from certain big box furniture stores, you are probably familiar with MDF. It is commonly laminated with a veneer on the outward-facing side and left untouched around the rest.
High-density fiberboard, also called hardboard, is the final type of fiberboard. As you can guess, it is the strongest of the three and is highly resistant to cracking and splitting. Although the use of hardboard has declined recently in lieu of more environmentally-friendly material, it is still commonly used to make pegboard.
Most lumber, regardless of its source, is bound to have some defects. The most common is warping. This is especially true of 2 x 4’s. Most pieces longer than a few feet will have some degree of warping. There are many different kinds of warping, from bowing (end-to-end) to cupping (across the grain). You can easily check how bad warping is by closing one eye and looking down each surface one-by-one as if you were aiming a rifle.
Other common defects are checks, shakes, and wanes. Checks are surface cracks that form around the old tree’s growth rings. Shakes are similar to checks but are natural separations in the wood’s rings. Wanes are areas where wood appears to be “missing” from the complete cut. These usually occur on pieces that were close to the bark of the tree.
Finally, the last defect we’ll cover is knots. Knots are the remnants of dead branches and dormant buds. They are arguably the most obvious defect to identify. The size and tightness of a knot is indicative of how intrusive it will be. A loose knot is likely to pop right out of the wood while a tight knot probably won’t cause you much issue so long as you aren’t cutting too close to it. Unlike other defects, knots (and wanes to a lesser extent) can actually be a good thing aesthetically with the right designs.