If you've ever walked with the lumber aisle in a big-box hardware shop and noticed boards that look like they've been "zippered" together, you've possibly wondered what is finger jointed wood and in case it's actually strong enough for your own home projects. To the untrained vision, these boards may look a bit such as a Frankenstein creation. Instead of one particular long, continuous item of timber, you see multiple shorter pieces joined together with interlocking "fingers. "
It's a common sight in the world of structure and woodworking, yet there's a great deal of confusion about whether these products is a cheap shortcut or even a genuine design marvel. Honestly, it's a bit associated with both, but mainly it's a clever way to make high-quality, straight lumber from trees that wouldn't otherwise produce long, clear boards.
The basic mechanics of the finger joint
At the simplest, finger jointed wood is a structural or decorative timber product produced by joining short pieces of wood together to generate a longer board. If you go through the ends where two pieces meet, you'll see a collection of complementary rectangular "fingers" or tooth. These are precision-cut with a machine, slathered in high strength glue, and then pressed together below immense pressure.
The reason each uses this zig-zag design instead of just a flat "butt joint" (where 2 flat ends meet) is all about area. Glue works best when it provides a lot of surface to grab onto. By reducing those fingers in to the wood, you're essentially quadrupling the region where the glue can bond. As soon as that glue cures, the joint is technically stronger compared to the wood itself. If you would be to try and break the board more than your knee, it would likely snap in the middle of a solid area before it actually failed in the joints.
Why do we even make wood by doing this?
You might become thinking, "Why move through everything trouble? Why not just use a solid board? " Properly, nature doesn't often play nice. Whenever a tree is harvested, it's hardly ever perfect. It has knots, cracks, pitch pouches, and various other problems that make it weak or unattractive.
Within the old days, in case a long panel had a massive knot in the middle, you'd possibly have to use it as-is (and hope it didn't warp) or toss the whole thing directly into the scrap stack. Finger jointing changes the game. Producers can take a board, cut out the nasty knot and cracks, and then "re-assemble" the clean, clear areas back into the long, straight table.
This is an enormous gain for sustainability. We're getting far more workable lumber from every solitary tree. Plus, this allows for the particular creation of extremely long boards—20 foot or more—that will be nearly impossible (and wildly expensive) to find inside a strong piece of timber.
The magic formula advantage: Stability
Here's something most people don't realize: finger jointed wood is often much straighter and more steady than solid wood. Wood is the natural material that loves to shift. It twists, bows, and cups based on the humidity and temperature.
When a person have an extended, strong board, the materials runs in a single direction. If that feed wants to twist, the whole board twists. But along with finger jointed wood, you're taking a look at the composite of several different shorter pieces. Each piece has its own grain design and its own "intentions" for shifting. As they are all glued together, they tend to cancel every other out. When one segment wants to bow left, the following segment might want to bow right. The result is a board that will stays incredibly straight over time.
This is why you'll see it used so often for things such as: * Door and window trim * Baseboards * Crown molding * Wall studs (in particular engineered applications)
Is it mainly because strong as solid wood?
This is the million-dollar question. If you're building a deck or a load-bearing wall, you would like to know if these joints are going to hold up.
In terms of vertical compression—meaning weight pushing upon the board—finger jointed lumber is fundamentally equal to solid wood. That's the reason why you'll often find finger jointed studs used in residential framing. They may be straight, easy to use, and they can carry the weight of the roof great.
However, when it comes to "bending strength" or tension, there is the slight difference. As the glue joint itself is incredibly solid, the board's overall integrity depends on the quality of the manufacturing. For most household applications—like your trim or non-structural framing—it's more than sufficiently strong. But for heavy-duty structural beams, you'd usually shift up to something similar to Glulam (glued laminated timber), which is a different beast entirely.
The aesthetic trade-off
Let's talk about the elephant in the room: this doesn't always look solid. If you're planning on staining your wood to show away the natural materials, finger jointed wood probably isn't your first choice. The particular "zipper" joints are very visible, and since the pieces arrive from different parts of a tree (or even different trees), the color and feed won't match up. It ends upward looking like the patchwork quilt associated with wood.
Due to this, finger jointed wood is almost usually intended to be painted . Actually, if you go to the store and buy "primed" trim or even molding, there is a 99% possibility it's finger jointed wood underneath that white primer. Once it's painted, you'll never know all those joints are generally there. It looks like a flawless, high quality piece of solid wood, but in a fraction of the particular cost.
Working with finger jointed lumber
When you're a DIYer, working with this particular stuff is pretty straightforward, but there are a several tips to bear in mind.
Reducing and Sanding
You can reduce finger jointed wood exactly like you'd cut every other board. Your miter saw or table saw won't understand the difference. However, when you're sanding, be a little careful across the joints. Given that the pieces may have slightly different densities, you could occasionally get the tiny bit of unevenness if you're too aggressive having a power sander.
Nailing
One of the best things regarding finger jointed trim is that it's generally made from "clear" wood (meaning no knots). This makes it a desire to nail. A person won't hit a hard knot that deflects your finish toenail and sends it flying out the particular side of the particular board. It requires nails cleanly and regularly.
Moisture plus Outdoors
This particular is a huge a single. Most finger jointed wood you find with the local store is meant for interior only use . The particular glue used is typically not rated for constant moisture. If you use standard finger jointed trim on the outside of your property, water can seep into those tiny joints, cause the wood to enlarge, and eventually direct to the joints failing or rotting.
Generally there is exterior-grade finger jointed wood available (usually handled or created using water-proof glue), but you have got to specifically look for it. If this doesn't say "exterior rated, " maintain it inside.
The Bottom Series
So, what's the verdict? Finger jointed wood is a smart, sustainable, plus cost-effective solution regarding anyone who requires straight, long-lasting wood and doesn't mind a bit of paint. It's the great way in order to get "clear" wood results without the particular "clear" wood cost tag.
Next time you're working on a project and you need 16-foot baseboards that will won't look such as a hockey stay in six months, don't be afraid of these little zig-zag joints. They're there to help, not hurt. It's just one associated with those clever executive tricks that makes contemporary building a good deal simpler on our billfolds and our forests.