Every time a new woodworking magazine shows up in my mailbox, I am dazzled by a wide array of projects and techniques that promise to take my woodworking skills to the next level. Yet there’s something missing in the usual lineup of woodworking articles: failure.
As woodworkers, we tend to learn from the successes of others, but we are left to learn from failures that are entirely our own. In the spirit of rectifying that imbalance, I present to you several of my own woodworking failures–where I went wrong, what resulted, and how I ultimately dealt with the problem.
Dovetails and Cracks
Dovetails are supposed to be shrinkage-safe joints. They allow both boards to expand and contract with the seasons, so they rarely have trouble with wood-movement.
On the top of this bookshelf, however, a dovetail joint ended up causing a big crack right in the middle of the top board. (Apologies for the grainy picture; I promise that the crack is clearly visible in person.) I was building this shelf in a hurry, and I had just enough boards to finish the job. When I first cut into the board that would become the top, I noticed that it was pretty wet, whereas the other boards were quite dry. Well, I plunged ahead, even when driving my chisel into the wood to clear the waste from the joints expelled water from the wood! I should have stopped.
Once I had the whole thing finished, installed, and loaded with books, I forgot about the top board being so wet–until one day I noticed that a wide crack had opened up in the top. Of course the top had dried out and shrunk, but because it was dovetailed to a much drier board, the shrinkage had nowhere to go, so the wood split at its weakest point.
The bookshelf is still as sturdy as ever, and the cracks are fully contained, but every time I look at that top (on the rare occasions that books aren’t piled on top of it), I am reminded of the cost of haste.
One of my first big woodworking projects was this Shaker-style writing table made from home-center pine. My tools were completely inadequate to the job, but somehow I got it done, and my wife used it as a desk for a number of years.
The fatal flaw was the joinery between the legs and the aprons. What were designed as drawbored mortise-and-tenon joints became pinned tongue-and-groove joints after I blew out the top end of nearly every mortise as I chopped it with a chisel. So between the open ends of each “mortise” and the drawbore holes on each side, there just wasn’t enough wood surrounding all those holes to support the stresses of a table leg. The legs weakened over several years (that’s my oldest daughter peeking into the lower corner of the picture–she’s now in second grade), and eventually the joints failed altogether.
I sadly discarded the legs and aprons, but I am keeping the top for now. Maybe one day I’ll build sturdier legs for it.
Living on the Gulf Coast, where we get enough annual rainfall to rival Seattle (no, really!), wood has a limited lifespan outdoors. A couple years ago, however, I built a gate for the dog’s yard that I hoped would last good, long time.
I carefully joined the pine 2X8s together with drawbored mortises and tenons. I used a piece of a cattle panel for a center panel, so the cats could get in and out easily. Then I painted the whole thing, hoping that the paint would prevent rotting for a few years.
As it happens, paint is just as good at keeping water in as it is at keeping it out. The paint couldn’t possibly seal the water out of the joints, and when the rainwater did get into the joints, it just stayed there, rotting the gate from the inside out.
I don’t even remember if I had glued the joints too. I probably didn’t, thinking that if the drawbore pins didn’t hold the joints together, glue wouldn’t either. Well, no glue was going to hold up to this kind of water damage anyway.
I first noticed the joints beginning to weaken over the winter, and I knew the gate was doomed. This spring, there was fungus growing on it. Finally this summer, the whole thing collapsed, and I was forced to build a replacement.
This time, I determined to keep everything as weather-proof as possible. I screwed together some treated lumber and then painted the whole thing.
It’s not fancy-schmancy joinery, but it it should last longer than the first gate did. I built a swing set for the kids using the same materials and methods, and it’s still standing strong after five years of heavy use.
What I Learned
I’ve learned two things from these failures:
- Materials must be adequate to their environment, and to each other. Combining wet wood and dry wood is a bad idea. So is exposing rot-susceptible material to the elements. And no wood finish is waterproof–not even paint.
- Joinery must be adequate to the material involved. Overloading a piece of wood with joints weakens the wood too much. And insisting on using joinery instead of appropriate hardware can actually compromise the integrity of the whole structure.
I expect that this is not the last time I will describe and analyze my failures on this blog, if only because no woodworking magazine you’ll ever read will run regular articles on failed furniture.
Now I’m not saying that woodworking magazines should run a regular “Failures” column or anything. Well, come to think of it, maybe that’s exactly what I’m suggesting. Readers could submit short descriptions of their most spectacular failures and how they dealt with them.
I would be a regular reader, and probably an occasional contributor too.
I think this is a good idea. One magazine I used to read frequently ASME’s “Mechanical Engineering” I believe ran a regular article that was about a failure and how the root cause was identified and fixed. It was often my favorite article in the magazine. I think this would be a great addition to the woodworking world, either in article or semi-regular blog post form.
That’s why one of my prefered blog is “the accidental woodworker”. Ralph shows every problem he is confronted to.
This is not to critisise, I am just trying to do some woodworking and his skills are way ahead of mine.
For outdor equiment we now have ‘lasure’ which is supposed to let humidity go out. Paul Sellers tells that window frames were “glued” with lead minium paint when he was Young. I think this product is no more available (toxicity).