How To Choose The Right Lumber - We Know What We Are Buying - 2

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Of course, if you buy only a few boards, then it will not be difficult to examine and identify defective ones among them. But when you need a lot - a large bag or a stack? Then problems will arise. However, mostly of a psychological nature. After all, the buyer, meticulously examining each board, undoubtedly looks like a bore in the eyes of both sellers and others. I believe that it is better to be known as a bore than to get a notorious marriage for your hard-earned money. However, I do not impose my opinion on anyone.

Defects in lumber

Now directly about the flaws of the boards. The most common and inevitable defect of wood, and therefore of boards, is knots. Knots not only worsen the appearance of the boards, but also violate the uniformity of the structure, and often the integrity of the wood. They cause curvature of the fibers, annual layers, thereby making it difficult to process.

Knots, especially edge knots (Figure 9), oblong (Figure 10), stitched (Figure 11) and group knots (Figure 12), reduce the strength of the boards when stretched along the fibers and in bending.

The so-called "tobacco" knots are also very dangerous. These are rotten or rotten knots, in which the rotted wood is completely or partially replaced by a loose mass of rusty-brown or whitish color.

Another common board defect is the already mentioned cracks. It is clearer than clear: if logs with cracks are sawn, then they will certainly be in the boards. There are four main types of cracks in the boards: metic (Figure 13), frosty (Figure 14), shrinkage cracks (Figure 15) and flawless (Figure 16). All types of cracks in the logs, and even more in the boards, violate the integrity and reduce the strength, therefore, significantly shorten their service life. Watch out for cracks!

The next defect of the boards is warping. Warping is a change in the shape of the cross-section of a board when it dries or moistens. Along the length of the board, they can bend, acquiring an arched shape. This is longitudinal warpage (Figure 17).

But sometimes the board takes on a helical shape (Figure 18). This is wingedness. In common parlance, such boards are aptly called "propeller".

And, perhaps, the last flaw of the boards is the curl (Figure 19). This is a local curvature of annual layers due to the influence of knots or germination (germination is a dead part of wood and bark due to damage to the surface of the trunk). The curl occurs in the form of partially cut brace-shaped curved concentric contours formed by curved annual layers.

There are two types of curls: one-sided and through. Curl (especially through) reduces the strength of the wood in compression and tension along the grain and when bending.

All of the above defects are inherent in the timber.

This is probably all in a nutshell about what to avoid when buying lumber. No, I in no way urge you to use all the advice in a row in practice. However, when buying logs, beams or boards for a specific purpose, remember what flaws can prevent you from using them for their intended purpose. Pay special attention to them.

Alexander Nosov, shabashnik with many years of experience