You might have heard that acacia wood is super popular to use around the home, especially for high-end pieces, but why is this the case? Why is acacia so popular? Is it really that strong?
Something you might be wondering is if acacia is a hardwood or a softwood, which is exactly what we are here to answer today, and a lot more. Let’s figure out if acacia wood is hard or soft, how strong it is, and how it stacks up to some other popular types of lumber.
Is Acacia a Hardwood or a Softwood?
Acacia is a hardwood, as it is a part of the angiosperm genus, and it is a deciduous tree. This means that the acacia tree is a flowering or fruit-bearing tree and that it loses its leaves during the colder seasons.
So, acacia is a hardwood, and not only is it a hardwood, but also one of the hardest hardwoods that can be found all throughout North America. Acacia wood is hard, dense, stiff, and quite strong overall.
Acacia Wood Strength
When it comes down to it, acacia wood is actually extremely strong. This is true on virtually every front, or in other words, based on every factor that we could possibly evaluate this on.
There are five different parameters that we are going to use to evaluate the strength of this wood, and these include compressive strength, bending strength, stiffness, hardness, and density.
We’re going to take a look at each of these five factors to see where acacia wood ranks, both in terms of its own strength and in comparison to some of the other most popular types of wood out there. Let’s get to it and take a look at exactly how strong this wood is.
Compressive Strength
Acacia wood has a compressive strength of 10,131.2 lbf per square inch (roughly 713 kg per square centimeter).
As you can see from the above figures, acacia wood is indeed very strong. We could compare this to other types of lumber, swamp mahogany for instance, which has a compressive strength of 8,540 lbf per square inch.
Another wood, eastern red cedar, has a compressive strength of 6,020 lbf per square inch (see a more detailed comparison of the two). Balsa has a compressive strength of 1,690 lbf per square inch. On the other hand, ebony has a higher compressive strength of 11,060 lbf per square inch.
If you are unsure of what the compressive strength of wood is, this is also known as the crushing strength. This measurement refers to how much weight a piece of wood can take parallel to the grain.
How much weight can a piece of wood hold before it buckles? A simple example of this would be a table leg. How much weight can you put on the surface of a table before the leg buckles?
Bending Strength
Acacia wood has a bending strength of 18,263 lbf per square inch.
For those of you who don’t know, the bending strength of wood is also known as the modulus of rupture. Unlike compressive strength, which refers to how much weight a piece of wood can take parallel to the grain, the modulus of rupture refers to how much of a load a piece of wood can take perpendicular to the grain. For example, if you hang a wooden peg horizontally on a wall, how much weight can you hang on the end of it before it snaps?
We could compare this to western red cedar, which has a bending strength of 7,500 lbf per square inch, or to balsa, which comes in at just 2,840 lbf per square inch. On the other hand, Gaboon ebony comes in at a whopping 22,390 lbf per square inch.
Stiffness
The modulus of elasticity, or stiffness, for acacia wood is 2,364,115 lbf per square inch (16.3 GPa).
This means that acacia wood is in fact very stiff and that it takes a whole lot of force to cause it to bend or sag in the middle when weight or force is applied. For instance, the stiffness of balsa is only 538,000 lbf per square inch.
Acacia is stiffer than most other types of wood that you will have access to. In fact, it’s stiffer than alder, maple, pine, spruce, and much more. However, one of the stiffer types of wood is Gaboon ebony, which comes in at 2,449,000 lbf per square inch.
In case you don’t know what the stiffness of wood refers to, this is also known as the modulus of elasticity. This refers to how much a piece of wood will bend in the middle when a load is placed perpendicular to its grain.
You could imagine yourself standing in the middle of a wooden board that is being supported on both sides, and seeing how much weight it takes for it to bend. How much weight can you put on the middle of a board before it starts to sag?
Hardness
Acacia wood has a Janka hardness rating of 2,300 lbf.
We then have the hardness of wood, which is generally measured on the Janka hardness scale. This measurement of wood simply refers to how hard the surface of a piece of wood is. This is a measure of its resistance to physical damage, especially denting and scratching.
For the record, a Janka hardness rating of 2,300 is very high. In fact, this is harder than the vast majority of both hardwoods and softwoods that can be found throughout North America. For instance, eastern red cedar has a Janka hardness rating of 900 lbf, balsa has a hardness rating of just 67 lbf, and Douglas fir has a hardness rating of 620 lbf. On the other hand, Gaboon ebony is a much harder type of wood, coming in at 3,080 lbf.
Density
Acacia wood has a density of 47.44 lbs per cubic foot (760 kg per cubic meter).
Just like with all of the other factors on the list today, acacia also ranks very highly in terms of density, or in other words, it is one of the heavier and denser woods that you will come across.
For a comparison, balsa comes in at just 9 lbs per cubic foot, Douglas fir at 32 lbs per cubic foot, and alder comes at 33.3 lbs per cubic foot. Then, we have something much heavier, such as Gaboon ebony, which comes in at 60 lbs per cubic foot.
For those of you who don’t know, the density of wood quite simply refers to how heavy it is in relation to a specific area or size. This is usually measured in either pound per cubic foot or kilogram per cubic meter.
Knowing how dense or heavy a piece of wood is is quite important, as it is a direct indication not only of durability but also of how easy that piece of wood will be to maneuver and work with.
Is Acacia Strong?
The bottom line here is that yes, acacia wood is very strong, and is in fact one of the strongest woods that you can use. It has a very high compressive strength and bending strength, the stiffness and hardness are very high, and the wood is super dense too.
You can consider acacia wood to be one of the strongest types of wood out there, and this is true according to all five of the main parameters that wood strength is based on.
Summary
At the end of the day, if you need really strong wood that can handle an incredible amount of force (both against and with the grain), and is very hard, heavy, and stiff, then acacia wood is a fantastic option to consider.