If you are planning to build something out of solid wood, then you have many different options at your disposal, with balsa being one of them. This is a fairly popular type of wood, mainly because it looks pretty decent and is very affordable too.
With that being said, many people do have concerns about how strong balsa is. This is exactly what we are here to address today, whether balsa is a hardwood or softwood, and how strong it is in general. Find out just how strong balsa wood is below.
Is Balsa a Hardwood or a Softwood?
Something that you might know about balsa is that it is actually extremely soft. However, just because a type of wood is soft does not make it a softwood. This is indeed the case here, as balsa is actually classified as a hardwood, the softest of all hardwoods.
In fact, this wood is also softer than most, if not all types of softwood. Balsa is a deciduous angiosperm, which means that it is a flowering tree, and therefore technically a type of hardwood. However, as you are about to find out, this does not necessarily mean that it is strong.
Balsa Wood Strength
There is really only one type of balsa wood, so this is what we are going to be looking at today. Now, what we can say is that balsa wood is not strong, and this is true on virtually all fronts. Balsa is extremely soft, and it’s not very strong in other ways either, as you are about to find out.
As mentioned above, this is one of the softest types of wood out there, and this is true as far as both softwoods and hardwoods are concerned. To determine just how strong balsa wood is, we are going to be taking a look at five main factors.
These five main factors include compressive strength, bending strength, stiffness, hardness, and density. All five of these factors are important to take into account when determining the overall strength of a piece of wood. Let’s figure out just how strong balsa actually is.
Compressive Strength
Below we have listed the compressive strength of balsa wood:
- 1,690 lbs per square inch (11.6 MPa)
Balsa wood features a much lower compressive strength than virtually all other types of softwood and hardwood out there including beech, poplar, spruce, pine, mahogany, ebony, maple, and so much more.
In case you don’t know what the compressive strength of wood is, this may also be referred to as the crushing strength. This measurement simply refers to how much weight a piece of wood can take parallel to the grain. As a simple example, imagine it being placed on a vertical table leg. How much weight can that vertical table leg hold before it snaps and buckles sideways?
Bending Strength
Below, we have listed the bending strength of balsa wood:
- 2,840 lbs per square inch (19.6 MPa)
This is an extremely low bending strength. It doesn’t take much to snap a piece of balsa wood. Balsa is much weaker than virtually all other types of hardwood and softwood out there. We could list dozens and dozens of different types of wood, all of which have a much higher bending strength than this material.
The bending strength of wood is also referred to as the modulus of rupture. Compressive strength is all about how much weight a piece of wood can take parallel to the grain, but bending strength is all about how much weight a piece of wood can take perpendicular to the grain. As an example, imagine hanging a piece of wood horizontally on a wall, like a peg. how much weight can you hang on at the end of that peg before it breaks?
Stiffness
Below, we have listed the stiffness of balsa wood:
- 538,000 lbs per square inch (3.71 GPa)
That number might seem really high, but in the grand scheme of things, it’s actually very low. Based on that number, it really doesn’t take much to bend a piece of balsa wood, and this means that it cannot handle much weight before it starts to bend or snap. This is much weaker than virtually all other types of hardwood and softwood out there.
The stiffness of wood is also known as the modulus of elasticity. This refers to how much a piece of wood will bend when a load is placed perpendicular to the grain in the center. In other words, here you could imagine yourself standing on the middle of a wooden board that is being supported underneath on both sides. How much weight do you have to place on that board in the center in order for it to start bending or sagging?
Hardness
The Janka hardness rating of balsa wood is 67 lbf.
This is the number one weakest type of word on this front. Balsa is extremely soft. It is very easy to scratch and dent this type of wood. It is much softer than any other type of hardwood or softwood out there. If you are looking for something durable that won’t scratch, balsa is not the right choice.
The hardness of wood refers to how hard the surface of it is, or to be specific, how resistant the surface of a piece of wood is to physical damage such as denting and scratching. This is generally measured on the Janka hardness scale.
Density
Below, we have listed the density or weight of balsa wood:
- 9 pounds per cubic foot (150 kilograms per cubic meter)
Sure, if you like wood that is very lightweight and easy to work with, then balsa makes for a good option. However, nine lbs per cubic foot is about as light as it gets, and this is much lighter than any type of hardwood or softwood out there.
The weight or density of wood refers to how heavy that piece of wood is in relation to a specific size or area. This is generally measured in either lbs per cubic foot or kilograms per cubic meter.
Is Balsa Strong?
In the grand scheme of things, no, balsa is not very strong at all. This is true on all fronts. This is one of the weakest types of wood that you could possibly use for any purpose, so you definitely want to take care. However, if you want something that looks decent and is cost-effective, it is something worth considering.
Summary
Balsa is a fine wood to consider if you need something that is very affordable and good-looking. Just don’t expect it to be very strong.