Is Balsa Wood Strong?

Is Balsa Wood Strong?

How many of you remember building balsa wood model airplanes?  The excitement of bringing the kit home, opening it, looking at the picture of the fully assembled plan – great memories.  And those balsa wood airplanes with adjustable wings that would fly and do loops?  Great fun!

But, you’re not going to build a dining room table with balsa wood or a set of chairs for it.  Balsa wood is light.  Its cells are big, with thin walls, and the ratio of “stuff” to empty space is about as small as possible and still has substance.  Talk about having no density!

However, balsa wood does have some interesting qualities.  For instance, it is among the strongest wood for its weight, pound for pound stronger than some hardwoods like oak, and softwoods like pine.  In fact, balsa is considered a hardwood itself. 

Remember, though, that hardwood is determined by the type of seeds a tree produces and not the uses of a piece of wood.

What is Balsa Wood Tensile Strength?

We’ve already mentioned that balsa wood is one of the lightest woods.  However, it is used in structural applications due to its strength – and stiffness – to – weight ratio and is often used as sandwich panels in such instances as bridge decks and even ping pong paddles.

Imagine the wood we built model airplanes with being used as a sandwich panel in a bridge deck you just drove over.  A ping pong paddle is a bit easier to understand, but that lightness, strength, and stiffness, pound for pound, is what makes it useful.

How Much Weight Can Balsa Wood Support?

Balsa wood is the lightest and softest hardwood lumber.  It’s white to oatmeal in color and in thin sheets is easy to work with, requiring only simple tools like a box cutter or sharp knife.

But its strength and stiffness in a span is only 50% of Baltic pine.  On its own, balsa wood will not support great weight in a span.  As mentioned, though, its lightness makes it suitable in a sandwich between woods or other materials that have a higher tensile and compression strength. 

You are not going to use it for furniture, shelving, or anything that has some heft to it.  Model airplanes and sandwiching materials are its highest, best uses.

Where Does Balsa Grow?

Where Does Balsa Wood Grow?

Balsa, also called balsa tree, grows from southern Mexico to Bolivia.  Balsa trees can be easily found in the humid rainforests of Central and South America.

Ninety percent of all balsa comes from Ecuador.  It is not farmed; instead, it is harvested directly from the jungles.  It is a sustainable resource in that it enjoys a regrowth rate of 6 – 10 years.

What Is Balsa Wood Good For?

We all know its use for building model airplanes, and we’ve already mentioned its use as sandwich material in various applications from bridge decks to ping pong tables.  There are other uses, too:

  • In wind turbine blades
  • In packing materials
  • In insulation
  • In floatation devices ( in Spanish, balsa means raft or float)
  • In stuffing for mattresses, cushions, and pillows

As such, balsa has a high commercial value as a versatile, lightweight material with multiple applications.

It has no value, however, where strength and durability are required.  Alone it can not support great or even a little weight.  It is intolerant to heat and absorbs the most water of any wood.  It is also highly flammable.

Whittle away with it as you build your model airplanes.  But you are not likely to choose it for much of anything else in your woodworking shop.

Is Balsa Wood Expensive?

Balsa wood is going to be expensive when you go to the hobby shop.  A 3/16 inch sheet of balsa wood might run you $10 per square foot.  Compare this to a 10” wide piece of pine at $9.88 for a 6’ length.  For that size, you can see how expensive balsa wood can be.

It is a bit pricey with the limited uses to which a piece of balsa wood could be used.  When you factor in its limited strength and durability and the fact that it splits and cracks easily, you will want to use it sparingly where it will last the longest – again, think model airplanes.

Let the manufacturing industry use it as core sandwiched materials while you stay with what’s fun.

Balsa Wood vs Basswood

Balsa Wood vs Basswood

Basswood is another hobbyist’s wood also used in making model airplanes.  It’s a little denser than balsa wood, has a tighter grain, and is also a bit stronger than balsa.  It’s relatively inexpensive and makes a good wood for carvers.  It is harder to cut and sand than is balsa, though. 

Basswood comes in blocks, whereas balsa is primarily available to the hobbyist in thin sheets.  It is more durable than balsa and is less likely to warp or split.  Basswood’s higher density makes it less prone to moisture absorption, and that density is uniform throughout the wood.  This makes it especially suitable for carving.

Basswood will tend to bend more than balsa, though, over a span.  If you’re building a model bridge, for instance, a span of basswood would be more likely to sag than would a span of balsa.

As with so many other wood choices to make in your woodworking shop, it comes down to matching the right wood for the right project.  Model planes, rockets, bridges, etc., are balsa wood projects, while a carved piece would be a basswood project.

Ah, such a pleasant memory, carefully choosing how far back to move the wings of the model airplane and watching it soar across the room, making it do a loop before landing.  A trip to the hobby store for the next balsa model was so exciting.