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Balsa wood is lightweight and beautiful. It is the material of choice to make toys, doll houses, toy furniture and for model projects. Balsa wood is available anywhere and is also very affordable. Where does balsa wood come from and its many amazing characteristics will be discussed in this guide.
Contrary to the belief that balsa wood is composite wood, this type of wood is actually from trees. Balsa trees grow naturally in the forests of Central and South America.
However, the small country of Ecuador on the western coast of South America is where model aircraft-grade balsa is harvested.
Balsa needs a warm climate and a lot of rainfall to grow. This is why the trees with the best strands of balsa are found on the high ground between tropical rivers.
The scientific name for balsa wood is Ochroma Lagopus. The word balsa is Spanish which translates to the raft. Balsa is light like a raft and has amazing floating qualities. It is also known as boya which means buoy in Ecuador.
Balsa tree growth
Balsa trees grow singly or in scattered groups. These trees grow very rapidly just like weed and in fact, balsa trees were initially known as weed. Balsa trees can reach a height of 60 to 90 feet tall and a diameter of 12 to 45 inches. If left to continue growing and unharvested, a balsa tree may grow to a diameter of 6 feet or more. However, very little usable lumber can be obtained from an old and large balsa tree.
Why balsa is light
The secret to balsa wood’s lightness can be observed using a microscope. The cells are big and very thin walled, therefore the ratio of solid matter to open space is very small. Only 40% of the volume of a piece of balsa is a solid substance.
The reason why it can stand tall and strong in the jungle is that it is actually filled with a lot of water, like a tire full of air. When balsa is processed, the lumber is placed in a kiln and is kept there for two weeks to remove all excess water. Drying will remove all fungi, bacteria, insect and other impurities in raw balsa.
Very light kiln-dried balsa wood
Finished balsa wood, like the ones in model airplane kits and boxes, is very light. Traditional balsa wood may only weigh 4 pounds per cubic feet but you can also find balsa which will weigh 24 pounds or more per cubic feet. Six pounds or less is considered “contest grade” and are used in premium model airplane kits and could be very hard to find.
Balsa for model airplane kits
Hobby shops dedicated to model airplane building have a large rack of balsa sheets, sticks, and blocks, all you can choose if you want to build model airplanes from scratch. When you select the pieces you want to buy keep their final use in mind.
You must choose lighter grades of balsa wood for lightly- stressed model parts like the nose blocks, wingtip blocks, fill-ins and more while heavier grades for important load-bearing parts like the spars, fuselage stringers and more.
Tools for cutting and shaping balsa wood
Balsa is easy to work with because it is light, soft and versatile. There is no need to use power tools. If you are just starting out in the model airplane hobby or new to using balsa wood, you only need a No. 1 knife with No. 11 blade for general cutting; No. 2 knife with No. 26 blade for carving; Razor saw to cut thick sizes of woo and a razor plane for shaping. Have replacement blades on hand in case your blade wears out or goes dull.
Aside from cutting tools, you will need an assortment sanding block. These are very important when working on model airplanes and other model construction. You can buy sanding blocks or make your own.
Be sure to stock up on 80 grit garnet sandpaper on the block during general construction. Most hardware stores have a rack of aluminum in various sizes and shapes. Lastly, you must glue sandpaper on different sizes of scrap plywood sticks and round dowels. These will be perfect for working in tight places and for shaping where a big sanding block cannot reach.
Balsa wood is one of the lightest woods and because of its unique properties; it is commonly used in making model projects like airplanes and doll houses. Balsa has many amazing qualities and is available in most craft stores.