How to Cut Balsa Wood

Co-authored by Garrett Faust

Last Updated: December 19, 2024

Balsa wood is the softest wood you can buy for model and design building. It’s very easy to cut, so much so that you need to be very careful and patient so that you don’t break it while cutting out your designs. Trace your cuts onto the wood with a stencil or other utensils, then carefully cut them out with a craft or utility knife. With a little patience and practice, you’ll be able to cut out just about anything you can imagine from balsa wood!

Part 1

Part 1 of 2:

Marking Outlines on the Balsa Wood

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1
Place the pieces of balsa you want to cut on a flat work surface. Choose a work surface that you don’t mind making cut marks on when you cut through the balsa wood. A work bench or a scrap piece of plywood on top of a table are good choices. ^{[1]
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- You can get balsa wood strips at a hobby or craft store. They are typically sold in sheets intended for making models.
Tip: Balsa wood that is ¹ ⁄ ₈ – ¹ ⁄ ₄ in (0.32–0.64 cm) thick is a good thickness to start with if you are new to cutting balsa wood.
2
Use a stencil or template to draw a pattern on the wood if you have one. There are lots of templates online that you can use as stencils for your balsa wood. Find one that you want to use and print it out on stiff paper so it is easier to use. ^{[2]
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- If you don’t know what you want to make out of the balsa wood yet, here are some ideas: gliders, airplanes, boats, model houses, and even bridges.
- If you can’t find a premade stencil you like, then you can draw your own by hand or on the computer. Keep in mind that some pieces will need to intersect if you want to create a 3D model, so you will have to cut some slots to fit them together as well as the general shapes.
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3
Use a ruler or other utensil to draw your own lines if you don’t have a pattern. Geometry utensils like protractors, squares, and rulers will help you create straight, angled, and curved lines on the balsa wood if you just want to freehand a design instead of using a stencil. Purchase a geometry set that comes with a variety of utensils that you can use for this. ^{[3]
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- You can use the utensils to help you cut perfectly along the lines you draw with them. You can also use them to help you cut along the lines of a stencil once you draw it onto a piece of balsa wood.
- Remember to create notches and slots if you want to fit things together to build 3D models.
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Mark the lines with a fine-tipped pen or sharp pencil. Trace inside your stencils or along your other utensils carefully with a pen or pencil to mark your cut lines on the balsa wood. Go over the lines a second time if you need to in order to make them stand out clearly on the wood. ^{[4]
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- A pencil will allow you to erase your marks and start over if you make any mistakes. Only use a pen if you are very sure of yourself!

Part 2

Part 2 of 2:

Cutting Out the Outlines

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1
Hold the tip of a craft or utility knife at a 45-degree angle to the wood. Holding the blade of the knife at an angle will allow the blade to cut most effectively. Use a brand-new knife blade for the best results when cutting balsa wood. ^{[5]
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- You can get a craft knife at a hobby shop, craft store, or online. Alternatively, a standard retractable utility knife will also work.
2
Begin your cuts on a part of the line that crosses the grain of the wood. Always start on a part of the line that is perpendicular to the grain of the wood (or close to being perpendicular). Balsa wood is very delicate and it’s easy to break if you start by cutting with the grain. ^{[6]
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- You can make all the cuts that cross the grain first (either perpendicularly or at an angle), and save all the cuts that are more or less with the grain for the end.
3
Pass the knife along the lines without cutting through on the first pass. Don’t try to cut all the way through on the first pass. Just focus on following the lines you marked and apply very light pressure to make a shallow groove on the first pass.
- You can use a ruler or other straight edge to guide your knife along straight cuts. If you drew any lines with a curved utensil, like a protractor, you can also use that to help guide your cuts.
- Don't use a stencil to guide your cuts, as they generally aren't sturdy enough. Just use stencils for drawing the designs.
Tip: Try to make the first pass for your cuts no deeper than ¹ ⁄ ₃₂ in (0.079 cm).
4
End your cuts on a part of the line that runs parallel to the grain. Always try to finish your cuts where the lines are most parallel to the grain of the wood. Stop at the end of the line if there is no place where it becomes parallel to the grain. ^{[7]
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- If your lines are mostly straight, then start with all the cuts that are perpendicular to the grain, and join the cuts that are parallel to the grain with them after.
5
Keep passing your knife along the lines 2-5 more times until you cut through. Repeat the steps as many times as you need to until you have cut out the shapes from your balsa wood. This will be about 2-5 passes of the knife along the lines, depending on the thickness of the wood and how much pressure you are applying.
- Be patient when you are cutting balsa. It’s better to pass the knife over your lines more times using less pressure. If you get impatient and apply too much pressure, you can end up breaking the balsa.
6
Sand the edges of the pieces smooth with 60- or 80-grit sandpaper. Carefully sand the edges of each piece after you cut them out. This will help all the pieces fit together and look better when you assemble them for whatever you are building. ^{[8]
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- If you have pieces that are the exact same shape and size, you can stack them together and sand all the edges at once.