Customizing & making trailing edge balsa stock

Many plans for model aircraft require trailing edge stock specifically in the wings, as this component plays a crucial role in the overall aerodynamics and structural integrity of the model. It's a common item that many builders will frequently encounter, so as an enthusiastic scratch builder, I like to keep various sizes on hand to ensure I have the right material for any project that comes my way. However, I often find myself with just one size, which can be quite limiting. Over the years, I purchased someone’s extensive hobby collection and ended up with dozens of pairs of 1.5" trailing edge stock. I've been utilizing these for various projects over the years and still have plenty left in my workshop. Fortunately, the wood quality is excellent, making it easy to work with, and it holds up well under various conditions, which is essential for the longevity of my models.

Currently, I am in the process of constructing a Baby Buzzard, a classic aircraft model that requires 3/16" x 1" trailing edge stock for the wing. Although I have a couple of pieces that are close to the required dimensions, one is too hard and the other too soft, which creates a potential issue for achieving a balanced wing structure. To avoid any discrepancies that could affect flight performance, I won’t use them as they are. Instead, I decided to take a proactive approach and resize larger pieces of trailing edge stock to meet the correct specifications needed for the model.

If you find yourself in a situation where your wood isn't the perfect size, don't let it dictate your actions or limit your creativity. Instead, take charge of the materials at your disposal. You can even create trailing edge stock from regular sheet wood that is 1/4 or 3/8 inch thick, or by laminating multiple pieces together to achieve the desired thickness. This adaptability is one of the joys of working with wood, as it allows for greater flexibility in your building process.

Here's my starting point for resizing the stock.

First, I marked the wood to cut it an inch wide, ensuring that my measurements are precise to achieve the best results. Given the wood has a tapered cross-section, I had to support it on another tapered piece to make the top flat, which is crucial for ensuring a clean cut. This step is important because an uneven surface can lead to inaccuracies in the final dimensions.

Next, I placed a metal ruler on the marked line and cut straight down, holding the knife vertically to maintain a straight edge. When cutting through a thick piece of wood, it’s important to avoid attempting to do it all in one go. Instead, make several passes, cutting a little bit each time. It might take 4 or 5 passes to achieve a clean cut. Here’s how the trimmed piece compares to the original size, demonstrating the effectiveness of this method.

While it's the right width now, it’s still too thick. My plan calls for a thickness of 3/16", and this piece is about 5/16". Therefore, I will need to trim off 1/8" from the thick edge, while the thin edge seems to be acceptable as is.

I prefer not to start with the sanding block immediately, as that would require a significant amount of sanding and time. Instead, I'll use a hobby-sized planer, which is more efficient for this task.

It's wise to shave a bit off, check the thickness, shave some more, and repeat this process until you are close to the desired thickness. Stop shaving when it’s nearly at the target measurement, ensuring you don’t overdo it.

Now it's time to sand the piece down to perfection. I place the thin edge at the edge of the table, holding it securely with my less dominant hand while I begin sanding. You’ll notice it can be challenging to sand the other end because your hand is in the way, and flipping the stick around isn’t an option since the taper would cause the sanding block to hit the table awkwardly.

To overcome this, I place an extra piece of trailing edge stock at the edge of the table as if I’m going to sand it. Then, I turn the piece I’m working on around and place it on top of the extra piece, ensuring the top is flat. This allows for easier sanding without obstruction.

It’s advisable to have a piece of wood with the correct thickness, your target thickness, set on the table. Frequently compare the thick edge of your trailing edge stock to your measuring stick to avoid over-sanding. This careful monitoring is essential to achieving the right dimensions without compromising the integrity of the wood.

Here’s what the finished piece looks like next to the original. You can clearly see that, besides the reduced width, the taper angle has also changed significantly, enhancing its suitability for the application in my model.

Now I have the exact size needed for the plane I’m building, and I also have some oddly shaped sticks left over from the process.

These leftover pieces will be repurposed as reinforcement around landing gear blocks, next to bulkheads, and behind firewalls. They are also excellent for reinforcing wing bolt blocks. Whenever the plan calls for trailing edge stock, triangle stock, 1/4" sticks, or similar materials for corner reinforcement in the fuselage, the specific shape isn’t as critical. You can use some of this material creatively and save a bit of money for your next jug of fuel, making your building process more efficient and cost-effective.

One last point to consider: This method is not only effective for reducing large trailing edge stock but also for enlarging small trailing edge stock. You can laminate a strip of sheet wood to one face of a piece that's too thin, and then sand it to the correct taper. Alternatively, you can add a thick stick to the thick edge to widen it. Balsa wood is incredibly versatile, allowing you to join pieces together until they resemble what you're building. This adaptability is what makes scratch building such a rewarding and fulfilling hobby.