Plywood comes in 4×8 sheets. I needed 2×11 sheets. I ripped the sheets lengthwise into 2 foot wide panels, then cut two of the panels into shorter lengths. To join them, I used what’s known as a scarf joint. A bevel is cut on the end of each sheet, then the bevels are overlapped and glued to make the joints.
This picture shows the panels stacked with a 1.5 inch overlap. I used a belt sander to sand the ends until, instead of a stair-step, I had a smooth ramp.
The bottom sheet is a scrap of 3/4 inch plywood. This made it easier to maintain the proper bevel at the end.
Here are the results after beveling:
You can see the lines between the individual plys in the plywood. With a perfect bevel, the lines would all be straight. The bendiness of the lines indicates that my bevels aren’t perfect, but they will hold a glue line and be strong enough within the hull.
This final image shows the gluing process. I did two panels at a time, with wax paper between layers so they didn’t stick to each other. I used Titebond III glue. Epoxy would be a better glue, but since this boat is not going to be in the water permanently, and since the outside of the hull will be fiberglassed, Titebond is a suitable glue for these joints.
I used a 2×6 on top to apply clamping pressure across the width of the joint. This image shows the first two panels being glued. You can see the bevels for the next panels behind the clamps.
The four foot ruler was used as a straight edge to make sure one edge of the scarfed panel is straight (the left edge in the picture). Having a straight edge accomplishes two things: It makes sure the scarfed edges are properly aligned, and it provides a straight edge as a reference when marking the offsets for cutting.
Leave a Reply