The use of weathervanes, or wind vanes, goes back to early Mesopotamia. Writings unearthed in that area dated from 3,500 years ago mention a device used to determine the direction of the wind. Now we have far more sophisticated ways of predicting shifts in weather, but the weathervane is still a popular and useful decoration for many homes.
Sketch a equilateral triangle with four-inch sides on the balsa or luan for the head of your weathervane's arrow.
Sketch a trapezoid with the shortest side being 3 inches and the longest 5 inches for the tail of the arrow.
Using the scroll saw, cut out the shapes you just drew.
Sand the edges of the balsa shapes with the sandpaper. Sand the triangle on its flat sides as well to reduce its width slightly.
Using the scroll saw, cut a slit ½ inch deep into each end of the square dowel. Make it wide enough to insert wood shapes.
Drill a hole in the centre of the square dowel. The hole should be slightly larger than your 3D nail, but not large enough for the head of the nail to slip through.
Glue the shapes into the slits in the wooden dowel. Allow to dry.
Paint or stain and varnish the weathervane to seal the wood for outdoor use. Be sure the pivot hole stays clear. If you want, you can also paint the 1-1/8-inch dowel (which will be used for mounting).
Put the washer on the end of the 1½-inch dowel and hammer the 3D nail through the hole in the arm of the weathervane into the end of the round dowel. Leave approximately 1/16 inch of clearance between the head of the nail and the top of the square dowel.
Mount your weathervane outside and enjoy.
The trick to balancing your weathervane properly is to have unequal area, but equal mass on either side of your pivot point. (That's why you sanded the triangle point of your arrow.) Your weathervane will point into the wind, showing you the direction the wind is coming from.