Push 36 pine 24-by-3/4-by-1/4-inch wooden slats through a planer, one at a time, length-wise. The planer shaves the slats to guarantee the thickness of each slat is 3/4 inch.
Lay the 36 slats next to each other, length-wise, on your work bench. Use a straightedge to align the slats along their short edges evenly.
Apply yellow wood glue across the slats, using a paintbrush to apply the glue evenly in a thin coat.
Set a 32-by-24-inch thin canvas on the slats. Press one corner of the canvas to the end of the last slat and slowly press the canvas down over all 36 slats. Press out any air bubbles caught between the glue and the canvas. Allow the glue to set for two hours.
Turn the piece over so the canvas is on the bottom and the slats are exposed. Place fine-grit sandpaper on an electric sander. Sand the slats to an even, smooth surface.