Cut the dowels in half using the hacksaw so you have two dowels which measure 2 foot each. Smooth the ends of the dowels with the sandpaper. Splinters may cause injury or snag clothing.
Sand the wooden block. Measure 1 foot from the top and mark it with a pencil. Lay the wooden dowels horizontally on the board. There should be 36 dowels. This should leave 1 foot of board at the top of the washboard and dowels all the way to the bottom of the board.
Staple each dowel to the board at both ends. Ensure that the staples are properly embedded into the dowel to prevent snagging. If you don't have a staple gun, use small nails to secure the dowels to the board.
Coat the entire washboard with lacquer to preserve the wood. Allow the lacquer to dry before using the washboard.