Abstract: A solidified water soluble wood preservative characterized by a solidified elongate body of a boron compound known as having beneficial effects as a wood preservative, in combination with copper oxide. The method of making the solidified water soluble wood preservative includes the following steps. Firstly, mixing powder-form copper oxide (CuO) and a powder-form boron compound known as having beneficial effects as a wood preservative to form a powder mixture. Secondly, heating the powder mixture at temperatures in excess of 700 degrees celsius until the powder mixture melts to form a homogeneous liquid mixture. Thirdly, forming the homogeneous liquid mixture into a body. Fourthly, annealing the body at temperatures of between 300 and 550 degrees celsius.