Wood-clad planters are made in four steps.
First, an aluminum planter box is fabricated to fit your size specifications. Then, metal plates are welded to the outside of the planter. Once the metal plates are welded, the planter is powder-coated. And finally, wood is attached to the planter with fasteners. The fasteners are not visible on the outside of the planter.
Please see the images below to see the finished product.