Dry the tree stump in a sheltered place for at least a month, then bring it indoors for approximately two weeks. If the stump has already been dried for that period of time or longer, bring it indoors for approximately two weeks.
Set the dried tree stump on a work surface. Strip off all of the bark using a mallet and a chisel. Some tree species has bark that comes off easier than others. Take your time and carefully remove the bark a small amount at a time until it is completely stripped.
Sand the stripped tree stump with a progression of coarse to fine-grit sandpaper until all surfaces of the stump are completely smooth. Always sand with the wood grain to avoid scratching the wood. Wipe off the surface of the stump with a tack cloth to clean off the sanding dust.
Place the stump on a clean work surface. Brush two to three coats of wood finish onto the sides of the stump and up to six coats onto the top and bottom. Allow the finish to dry at least four hours, or as directed on the finish container, between coats. Lightly sand the finish between coats with fine-grit sandpaper. Wipe off the dust with a tack cloth. Allow the final coat to dry for 48 hours before continuing with the project.
Turn the stump upside down on a work surface. Evenly space the casters around the perimeter of the bottom of the stump, approximately 1 inch in from the outside edges.
Drive the screws that were included with the casters through the mounting holes in the casters into the bottom of the stump with a screw gun. Turn the stump upright and roll it wherever you have a need for an ottoman or extra seat.