Build an Under-Window Bookcase

When the bookshelf is thoroughly sanded and the holes have been filled and sanded, wipe down the entire unit with a clean, dry cloth. I also like to wipe it down with a couple of tack cloths, to get any loose sawdust off of the bookcase.

If you choose to stain the unit, apply a coat of stain, brushing with the grain, to all surfaces of the bookcase, following the instructions that come with the stain. After the required time, wipe off any excess.

If a second coat of stain is needed to achieve the desired color, apply it once the first coat has dried. When the stain is dry, wipe down the bookcase and apply a thin coat of polyurethane, again brushing with the grain.

When the first coat of polyurethane has dried, lightly sand all surfaces with 220-grit sandpaper. Then wipe down the entire bookshelf and apply a second light coat. Repeat the steps if a third coat is desired.

If paint is your chosen finish, apply a single coat of primer, brushing with the grain, as per the instructions on the can. Then, when the primer is dry, apply two individual coats of paint.