Instructions

Getting started

Start this project with a 8" x 40" board that has been planed to 7/8" thick. Crosscut a 30" section of your board to make the ribs and stretchers. Reserve the offcut to make the sides later. With your tablesaw fence set at 7/8", rip the two stretchers. With the blade tilted to 18' from square, cut the angled top of each stretcher. After crosscutting the remaining stock to 20", adjust the fence to 1/2" and rip the five pieces for the ribs. Once cut, use a hand plane to cut a 1/16" chamfer on all the edges.

Side orders

Plane the 10" offcut to 1/2" thick to use for the sides. The finished appearance and strength of this project relies on accurately crafting the side pieces. Lay out the pattern on paper first, then stick it to the wood blank with peelable spray adhesive. Use a bandsaw to cut out the curved shapes, staying just outside the layout line.

Now sand the sides to their final size using a disc sander. Cut the notches for the ribs and stretchers on the bandsaw using the sequence illustrated. Cut the shelf to size now.

Assembly

Sand all the pieces before assembly. Using polyurethane glue, attach the stretchers first, then flip the tray over and position the ribs. A wrap of surgical tubing around each end will hold everything in place while the glue cures.

Strengthen each joint

While glue alone would probably be strong enough, I added brass pins to all the joints. These ensure the tray will stay together and add jewel-like details to the project. To install a pin in a joint, drill a 1/8" hole about 1 1/2" deep. Slather some glue on the end of the brass rod and insert it into one of the holes. Using a hacksaw, trim the rod off 1/16" above the surface. Once the glue has cured, grind the protruding rod flush with a random orbit sander.

Lasting finish

The bathtub is probably the harshest environment a wooden project will ever be exposed to, so seal it accordingly. Four coats of satin polyurethane create a barrier against moisture. Now it's just a matter of drawing the bath, closing the door, and slipping under the suds for a warm soak.