The vital instructions are contained within Michael's site (linked above).
The construction steps I followed:
•Sized the .jpg template file in MS Paint and Word so that it printed out at the scale I wanted. •Printed out several copies of the template. •Squared out the balsa blocks to the exterior lines of the template. •Glued a copy of the template top-and-bottom to the blocks. •Rough-cut the balsa blocks to be just larger than the template curve. •Freehand-sanded the block to fit the curve. I used a stationary belt sander and moved the pieces by hand. •Cut the thin aluminum sheet to squares. •Formed the aluminum into curves. (This is the second-hardest part.) •Drilled holes the right size and depth to insert the rubber ducks. •Epoxied the curved metal pieces to the balsa forms. I used packing tape and light clamps to hold them in place. (This was the hardest part. If I were doing it again I would first make some kind of a clamping jig first.) •Painted. •Gloated. -- A good lock will keep an honest man out.