Timber: unfinished Oak. 80x5x2 cm (30" x 2" x 3/4").
8, timber screws
Wood glue (PVA).

The finished frame should have a 12.7 cm (5-in) square opening and stand 5 cm (2 in) high.

Cut the wood into 4 pieces—2 pieces should be 13x5x2 cm. (5" x 2" x 3/4") and 2 pieces should be 16.5x5x2 cm. (6-1/2" x 2" x 3/4").
Drill two holes on the 5cm (2")-face ends of each of the longer pieces (that's 4 holes total per long piece).
Screw the pieces together and secure with wood glue. Recess the screw heads.
To finish the frame, lightly sand the edges. The mold is now complete.

Follow instructions within the recipe posting for using the mold to contain the Banh Chung during preparation.