A good pipe requires a dry cob at least 2 inches thick. Field corn is the best source; sweet-corn cobs are too small. If the cob is not dry, keep it in an oven at 120 to 140F for 8 to 12 hours.
To make the bowl, cut a cross section from the cob 2 inches long. For the stem, use a short piece of bamboo and the plastic stem from an old pipe.
Hollow out the cob, leaving a wall and bottom 1/2 inch thick. Drill a hole for the bamboo 1/4 inch above the interior bottom. Taper the bamboo to fit tightly and glue it in with epoxy. File the outside of the bowl partly smooth and apply a thin coat of plaster of Paris. Finish with fine sandpaper, varnish lightly, and glue on the stem.