Trace a circle around the body of a calabash gourd with a tracing pencil where the neck begins to widen. Use a small saw to cut off the top of the gourd.
Remove any seeds or pulp left inside the neck of the gourd. Discard the rest of the body. If the gourd is fresh, leave it in the sun to dry out. This can take a few weeks.
Sand the inside of the gourd neck using coarse sandpaper. Sand the outside, removing any paint if the gourd was previously used in a decoration.
Drill a 1/4-inch hole into the end of the gourd. Do not cut into the wall of the gourd. Blow air into the hole to ensure you have a passage for air.
Cut grooves into the walls of the gourd a few inches deep with a craft knife. Make the grooves about 1/2 inch down.
Measure out a ring of cork board so it matches the perimeter of the inside of the gourd. Cut it so it's about 1/4 thick and goes as deep as the grooves you cut into the pipe. Wet your cut piece with a little water, twist into the spray paint can lid and let it dry for 24 hours.
Work the dried cork board into the pipe and hold it in place with acrylic glue. Cut off any excess and sand down with sandpaper.
Remove the stem from a cheap pipe. Cut the shank from the bowl with a saw and sand it down.
Attach the shank to the gourd by inserting the metal tube into both pieces. Glue it into place and blow in and out to make sure the air flows properly.
Sand down the bowl of the cheap pipe. Shape the bowl with the craft knife so it fits into the cork-filled end of your pipe. Drill a small hole in the bottom of the bowl.
Measure the perimeter of the bowl and cut a small piece of tin to ask as a rim. Wrap it around the bowl and nail it into place with a small hammer.
Remove the bottom of an aerosol can and clean it. Measure the opening of your pipe's bowl and cut a circle out of the metal to fit into the bowl. Solder it to the bowl using a butane gas soldering iron. Place the bowl inside the end of the gourd pipe.
Shape the plastic stem from the cheap pipe with a heat gun so it curves at the angle you want. When it dries, insert into the shank. Glue it in place and allow it time to dry before smoking your new pipe.