Things You'll Need
Spanish cedar veneer
Clear silicon caulk
Silicon weather stripping
Humidor beads (or other moisture-control substance)
Cigar humidors are designed to maintain a consistent temperature and humidity so that the tobacco in the cigars can stay moist and continue to age properly during storage. Humidors come in all shapes and sizes. The only requirement is that they can produce a decent seal against moisture escaping, since cigars should be maintained at 70% humidity and 68 to 70 degrees Fahrenheit. A free-standing or wall-mounted cabinet can be easily converted to a humidor.
Remove any shelves that are in the cabinet and any shelving hardware. Measure the interior dimension of your cabinet. You should cover nearly every surface with Spanish cedar if possible. Figure the total square inches of the interior of the cabinet to determine how much cedar veneer you will need.
Spray the veneer with distilled water until it is moist then let it soak up the water for five minutes. Spray it again then sit a dictionary or other heavy book on top of it for 20 minutes to flatten out any wrinkles in the veneer. Repeat this process for all the sheets of veneer you will need for your cabinet.
Dry fit your veneer into the cabinet. Look for where the shelving hardware needs to go and use the hole punch to make holes in the veneer for the hardware. Cut the veneer with the utility knife if a sheet is too large. If you are cutting with the grain it will split easily (though not always straightly) along the grain. If you are cutting against the grain, slowly score the cut using gentle pressure and repeat the scoring until you've cut through.
Spread a thin layer of glue on the inside of the cabinet. Start with one side, covering the entire side with glue. Starting in the corner, press the veneer to the side. You will have some time to wiggle it into place before the glue dries. Wedge the veneer tightly against the corner then place your next sheet of veneer tightly against the first. Repeat until the side is covered. Repeat this process to cover the other side, as well as the back, top, bottom and door.
Apply the veneer to any shelves you wish to reinstall using the same method. Once the glue is dry (usually after 24 hours, but read the specifications on your glue), reinstall the shelving hardware and replace the shelves in the cabinet.
Seal the corners with silicon caulk to prevent loss of humidity through the seams of the cabinet. Install the silicon weather stripping on the inside of the door. Cut each piece to the length of a side of the door and then remove the film to expose the sticky back and press it into place on the edge of the door.
Place the hygrometer in the humidor and saturate the humidor beads with distilled water. Let the humidor settle for several days before storing cigars in it. It may take some time for the cedar to equalize in humidity so keep checking the hygrometer and the humidor beads. Aim for 70% humidity. Once it will maintain 70% over 24 hours move your cigars into the humidor.