Here is the cold smoker I made:http://i422.photobucket.com/albums/pp30 ... IM3291.jpg
I used a can with a pull top so the aluminum fence cap would fit in without falling in. I drill four 1/4" holes just above the bottom and punched 7 smaller holes in the bottom of the can.
Drilled a hole in the fence cap to insert a section of 1/2" copper pipe, added a copper T and a two more sections of 1/2" copper to the T. I got some 3/16" copper tubing and inserted a section through a 1/2" plug and put in on the end of the shorter 1/2" tube and soldered every thing together except for the longer 1/2" pipe so I would clean it out.
At the bottom I have some of the red oak wood chips. I took a log and split it up into small sticks and droped in in the chipper. One 6" log makes over 5 gallons of wood chips by the way.
I connected a small aquarium pump to the small tube, filled up the can with chips and lit the chips though the bottom larger holes with a butane torch. Smokes for about an hour. You can keep filling up the can with chips if you want longer burns. If you don't want to make your own you can also buy them ready made from Smoke Daddy just do a google search.