last summer, i built an external smoke generator out of a 18" piece of 3" schedule 40 pipe. it worked well and all that but constantly having to screw the lid on and off was a real pain. it would get all tarred up and glue itself on and you had to clean it all the time. quite a mess to deal with. i thought up a better solution that you all might be interested in. i used two pieces of treated 2X8 bolted together with a 14 inch carriage bolt out the top as a handle. then i attached a silicone baking sheet that i bought on ebay for 5 bucks (including shipping!) with small brads. this is heavy enough to stay put in high winds and the silicone sheet seals the top of the smoke generator well and keeps the smoke going to the smoker like it should. no more mess to clean up. cleanup is a snap with some rubbing alcohol and a scotch brite. i only have to clean it about every third smoke.