I have built a slightly modified version of this cold smoke generator:
I have found that I cannot sustain a burn/smolder in this generator and am in need of some suggestions. I am using a brand new, 1 gallon paint can. I have made a venturi from a 12" piece of 1/2" steel with a 1x1/4" slot cut in the middle. I am using a 1/4" piece of soft copper for the "jet" inside the venturi. The venturi is located across the approximate center of the can about 5" up from the bottom. The holes in the can for the pipe have a fairly tight fit. I have two 1" holes drilled opposite one another at the bottom for fresh air. I am using a small (tomato paste) can with holes drilled around it for a burn pan. I supply the air for the venturi from an aquarium air pump that is labeled for 1200 cc/min. For fuel I am using commercially produced pellets made for smoking foods. I light the pellets with a propane torch. I allow the pellets to "free burn" to establish a good amount of burn. I smother the flame by putting the lid on the can. The smoldering pellets produce a good, thick smoke. I hook up the small compressor and a good smoke volume is produced. After about 5 minutes the smoke begins to thin out. After 15-20 minutes the smolder is out completely.
Leaving the lid partially open will sustain the burning of the fuel but allows too much smoke to escape and not enough into the venturi. Closing one of the vent holes does not appear to change the time until the burn is smothered.
I have tried the following modifications since:
Moving the 1/4" pipe in and out of the 1/2" pipe creates no appreciable change in the smoke volume or the time to "smother".
I have created an adapter to attach the air tube to my compressor thereby allowing me to change the volume of air through the venturi-no appreciable change noted.
All of the homemade cold smoke generators I have found lack a spec for one component or another...or do not work consistently like mine either. I have looked at the Smoke Daddy cold smoke generator and can only determine that the air pump is much bigger than mine-something I would have overcome when I created the air compressor adapter.
I would appreciate any comments or suggestions.