actually this is take four.
exit hole on top. Mistake. lots of uncombusted smoke
exit hole on bottom. Better, but still lots of smoke
pipe extention to inject smoke into the heart of fire. That worked, but the ducting I was using still leaked smoke.
Somehow, the thought of using an old paint can came to mind. I looked at my collection of paint and I found two that were bad. I took the old primer can with thick yogurt consistency. Plus there was only 1.5″ left.
I cleaned it out and drilled a 1/2″ hole in the bottom for the pipe. Notice the elbow to reduce the chance of stuff getting in there. Also the small hardware cloth cage to ensure a clear path to the pipe. The outside of the can is a 3/4″ wash with threads cut into it using the pipe thread cutter I got from Harbor Freight.
Here, you can kinda see the pipe extending down into the fire.
The results are pretty good, though not very much of it. Need to find a larger paint can. Somehow I remember the existence of 2.5 gallon containers.