Anyone pushed oxalic acid fumes into a TBH? From the top or from the bottom?
Ahh - I see folks inserting electrical vaporizers into Lang entrances, so the fumes must rise. That plus some YouTube illustrations seem to indicate I can drill a 3/4" hole in my bottom board, mount a flange externally, screw in a 4" length of capped pipe and use that as a vaporizer chamber, heating with a propane torch. remove roof of hive and watch for vapors to start and to end. think I'll position this under the general area of the brood.