Developed jointly by Oliver Brooks and Albert Knight, this
device was detailed in the Spring 1998 edition of
Bee Improvement magazine. This
page has taken the text more or less verbatim, but I have redrawn the
Note- The diagram is a large file that may take some time to
load... So read the description first.
This thymol frame can be made up using parts from a spare
brood frame (DN1). The only extra bits being some thin plywood and a
piece of thin cloth material, such as linen.
A spare 22 mm top bar is cut to fit in, at the height to
suit using shallow foundation. This should be unwired drone foundation
so that drone larvae can be removed as a control measure against the
mites when Thymol is not in use, i.e. during a honey flow.
shown in the cut - away sketch below is the trough in its
working position. This is placed on the three pieces of side bar that
are glued and nailed to the mid bar inserted for shallow foundation. A
cover of wire mesh is provided on each side of the trough and these
are held in place by wire rods threaded through staples set in the
top bar and the bar above the frame of drone foundation. The wire mesh
holds the trough in place. The vapour from the crystals flows
downwards through the linen material and passes out through the wire
mesh into the brood box.
Dose: 8gms per week over 4 weeks. The frames should be
'warm' way, and the thymol frame should be at the rear of the brood
nest (furthest away from the entrance). To be effective the
evaporation rate should be such that most of the 8gms is evaporated
in a week. Obviously temperature plays an important role in the
evaporation rate, so reasonable temperatures must prevail when
Caution: Thymol is a powerful disinfectant and causes burns, is
harmful if swallowed, avoid contact with the skin and eyes, use gloves
and goggles, and after contact with the skin wash immediately with
plenty of water.
The wire mesh will need the propolis cleaning off
from time to time. (See comment at page bottom.)
The trough to hold Thymol crystals is made from two pieces of
thin ply nailed and glued to two wooden end pieces (using part of the
lugs cut from the top bar of the spare frame). Linen cloth (or very
fine plastic mesh) is stretched across the bottom of the trough and
glued to the sides..
The components required to make up this device are standard
a 22 mm wide topbar, two x 22 mm wide straight side
bars, two x bottom bars (B1),
a mid bar that is effectively
another topbar with the lugs cut off, two thin plywood strips
335 mm x 28 mm,
various pieces cut from 9 mm thick x 22 mm wide
timber (a spare side bar), a piece of shallow drone foundation,
Thin linen cloth or very fine nylon mesh filter material.
Albert has commented
"It is worth saying that when the frame is not in use the wire mesh
panels are detached and placed in a freezer for 24 hours to make the
propolis brittle, then the mesh can be cleared of propolis by a few
Originated... 20-25 Feb 2002