(this is a copy of my post to Sci.agriculture.beekeeping for the benefit
of Bee-L members)
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Just a follow-up to the message floating about on bee-vacuums.
 
These are really easy to make and are COMPLETELY invaluable in catching
hard-to reach swarms or removing existing hives.
 
I've modified the design of another beekeeper to accept most any wet-vac
or other vacuum to hook up to the box.  The most important  thing with
bee-vacuums is that you need to regulate the pressure so it doesn't whip
the bees into the inside 'bee-catcher" box (which has sidewall vents
made of harware mesh and allows air to pass & suck up into the vacuum,
trapping the bees behind the mesh inside the box).  If they hit the
inside box too hard, they'll die.    It's a very depressing feeling to
find thousands of dead bees inside the vacuum so please pay close
attention to the amount of suction.  If you have too much, you'll feel
their bodies bump hard down the vacuum hose - just the right amount &
you can barely feel them fly down the hose.  All you need is just enough
suction to make it halfway annoying (to you & the bees) on trying to
vacuum them off their comb (or tree...etc).  Too much & they'll rip
right off their comb (& the rip the bees off nearby comb) but you'll
find them all dead inside the box.  Just the right amount lets a few try
to hang onto the inside top-edge of the hose for a second...before
getting sucked into the inside box.
 
 
Thinking of building your own?
 
If you catch swarms or wish to pull feral hives, you'll absolutely want
to buy or build a bee-vacuum (provided electricity is close by).
 
 
Here's the idea:
 
Inside box - rectangular shape box with a removable bottom (mine slides
on & off) and has hardware mesh on either side.  Cut a single 2" hole to
match up to a vacuum hose which is inserted through both the vacuum box
& this box.....i.e..direct connection to the outside vacuum hose.
 
Vacuum box: - holds the inside box which contain the bees.  You'll cut
two openings:  first for the outside hose to attach to the inside box
and second to attach to any vacuum device (I use a 2 hp wet-vac which I
removed off the top of a $30 vac from Wal-mart - this is removable and
you can insert a 2" hose from another wet-vac if you need more pressure
- ...any vacuum device which hook up to the 2" hole I've cut at the top.
 
     Inside this vacuum box, you'll need to brace the inside box to keep
it from being sucked up to the vacuum (I use a couple 1" wood blocks).
As well, you need about 1/2" to 1" around the two wire-mesh sides of the
inside box so air flow can get sucked out (leaving the bees contained).
 
The kicker is the regulation of the air-flow.....all you need to do is
cut a 2" or so hole on the top of the box (at least 6" away from the
vacuum) and use wire-mesh to keep nearby bees from entering.  To
regulate the pressure, cut a piece of plastic, tin, tape....anything and
mount it to a screw above the hole.  This way you can move the piece in
front of the hole in varying degrees and it'll cut off outside air from
entering as it forces more air to pull through the vacuum hose.
 
Any dimensions will work.  I've read of one beekeeper using a lunch boxe
to catch bees.  (Though I've rarely seen the opportunity to catch such a
small bunch of bees....nor would I want to).  During swarm season, you
might need several inside boxes.....when one gets full, just pull it out
of the vacuum box & insert another (tape the exposed hole on the full
box, or use a sqare piece of something which swivels open & closed
manually).
 
Mine cost around $140 with fine 1/2" pressboard flamed maple and
clear-coat.  If I used 1/2" plywood, I could have built the thing for
$20-$30 (plus another $30-$35 for the 2hp vacuum, if needed).  The
inside boxes can be constructed of any  most any sturdy material.
 
Other particulars:
 
Cardboard won't work (I've tried) as the force of suction from even a 1
hp motor will crumple the box into nothing.  1/2" wood is what I used
for the outside box and 1/8" for the inside boxes.  Plastic edge-guard
(normally used on drywall) is good material for the rails on the bottom
of the inside boxes,  so you could simply slide open the bottom of the
box & knock the bees out into a hive.  My outside box has a hinged top &
bottom so I can quickly remove the inside boxes.  Any method of removing
the inside box (& bees) is fine.
 
If I can ever find the time to draw up the design I'll post the
address here.  (or, perhaps I'll find the time to make a video)
 
This idea has saved me hundreds of stings and saved the lives of alot of
bees (I wouldn't pull feral hives without one).  If you've ever tried to
remove an existing feral hive without a bee-vacuum, I'm sure you've
sworn off ever doing it again.  Try it by vacuuming off the majority of
bees first - then remove the comb one by one & vacuum the bees off each
comb as you go.  With less bees in the air & on the ground you'll have
less of a chance at any unhappy bee-meeting.  Plus the bees seem to know
they're in trouble when you vacuum off most of their population - the
rest will likely remain extremely timid.  At the end of the day you'll
have more salvageable comb (put back into empty frames and tie with
cotton string or rubber-bands) cleaner honey (without 1000's of
bee-parts) and a bunch more live bees.
 
The idea behing the 'bee-vacuum' is exceptionally simple in design and
you'll have much more fun in retrieving swarms or hives.  Good luck.
 
Matthew Westall in Castle Rock, CO