Blue Ribbon Beetle Trapping Bottom Board

Disclaimer:

The original plans, drawings, and words can be found in American Bee Journal (Volume 158 No. 5) p. 545-552 by Luke Goembel. Every now and then, I have edited steps, words, and phrases for conciseness or clarity. I have also edited pictures to zoom in on particular subjects. However, with those exceptions this is a copy of the original work by Luke Goembel. At the time of writing this, I am not aware of any trademarks, patents, or copyrights that would prevent me from legally publishing this article.

All drawings can be found in this section, or at the end of this Instructable.

This is a very well thought out concept for catching small hive beetles through the use of a well-made bottom board. I hope you enjoy it!

Before I began keeping bees, I searched the Internet for good management practices. Because of this, my hives are mounted on and moats, I use Bacillus thuringiensis var. aizawai (Bta) to limit wax moth damage to stored comb, and I use two homemade solutions to combat varroa mites. I also use a small hive beetel trapping bottom board beneath each hive. The bottom board I describe here is the latest of three designs I've used since starting beekeeping. In 2009, I installed two packages of Italians (from Georgia, 67$ each) in my half-acre suburban back yard. I've not bought a single bee (nor accepted any bees offered to me) since then and have averaged 10% overwinter losses. The bottom boards made for this article are essentially the same as the one that won the blue ribbon at the Maryland State Fair ("Bee Related Gadgets" category) in 2016. Construction has been simplified: pine, rather than oak, is used and the drawer is less bulky and complex.

The bottom board kills small hive beetles (SHB) as follows:

An oil pan is located directly beneath a slotted aluminum sheet that serves as the bottom of the bees' living space. Bees harass small hive beetles and the beetles enter the slots to escape. Once they enter a slot, they fall into the vegetable oil and die.

A test done before submission of the bottom board in the Maryland State Fair demonstrates the effectiveness of the bottom board. I cleaned out the oil pan and refilled it with fresh oil, and then photographed the contents 27 days later (6/27/16-7/24/16). More than 100 small hive beetles were trapped, as determined by counting the beetles that appeared in the photograph. More recently, a fellow beekeeper (Richard Ochs, October 23, 2017) built a bottom board based on my design and reported that he "got about 30 beetles in 2 days" after installation.

Tools:

• Miter saw
• Table saw
• 1 1/4" forstner bit
• Router
• Tack hammer
• Slotting shears (0.110")
• Center punch
• Hammer
• Square
• Tape measure
• Marker or pencil
• Drill
• Drill bits
• Rotary grinder
• Stapler

Supplies:

• Pine 2x4s (74" total length)
• Pine 1x4 (13 1/4" length)
• 3/16" actual thickness plywood, underlayment grade (13 3/4" x 1 1/2")
• Wood glue (outdoor grade)
• 1 5/8" coarse drywall screws
• 1 1/4" coarse drywall screw
• 1/8" mesh wire screen (galvanized)
• .010" thick aluminum flashing (20" wide x 28")
• 3/8" staples (stainless steel, about 32)
• 1" or 2" wide HVAC aluminum foil tape (about 24" long)
• 1, 18 gauge aluminum, wire-in-rim, sheet bun pan (13" x 9.5" 1/4)
• Slotting shear (.010" width)

Parts:

• Long Sides (2) (3 1/2", 1 1/2", 20 1/2")
• Front (2 3/4", 1 1/2", 16 1/4")
• Back (3 1/2", 1 1/2", 16 1/4")
• Bottom* (1/16", 13 3/4", 18")
• Brace (1 3/16", 3/4", 13 1/4")
• Drawer Front (1 3/8", 1 1/8", 13")
• Slotted Sheet** (.010", 14 1/2", 18 3/4)
• Drawer Sheet** (.010", 13", 13")
• Louver Sheet** (1 1/8", .010", 12 1/2")
• Rain Guard** (.010", 1 1/2", 16 1/3")
• Drawer Front Screen*** (1 1/2", .010", 13 3/4")

Materials:

* 3/16" plywood

** .010 aluminum screen

*** 1/8" mesh galvanized wire screen

Lengths of 2x4s for the four sides of the bottom board are cut about 1/2" oversized to allow for waste when mitering.

Each piece for the sides is mitered at a 45 degree angle (to the cut length listed) so that they fit together as in a picture frame.

The depth of cut for the table saw is set to 3/4" and the table saw rail is set at 2 3/4" from the inside edge of the blade.

The first cut is made in three sides ('Long sides' and 'Back') that will remove a 3/4" x 3/4" section of wood.

The blade of the saw is raised so that it will cut through the side labeled 'Front.' This will make the entrance for the bees at the front of the bottom board.

The blade is lowered so that it will cut 3/4" deep, and the rail is adjusted so that the outside edge of the blade is 3/4" from the rail.

A second cut is made in the long Sides (2) and back is made to remove a 3/4" by 3/4" section of wood removed.

This is the appearance of a side with the 3/4" by 3/4" section removed.

The rail is adjusted so that a 3/16" slot, 1/4" deep, is made to accept the plywood 'Bottom.' The slot starts to extend at 3/4" from the bottom and extends far enough upward for the plywood to fit snugly when glued (about 3/16"). If the saw blade is not wide enough to make the slot in one pass, multiple staggered cuts may be needed. The 'Front' piece is shown in the picture.

End view of one of the completed 'Long Sides' that shows the profile made by the table saw cuts. Dimensions are given in the drawing Cross section: Long Side. This drawing can be found with other drawings in the introduction, or at the end of this 'ible.

Now the large slot is made in the 'Back' piece through which the oil pan drawer will slide. A 1 1/4" forstner bit is used to drill holes to start making the drawer slot. The bit is centered so that it just kisses the slot for the 'Bottom' and the 45 degree chamfer at the end of the piece (as shown). Holes are drilled at both ends of the slot.

A jigsaw is used to remove the majority of the wood to make the slot. Two cuts are made that extend from one hole to the other, as shown.

A router is used to shape the drawer slot to the final dimensions of 13 1/4" by 1 7/16."

Hand filing cleans up and sharpens the corners. The slot is now in its finished form.

Not shown: The 'Brace' piece is cut to size from a 13 1/4" length of 1x4 (3/4" thick pine). See drawing The Brace for dimensions.

Dry fit the 'Bottom' to the four sides. Use a square to mark the centerline for the Brace and drill three countersunk holes (evenly spaced) for the 1 1/4" screws that will connect the 'Brace" to the 'Bottom.' Consult the drawing Partial Assembly: Bottom Board for clarity.

While dry fitted, drill countersunk guide holes for the 8, 1 5/8" screws (two at each corner). Also drill the countersink guide holes for the two 1 5/8" screws (one for each 'Long Side') that connect the 'Long Sides' to the 'Brace.'

Apply glue to the mating surfaces in preparation for glue-up. I use carpenters (yellow) glue and an acid brush. However, an acid brush is optional.

Glue is brushed into the groove for the 'Bottom' and then the four sides and 'Bottom' are assembled.

This picture shows the 'Back' which was the last piece assembled. being placed in position. Before the glue sets, Care is taken to make sure the corners are square and all pieces are fitting snugly.

Also before the glue sets, the eight screws for the four corners are used to draw the mating surfaces together. The 'Brace' (not shown) has glue applied, is inserted, then screwed into place with three screws from the 'Bottom' and one from each 'Long Side.'

Here is the appearance of the bottom board after Glue-Up. Excess glue has been wiped away while still liquid. This is the stage of construction for the drawing Partial Assembly: Bottom Board. The first picture is a view from the top, and the second picture is a view of the bottom.

After Glue-Up, the countersunk screw holes are filled with an Epoxy-based body filler, then sanded flush with the wood when cured.

Eleven 1/2" holes are drilled with one inch between the centers starting at 1 1/4" from one end of the 'Drawer Front.' Consult the drawing Drawer Front for clarity.

The 'Drawer Front' is slotted with the 1/8" wide table saw blade to make the slot that will contain the 'Louver Sheet.'

A piece of aluminum flashing is cut about 2" longer than the finished sheet length for the 'Louver Sheet' to make room for staples at either end. The 'Louver Sheet' is then stapled to an oversized sacrificial board. A top oversized board is screwed to the bottom one to sandwich the aluminum sheet(s) for drilling. Multiple 'Louver Sheets' can be drilled at one time using this arrangement.

Eleven 1/2" holes are drilled with 1" between centers to make the holes in the 'Louver Sheet.' Refer to the drawing Louver Sheet for dimensions.

Here is a view of the partially complete 'Louver Sheet' with holes drilled after the top section of the drilling jig is removed. The ends of the sheet must be trimmed to the finished length so that it will operate properly in the 'Drawer Front.'

The second photo shows the louver action. In the winter I close the ventilation holes; in the spring and summer I open them by sliding the 'Louver Sheet' by 1/2" within the slot in the 'Drawer Front.'

At this stage of construction, the partially completed, glued-up bottom board and 'Drawer Front' (minus all sheet aluminum parts) are immersed for about ten minutes in a melted paraffin and gum rosin solution (at about 120 degrees Fahrenheit) to extend the life of the wooden parts. Treatment of a medium super is shown since illustrative photos of the bottom board dipping are not available.

The 'Drawer Sheet' is now cut and shaped to make the drawer that will hold the oil pan. First, a 90 degree bend is made to form the 1" tall back end of the drawer. Since I don't have a sheet-metal break, I clamp the sheet in a vice to assist in bending.

A slight (approximately 20 degrees) is made in the front end of the 'Drawer Sheet' so that the rain will be diverted away from the oil pan drawer when the bottom board is exposed to the weather.

After the sheet has been bent front and back, it is checked for fit within the bottom board. Then the 'Drawer Front' is stapled in place. A tack hammer is used to drive home any staples that stand proud.

Here is a photo of the completed drawer with the oil pan in place. See Assembly Drawing: Drawer for dimensions of the assembled drawer.

The Slotted Sheet is fabricated with the assistance of a template. A template can be made from the dimensions given in the drawing 'Slotted Sheet.'

After flashing is cut to the major dimensions of the 'Slotted Sheet,' the template is attached and a center punch and hammer are used to mark the beginning and end point if each of the 24 slots.

Two additional divots are made using a center punch so that three 0.110" holes will provide access for the slotting shear used to cut the slots.

After three holes are drilled for the start of each slot, the holes are conjoined into a short slot with a rotary grinder. The resulting slot will allow entry of the slotting shear.

A 0.110" slotting shear is used to cut each of the 24 slots.

Keeping the slots .011" wide or less is important. If the slots are too wide, or some portion a slot is too wide, bees will access the oil pan and die. To avoid this, apply tape as described next.

Due to their odd shape, the starting slots made by drilling and grinding may allow bees to access the oil pan. This is remedied by applying a strip of aluminum foil HVAC tape to cover the starting slots. I have found that no bees are killed when this fix is made and that adhesive backed aluminum foil (aluminum foil HVAC tape, not cloth backed 'duck'- or 'duct'- tape) last for about seven years in the hive after application.

After the 'Slotted Sheet' has been completed, it is secured to the bottom board switch stainless steel staples along each edge and along the 'Brace.' Staples that stand proud are driven home by tack hammer.

The 'Drawer Front Screen' is cut to dimension from 1/8" mesh galvanized screen and attached with five evenly spaced staples as shown. The screen covers the louver holes and overlaps gaps between the 'Drawer Front' and the 'Back' to prevent the entry of small hive beetles and other insects.

The 'Rain Guard' is cut from flashing, bent at a 20 degree angle, and secured to the top back edge of the bottom board with staples. The rain guard prevents rain from from entering the drawer. I remove the exposed sharp corners of the drawer and 'Rain Guard' by cutting them off.

The bottom board in use. A standard 10- frame Langstroth hive entrance reducer fits, as does standard 10-frame woodenware in general.

The bottom board drawer is accessed from the rear of the hive to clean the pan and add new oil, or to open or close the louvers.

Filling the oil pan of a new bottom board. I use inexpensive vegetable oil to fill the pan. I replace the oil once or twice a year, depending on how much detritus (wax, dead beetles, etc.) fills the pan.

Improvements to manufacture such as punch-and-die fabrication of the slotted aluminum sheet (or some other method) could aid in mass production of the bottom board. Other improvements might include CNC milling of the drawer slot and / or other features of the sidesand 'Drawer Front' that are laborious to do as described here. The bottom board as constructed in this article has worked in reducing one of the may stresses on my bees and may have contributed to the good health of my colonies over the past eight years.

For details on construction, see the mechanical drawings in the Intro section or, in this step.