Used almost exclusively to keep the queen in the brood body. (this is because the queen is slightly larger than a normal worker bee and cannot pass through the slots). By doing this, the beekeeper restricts the queen to egg laying in this one box, leaving the supers full of only honey.
National grids are available separately, 17″ x 17″, for those who wish to make their own frame.
When fitting a WBC excluder, as it is square, place the excluder with the slots running across the frames. Width: 460mm 18 1/8″, Length: 460mm 18 1/8″
Slotted steel: Extremely popular. Made from 0.5mm galvanised steel and produced on Thornes own tool in the UK. Each excluder has a ¾” margin. Not as warm to the bees as a plastic excluder and can be prone to buckling; this is due to the excluder lying flat and in close contact with the frames. The bees then propolise the occasional spaces between the excluder and frame top bar making their removal quite difficult at times. Slot is in a staggered pattern and measures 4.3x19mm.
Framed stainless steel: NOW WITH STAINLESS STEEL GRID – ideal for use with MAQS or other chemical treatments. Fit with the bee space on the underside, ensuring the bees have free access over the top of the frames through the single bee space created. The wooden corners of all wire excluders are half-lapped, glued and stapled. The wire grids are screwed in place to ensure a firm hold. By using this type of excluder you will minimise wear and tear to bees’ wings and bodies. They are generally stronger than the slotted type of excluder and should provide years of service.