Owing to the use of differing materials for the side walls, there is a slight difference in external width at the base of the Marburg box when compared with the standard version. However the construction of the base is identical,and uses the same dimensions, as it fits inside the sidewalls. The difference in external dimension is made up with a strip of plywood that is added to accept the hinge of the funnel like chute.
The base is formed from four strips of 9 mm waterproof ply and two 34 mm x 34 mm feet, rebated 9 mm x 9 mm). Strips that are 28 mm wide are suitable. 34 mm x 44 mm can also be used for the feet, with the 44 mm dimension vertical. When the structure has been glued and screwed together, ensuring that it is held square while the glue dries, then the mesh can be applied and fixed with a staple gun.
Not shown above is a plate of 9 mm ply, 383 mm x 226 mm, that slides into the grooves formed by the rebate and the capping strip. This should slide smoothly into position, but with sufficient drag so that it does not readily fall out. (Note that it is 10 mm wider than the base.)
The mesh is there so that it will provide ventilation if the plate is removed or partially withdrawn. It also allows a captive group of bees to be fumigated (future page).