Foundation are sheets of beeswax or plastic that are used to guide the comb building and give support to the comb.
Foundation is not required, as bees will build comb without it. Foundation is used to guide the location and orientation of the comb. Patterned foundation also guides the size of the comb cells, which influences the size of the worker bees and discourages or encourages the production of drones.
The typical foundation pattern has a 4.9mm to 5.2mm cell size, which encourages the production of smaller worker bees. A foundation with 5.5mm or 5.6mm cells is used to bias the production of drones.
Plastic foundation starts as a smooth or patterned plastic sheet, which is then covered with a thin layer of high grade beeswax and impressed with a comb pattern. Even patterned sheets are impressed to create well-defined outlines.
Beeswax foundation is created with melted wax poured into a flexible silicone mold, or impressed onto softened wax sheets by rigid molds or roller presses.
Plastic foundation is preferred by commercial scale beekeepers. It supports comb better in high temperatures, is more robust with rough handling during extraction, and can typically be refreshed by melting off the old wax, cleaned with a hot water spray and re-dipped in melted beeswax.
Beeswax foundation can be more economical at a medium scale if labor costs are low. It is typically supported by a combination of embedded wires, external wires and side pins. The wires are made of tin plated or enameled steel about 26AWG. The same type of wire or monofilament fishing line is used for surface support, with the bees embedding the wire when they "draw out" the comb. Side pins are specially made plastic, brass or steel split pins, or repurposed 'bobby pins'. Unwired beeswax foundation is also available. It it used when cut-comb honey is to be produced, with a significant non-beekeeping market of rolled beeswax candles.
Foundation is created with only a shallow pattern of cells that serves as a guideline. Attempts to mold deep comb are complicated by the need for mold taper. The resulting wide-opening, narrow-bottom cells are rejected by bees.