I wanted the base to
have adjustable feet,
have recessed panels for the controls and power,
have integrated tubes that will accept the aluminium loops for the fabric form.
The mould was made from melamin coated mdf. The central inserts that will need to be removed after casting were pine, covered in modelling foam and then layers of packing tape. This allows a bit of wiggle for removing the inserts.
Tubes for the aluminium supports were held in place with short lengths of the aluminium rod (also keeps the concrete out). Nuts for the front panels and LED plate were also cast into the concrete.