An example insulation enclosure includes a support structure having a top end, a top wall provided at the top end, a bottom end, and an opening defined at the bottom end for receiving a mold within an interior of the support structure. Rigid insulation material may be supported by the support structure and extending between the top and bottom ends and across the top end. The rigid insulation material may extend between the top and bottom ends and consist of one or more sidewall insulation loops that extend along a circumference of the insulation enclosure.