Production for the final column has been started. The molds for the final are being made out of rigid insulation rather than plaster for several reasons:
1. Time. It takes seven days to prepare the plaster for mold making and out of foam, molds can be ready to use in two days.
2. There are height restrictions with the 3-axis CNC router. If molds are deeper than 5 inches, there are collisions issues with the material and the routing bit. Because of this, the molds need to be broken into sections and glued together after they are routed. This would be a difficult process with plaster.
3. Plaster molds would be made individually. By placing several molds onto one larger sheet of material, molds can be nested and use the material more efficiently than with plaster.
4. Weight and ease of maneuverability. Plaster is heavy and using foam makes it very easy to move the casts and molds around to various locations in the building a much smoother process.
There are some downsides to using foam such as not getting the same resolution that you would with plaster. Plaster has a very smooth and clean finish where the foam is a little fuzzy. For this project, picking up the tool path details are important, but the casts can be easily smoothed the day after casting.