Shezad Dawood, Coral Alchemy I (2022), Desert X AlUla 2022. Photo: Lance Gerber
For the site-specific biennale Desert X, Shezad Dawood worked with Factum Arte on two enlarged sculptures of corals, which were installed as uncanny, almost surreal features dotting the desert landscape of the AlUla oasis. The two species, Porites and Dipsastrea Speciosa, are native and endemic to the Red Sea.
The base volumes of the two sculptures were CNC milled in medium-density polystyrene, with the corresponding textures scaled accordingly during the 3D modelling phase. The engineering team at Factum also designed inner steel structures to reinforce each sculpture, and also aid during the process and their final installation.
For the smaller of the two sculptures (Porites), only two texture "tiles" were 3D modelled and milled in high-density polyurethane. Each tile, approximately 50x50cm in size, was scaled slightly differently to give a wider surface variety when applied to the base volumes. For the Dipsastrea, a significantly larger sculpture with a greater texture volume, approximately sixteen different textured pieces were 3D modelled and milled. Both textures were moulded in silicone.
By pouring and painting melted foundry wax (normally used in the lost wax technique of bronze casting) into the dried silicone moulds, it was possible to create a large number of malleable tiles that, when slightly heated, could easily adapt to the surface contours of the polystyrene bases. The tiles were screwed directly to the bases with wood screws and all large gaps between the tiles were filled with individually cut pieces of wax texture. Finer gaps and screw heads were simply filled with soft wax.
On the Dipsastrea, the empty joints between each tile needed to be textured: this was achieved by making clay impressions in the texture moulds and sculpting them into the joints. Lacquer was applied to prevent the clay from drying during this phase.
This process was repeated until the coral volumes were completely covered and ready to be moulded using several coats of silicone, backed with an acrylic and fibreglass jacket. The final moulds were cut and cleaned before the final cast in resin, which was done in sections.
Charlie Westgarth at work on covering the two bases with the wax-cast textures © Oak Taylor-Smith for Factum Arte
(Left) Silicone and fiberglass mould of the Dipsastrea, (right) a finished textured tile © Oak Taylor-Smith for Factum Arte
Finishing the wax-covered version of the Porites © Oak Taylor-Smith for Factum Arte
Moulding the Porites
As both sculptures needed to be able to withstand the high desert heat, kiln dried sand was added to the resin mix: adding sand helped not only to strengthen the resin, but also drastically improved its resistance to temperature and humidity. Each section was also reinforced internally with fibreglass and assembled over the inner steel structure, sealed with lacquer and primed.
After extensive experimentation with combinations and colour effects, the sculptures were then coated in thermochromic paint. This special paint, usually employed in the automotive industry, becomes transparent when heated (usually between 26º and 31º), showing the base colour coating underneath: this heat-responsive effect over the textured surface of the sculptures makes them ever-changing under the fluctuating temperatures of the desert.
Thermocromic paint under 26º
Thermocromic paint in the sun © Oak Taylor-Smith for Factum Arte
Detail of the colour-changing surface of the Dipsastrea © Oak Taylor-Smith for Factum Arte
The Porites installed and under different lighting conditions © courtesy of Shezad Dawood
The Dipsastrea installed at Desert X AlUla 2022 © courtesy of Shezad Dawood
The Dipsastrea installed at Desert X AlUla 2022 (colour when heated from the sun) © courtesy of Shezad Dawood