How can we develop a mold with unique de-molding capabilities to disguise the exit points of the molding rods and create interior voids which increased the strength of the chair? And how will that drive the final shape of our chair?
Our first attempts at molding the chair focused on using gravity to create voids. We CNC'd foam insulation to create the general shape of the chair and slid acrylic tubes through the crocheted leg to give them volume. The resin cured on the chair in a reclining position in order to get this "windswept" look along the back edges. This method looked beautiful and full of interesting lacey details, but could hardly hold itself up.
Because the completed volumes of the legs were the only stable parts from our first mold, we grouped to figure out a molding method that promoted that. We adopted a method that used rods to stretch the crocheted form into taut completed volumes and gravity to force the chair back into the desired shape. Once the resin had cured, the rods slipped out of the MDF frame for demolding. This method was great for forming serendipitous charming wobbly shapes at the back of the legs and was impressively strong. But the crocheted form a bit too loose in some areas, too bulky in others, and we thought we could still improve the loading bearing capacity.
mold 2: the arches
We looked at the arches of Chartres Cathedral and Gaudi's Sagrada Familia to create extra strength in the seat and legs. Two crossed rods below the seat pushed up into the extra roomy crocheted seat to form arches extending from 2/3 up the legs into the seat. This became a crucial source of strength that allowed the chair to hold at least 145 lbs. It was a drastic improvement, but we still thought we could do better. The rod system has pros and cons: its great at allowing us to create enclosed volumes while still being able to remove the mold. But the rods created gaping holes in the material that could look askew, ugly or strained.
For this mold, we tightened up the crocheted form and tinkered with the positioning of our rods. This time, we Goldilocksed and the chair was too small- and consequently took weak.
Our resin application was also a problem. Because it had become a hassle to load the wet chair and rods onto the mold after we applied the resin, we tried rolling resin onto the chair once it was already on the mold. Unfortunately this created really uneven results: some areas were over saturated and became plastic-y. Other areas were accidentally skipped altogether.