Our starting point for the City of Vancouver manhole covers was to design a new system of fabrication, yielding unique results in each iteration of the procedure. Thus, the form of each manhole cover is born completely from the process of making, rather than from an abstract idea in the author’s imagination. By working with a material’s intrinsic qualities, and allowing it the freedom to move naturally, we discover new forms that have a certain appropriateness that conventional, arbitrary form making often lacks.
This way of making objects challenges our expectations and invites us to see beauty in unexpected places.
The technique we developed is an interpretation of the process of sand casting. We use conventional moulds only to create the flange necessary for seating the manhole cover into the street. We then place an aluminum stamp spelling out ‘CoV’ over the casting bed. Next, we cover the casting bed with loose sand, blow air into the sand to make an unpredictable shape, and pour liquid metal into the resulting cavity. When poured into the sand, cast iron has the wonderful quality of having very strong surface tension, creating a very pronounced meniscus edge around the perimeter of the pour and at the locations where it interacts with the lettering of the stamp. This meniscus edge gives the manhole covers a liquid quality, or the impression of inflated balloons, which contrasts powerfully with the weight and material quality of the solid metal.
This fabrication technique cannot be repeated – every casting is entirely unique. As a result, every manhole cover is different in shape from any other. What better reflection of our city than a series of liquid metal puddles, echoing the sound of rushing water both above and below.