London designers Studio Swine built a mobile foundry and used it to cast aluminium stools from drinks cans they collected on the streets of São Paulo (+ movie).

Over 80 percent of the city's recycling is collected informally on carts pulled by independent waste collectors known as catadores. Studio Swine wanted to create a system that would help them recycle the rubbish they collect into products they can sell.

The pair collected discarded cans from a street vendor and used cooking oil for fuel to smelt the aluminium on site, turning the street into an improvised manufacturing line. They made moulds by pressing objects they found locally into sand collected from construction sites in the area.

The resulting stools have tops that bear the impressions of ventilation bricks, a palm leaf, the base of a basket, a hub cap and plastic tubing.

"Unlike the conventional aluminum furniture, they're each unique and expressive," said the designers. "Manufactured on the spot, they transform ephemeral street materials into metal objects, providing a portrait of the street."

The resulting stools were donated to the vendor who provided the cooking oil and the furnace remains in São Paulo, where the project will continue with a new series of products and furniture made in a favela.

"Mining the city for materials, the perception of the city changes," said the designers. "Where once you saw rubbish, now you can see resources to be transformed into new products."

The project was commissioned by Coletivo Amor de Madre Gallery in São Paulo and involved working with several catadore co-operatives to find both the materials to make the furnace, and the oil and cans to use it.

"Each stool takes around 60 cans, but catadores collecting cans around a football stadium on a match day bring in many thousands of cans," Studio Swine told us. "The idea is that catadores will share a furnace and greatly increase the amount of money they can get for the materials they collect."

They suggest that the furnace can be used to cast anything to sell, including small items like souvenirs for the 2014 World Cup or 2016 Olympic Games. "However, the potential of open sand casting lends itself very well to larger pieces and we are interested in how this can be incorporated into small scale architecture," they added.

Finding ways to enhance local industries by making products from waste on-site is familiar ground for Studio Swine, who graduated from the Royal College of Art in 2011 with a project that proposed making stools from waste plastic picked up by fishing trawlers, melting the material down and moulding it into furniture onboard the boat.

They're also no strangers to making and selling in the streets, having designed a mobile food stall for cooking and selling pig heads the year before.

Here's some more information from Studio Swine:

In nature, everything is interconnected and there is no concept of waste, but in cities there are lots of loose connections.
The city has so much potential, there’s a strong culture of improvisation here. The streets are busy with people looking to make a living in ingenious ways, ever flexible to emerging opportunities.

In a city with some 20 million residents the waste is on a massive scale, however over 80% of the recycling is collected by an informal system of independent Catadores, pulling their handmade carts around the streets.

We looked at the way they worked, the materials they collected, and how we could learn from them to create a new model of manufacturing – taking waste materials that could be readily found, to manufacture goods on the street, with the potential to make livelihoods extend beyond rubbish collection.

The world is becoming increasingly more globalised, something that we are interested in is how design can help retain a strong regional identity.

We wanted to tap into this existing street culture - to turn a public space into a manufacturing line. We went around the streets collecting things we can cast. Mining the city for materials, the perception of the city changes, where once you saw rubbish, now you can see resources to be transformed into new products. The city consumes a lot of fried food so we collected used cooking oil for free and plentiful fuel.

Then we needed to make moulds which are cheap and adaptable. As Sao Paulo is under constant development, construction sand can be found all over the city.

What is the future of manufacturing? Where the industrial revolution was built on the concept of making the same thing thousands of times, will future manufacturing incorporate individual characteristics or even chance?

There is something magical about the moment cold hard metal becomes a hot liquid – the moment it’s quickened and given life. We wanted the surface to reverberate with the texture of the sand and the metal’s molten state, to bear clearly the impression left by the objects we found that day.

We made stools for the food vendor that provided the waste cans & oil. Unlike the conventional aluminum furniture they’re each unique and expressive. Manufactured on the spot, they transform ephemeral street materials into metal objects, providing a portrait of the street.

Where the majority of carbon cost is in the transportation of goods rather than their production - we could see manufacturing returning to our cities, adaptable to customisations and able to ‘cast on demand’.

The potential of mobile sand casting is endless, offering another way to produce. From small items to architectural elements, it can change the face of the city.

The project was made possible with the generous support of Heineken.