![](https://static.dezeen.com/uploads/2008/01/max-lamb-bronze-poly-square-2.jpg)
Bronze Poly Chair by Max Lamb
British designer Max Lamb has sent photos and text explaining the making of his Bronze Poly Chair, a recent design that involves hand-carving a polystyrene chair and then casting it in bronze.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly01.jpg)
The project combines techniques from two of his previous projects, Pewter Stool and Polystyrene Chair.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly02.jpg)
Lamb calls the casting process "lost foam", as it is similar to the lost wax technique but substitutes a wax original for one of expanded polystyrene.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly12.jpg)
Lamb exhibited the chairs at Design Miami in December with the Johnson Trading Gallery of New York.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly11.jpg)
Here's the text from Lamb:
--
Sacrifice and Investment - Bronze Poly Chair
A series of unique chairs cast in Bronze using the 'lost foam' casting process.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly03.jpg)
The Bronze Poly Chair combines two processes I have explored in previous projects - my Pewter Stool that was cast directly into a hand-carved mould on a sandy beach in Cornwall, and my Polystyrene Chair that is carved from a solid block of low density expanded polystyrene (98% air) and then coated in rubber.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly04.jpg)
Each Bronze Poly Chair is hand-sculpted in polystyrene foam and then buried in sand ready to be sacrificed.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly05.jpg)
Ingots of bronze are heated to over 1100 degrees C and the 'red hot' molten metal is poured through the sprue into the sand, consuming the delicate foam and investing the hidden cavity in bronze.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly06.jpg)
Over two hours of waiting and the solid bronze replica of the foam object is broken from the sand.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly07.jpg)
With only one attempt to invest the foam in bronze, every sacrifice is a risk.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly08.jpg)
Successful or not, each casting requires a new foam pattern ensuring no two chairs are the same.
![](http://static.dezeen.com/uploads/2008/01/bronzepoly09.jpg)
![](http://static.dezeen.com/uploads/2008/01/bronzepoly10.jpg)
![](http://static.dezeen.com/uploads/2008/01/bronzepoly11.jpg)