Making a chair out of recycled plastic

Here’s a neat process video where Richard Liddle shows how he makes the RD Chair. It’s an excellent idea- after melting the used plastic, he extrudes it by hand onto a collapsible wooden form, and removes the form after everything cools down. Neat stuff! I don’t imagine that you can melt just any old plastic down in this way- anyone know how to do it? [via core77]