polystyrene/foam help!?

I did a project where we used foam. (we used inch thick foam. about 1.5 metres by 2.5 for about $10. seconds from a factory) We used electric knives (as in cheap kitchen ones)to cut out patterns and then used rubber cement to glue them into the 3d shape. (Keep the windows open!) We used an air compressor to spray paint them, which was cheap and effective, as we used one main base colour. details were done by hand later. I found foam better to work with than polystyrene. we trialed polystyrene and decided on foam.