We buy blocks of EPS and use our CNC hot-wire machines to cut the required design, they are similar to the machines in the video. A machine with multiple wires, used for cutting squares or sheets all at the same time, is called a harp for obvious reasons.

Polystyrene is usually white, we do stock a polystyrene foam that is black, the actual colour is a dark grey/graphite. It was introduced to meet the ‘U’value standards in the building regulations, but these have been subsequently superseded.
Another type of polystyrene, known as extruded polystyrene is available in quite a few colours, blue, tan, & yellow. The colour is dependant on the manufacturer.

Whatever fascination you may have in styrofoam, I hope I haven’t bored you with this reply.
Thanks for reading.

So do you mold (and steam compress the beans), or buy blocks in bulk size and cut down to shape/size?

Is your cutting a similar computer-guided heated wire technique?

What about colour; are the beans coloured or do you spray the final mould?

I probably shouldn’t be so fascinated by all of this!

.cg

The polystyrene beans and offcuts that we create are all bagged and sent back to the manufacturer, they are ground up and reused to make new blocks of polystyrene.
Our local recycling centre also accepts polystyrene, they have a machine that compacts the scrap foam packaging into small blocks (about the size of a bundle of briquettes). We only occasionally use this service if we are short of space in the workshop.

Another question….?

How do you recycle the beans?