In one of my Filament orders I thought I'd try a sample of thermochromic ABS. It changes from dark green to yellow with a change in temperature. So I thought it would be cool to make the layer and PEEK fan housings out of it.

- Cold.

- Hot.
Works pretty well doesn't it? It changes colour almost instantly once the hotend is on.
If anyone wants to buy any (In the UK):
http://www.shop.3dfilaprint.com/abs-175 ... -510-p.asp
You can get in in different colours too.