The 36 hour coil was one of my SSTC coils based off Steve Wards mini SSTC schematic.
It stays cool but I still programmed an idle mode between songs. It plays part of the halloween movie theme song
then does a 2hz burst mode which looks like a fake 6 inch QCW coil .
The oneTesla coil gets up to 140 F after the beetle juice midi file played at full power
It then drops back down to room temp in about 2 minutes.
Set yours up with a temp sensor and run it for an while to see what it does.
Short video with temp gauge
http://www.youtube.com/watch?v=fUhA-Q3jU-4Beetle juice zip file from Stegu
download/file.php?id=117