So just a quick thought:
Is there a good reason to not use thermal paste between the element and hot end? I would have thought it would make for much better heat transfer.
so long as you get paste that can withstand 340c+ remember that the heater element will have to put out more heat then what the thermostat reads because of the material in between them. The other option is to wrap the heating element in tin foil, clean and easy to remove later.
Yea, temp resistance seems to be the problem with traditional thermal putty you use on a CPU.
Would guess it would also have to be non electrically conductive so as not to mess with the element.
Been there, done that, spent a decent chunk of cash on very-high-temperature heatsink grease. Used it on the thermocouple, the heater, and where the heatbreak/feed tube meets the heatsink. Doesn't make a damn bit of difference in any of those places.
Haha, cheers Julia!