Heatsink pastes for hotends

Having just switched off my test rig, here is the promised report on how the heatsink compound held up: After 1400 hours at 240°C with a thermal load set to dissipate about 20 watts there was no observed change in the resistance of the 18Ω resistor. There was some discoloration as seen in the photo below but no cracking or crazing of the insulation was found.



The resistor was a Vishay Sfernice RWM4X5 18Ω 3W resistor and the heatsink compound was Slice Engineering Mosquito Boron Nitride Paste purchased from Reprap World.

I think I will stay with using these resistors until something better comes along.

Mike