I have an e3d v6 hot end, that I am currently adding a thermocouple to. However, I see a few potential problems coming my way.
1) Can the heater cartridge even get me enough heat to get up that high? (no idea!)
2) 600C is getting awfully close to the melting temperature of aluminum, which the heat exchanger at at the top of the heat break is made of... so um I might accidentally melt that

3) the PTFE tubing in the hot end, which goes all the way down into the heat break can definitely not take anything near that temperature.
4) The brass nozzle should be able to handle that kind of temperature, but maybe not... I should probably get a stainless nozzle.
I have some ideas of potential solutions for my potential problems:
1) Switch to a 24 volt heater cartridge and run it off a SSR if I have to (jeesh!)
2) machine a new heat-exchanger out of brass (or maybe stainless steel)
3) use a small polished metal bushing instead of the ptfe tubing
4) buy a stainless nozzle
Ok. I'll admit this really sounds like a bad idea. Someone please talk me out of it!