Yes, something quite contradictory.
Ok, on winter treks I'm carrying a thermos bottle (vacuum insulated steel bottle to be precise) plus a kettle to heat water. Could one pot serve both purposes? Carry drinks in a thermos and when it's time to refill, pour cold water in, use the heat exchanger cap and heat it up. Then switch back to insulating cap.
Test with a piece of closed end alu tubing. Tent pole reaches to the bottom of the inverted thermos bottle and serves to let out pressure.
Worked. Water boiled. Didn't explode.
Impossible to cook anything but liquids. Hardly lighter than a simple kettle but brings other advantages: No waste heat from pot, so would allow use of alcohol burner, candle, GattGen or other nice quiet low power burners in cold temperatures (Usually lots of heat is wasted from the kettle if cook times are long)
Possibility to add a pressure cooker valve with own risk.
A more refined plan to be used with Thermos brand FBB and Stainless King series with o-ring of their original caps. Tad expensive and still missing the pressure relieve tube so a guaranteed explosion. Please don't print and use.
https://www.shapeways.com/model/1666424/hx-cap.html?li=aeTabs
