The device above is part of what is called a “bubble pump” from a coffee maker. It is an aluminum tube with resistors wrapped around it. The resistors get current and heat up the fluid in the tube. In the coffee maker there is a one-way valve on one end of the tube. The water in the tube heats up and gets to the boiling point. When it boils it pushes out in both directions from the tube. The one way valve activates and then all of the boiling water is pushed out by its own pressure to the coffee. That is how 99% of home drip coffee makers work. Neat, isn’t it?
You can dig one of these out of almost any coffee maker you find in a thrift shop or on the side of the road. It will be in the base of the unit, under where the pot rests. There may be a lighted switch somewhere in the middle. Keep that – it may be useful when you build your enclosure.