Pressure pump, to coil of copper pipe,inside a open top drum to contain the heat, oil or gas burner to heat the water in the copper coil, MOST SURE a pressure relief to avoid shapnel, a handle with a nossel to direct the steam, if using a valve it must also cut the heat and by pass the pressure pump when closed so the whole thing doesn't go ballistic.
If you ever see a old "Steam Jenny" (brand) you will think it is easy to build your own if you dont use a valve.
