hi all I built a solar and wood fired water heater for myself...i followed all the safety rules and it is working well. My waterjacket is an expensive welded stainless steel tank ($280). Now i'm building one for a neighbor. I'd like to build a less expensive waterjacket for installation inside the woodstove. I was planning on using flexible copper and hiding it behind a steel plate in the firebox so it wouldn't be damaged while wood was being loaded into the stove. I'm wondering if I build an exposed galvanized set of pipes if it would be easier, cheaper, stronger and better at conducting the heat, as it would be exposed directly to the fire, rather than from behind a plate. I'm wondering if screwed together galvanized water pipe would develop leaks at the threads if it were installed inside the firebox of a woodstove. The water in the pipe will be under standard house pressure, by the way. Does anyone have any thoughts or experience?