Sounds like a great idea Big Tex. What is the size of the HWH you are considering? The one in my house is plenty big for a fine smoker. It would need a good internal cleaning and or sandblasting if you are concerned about the iron,calcium, and lime deposits. A good hot fire will burn all of the nasties away, and give a nice seasoning. Just my 2 cents, I dont sweat the small stuff!!! The air I breath on a daily basis is much worse than any byproduct a homemade smoker can produce. Good luck and have fun with it my friend!!