Cheap hot water heater....

[NM_Shooter]

I was looking at the "Living with no income" thread and saw the posting on the ZODI Outback Gear Fire Coil Water Heater.  This made me remember a water heater that I tried to make a long time ago. 

Rather than have a flat water heating coil, I tried a vertical spiral of copper tubing.  I had hoped to be able to create a self-circulating effect, either from convection or through "percolation".  I only fiddled with it for one evening, and was unable to get it to work.  I may have to go back and give it another try. 

My goal was to have a coil within a 4" pellet stove vent tube, and heated using a small flame source such as a bunsen burner.  Much like using the pilot light to keep your RV water hot.  I also thought about wrapping this tube around the vent for a wood stove.  That might put too much energy into the tubing though.  Probably only need a small amount of contact area. 

[Don_P]

A friend gave me an old 100 lb cylinder that someone had repurposed into an air tank at some point. I've thought about cutting 6" holes in each end and passing a piece of 6" schedule 40 pipe through the cylinder as a flue, standing it on top of a woodstove. The top would need a 2" fill/ pressure relief hole that remains open to the air in case it did boil. Another version wandering around up there is to make a manifold space at each end and pass multiple 2" flues thru the water. That would give faster recovery but would probably need a large open vented storage tank hooked to it that it circulates through. I've been wondering about something along those lines for heating the shop floor.

Off topic, at one point I kicked around the idea of making steam and spinning a generator from the woodstove. A little research put that to rest real quick. First, the fire is intense and constant, more than I could use or would want to tend. If you trap pressurized steam it has tremendous potential. If a boiler breaches, and the pressure that is keeping a quantity of water from boiling is released, the entire volume of superheated water becomes steam instantly. Steam has something like 600 times the volume of water. The house would be in the next county 

[NM_Shooter]

They used to make steam cannons!  Hmmmmm........

[fishing_guy]

[embed=425,349]<iframe width="420" height="315" src="http://www.youtube.com/embed/jbreKn4PoAc" frameborder="0" allowfullscreen></iframe>[/embed]

The action happens at 1:17 of the clip.  Be careful out there.  Sometimes safety is worth the few extra $$.