[Stoves] concrete rocket stoves

[Michael N Trevor]

There are wide variety of rocket stove designs shown on various YouTube 
movies.
Primarily variations on stacked hollow blocks or 6 gallon buckets with a 
removable PCV elbow.
both types have the distinct advantage of being simple inexpensive and quick 
to make.

However does anyone have any actual longevity information?

Michael N Trevor
Majuro
Marshall Islands