Why not use cast iron or even boiler plate - good enough for wood stoves and cooking ranges for centuries past. I used recycled heavy steel tube for my rocket stove and I am confident it will last many years
We have a bin by the gate for our neighbors to put their grass cuttings in, we get more mulch and compost material than we can cope with! We have told them no cuttings from lawns that have been sprayed or going to seed grass. Works well for us.
