I'm starting a new thread here for this subject. Not sure how to erase the old one.
Yesterday I started disassembly of the existing fireplace. It's mostly dry stacked together, with large firebricks and some other concrete block. Jono (my partner on the project) identified the main challenge: "How to place the barrel over the heat riser?" We discussed a possible solution of placing the combustion barrel (30 gallon) and the heat riser (triple wall pipe) at the same time. Jono has been promoted to genius consultant .
Next step is to build the mock core outside and do a demonstration.
A few photos to introduce the fireplace. This evening I removed most of the block between the hearth and the outer wall. A good section of the hearth will be temporarily removed as well to accommodate the combustion barrel... or at least tunneled out for the horizontal flu.
Yea... the main challenge so far will be fitting the combustion barrel (which I still don't even have yet ) in that space. The rock arch restricts access because it is built so low. Basing the measurements of standard 30 gal steel drum (18"x29"), the hearth, mortared together with large pink-orange-brown rocks, will have to be removed, and then rebuilt. Final positioning of the barrel will be directly up against the steel back plate of the firewall in the fireplace, where it angles toward the arches. Next step: remove the hearth stones with the Bosch hammer drill, which has been the handiest tool, so far, for busting up and removing mortar.