posted 11 years ago
Short answer: go search "masonry stove" "masonry heater" "Russian stove" and "Russian heater".
Long answer: The need for small splits isn't about moisture content, but about air contact. If you've got just one fat piece of wood in your feed hole, then the air can only touch the outside surface, and the wood can only burn on the outside surface. If you split the same piece into four pieces, then think about how much more surface area it has.
I've also wished for a way to extract more heat out of a wood stove already in place. I don't think there's a good way. (Although, I did see a fella who made a "masonry hat.") The high temperatures that you're trying to achieve are right around the melting point of steel . Even if you fell well short of your target, you'll still be accelerating the corrosion and deterioration of the wood stove. (In addition, I suspect that the expansion and contraction of steel vs. the cob would promptly crack the arrangement apart, although I haven't seen this happen in real life.) If you have an abundance of clay, you might consider making old fashioned adobes and building a masonry stove. The firebox will need to be refractory, and can be any style you prefer, including a batch rocket. That, at least, is my own plan for next summer. Best of luck!