I saved the green wood PDF in by "building a boiler " File. I come to this site to get better ideas for my wood burning experience. If GW is building something new I am watching. Little changes can have big results. I am a fan of refractory & simple. The R&D of building your own has some emotional up and downs, but way more ups. I buy the factory built stuff for my customers. [put it in front of them, they make the choice] I am Heating 12,000 sq ft +/- with HOMEMADE. I was inspired by the original GW & Garn, both very simple designs.