So, you're saying the feed, burn tunnel, and heat riser interior are the only things that CANNOT be metal? The barrel and connected piping is OK? What would be a good material for the feed, burn tunnel, and heat riser interior?
Just ordered "the book". While I'm waiting can somebody answer a question? I've read several posts saying "metal is dead". What do you use for the barrel and piping if not metal? I'm researching a rmh for a new greenhouse build.
