thomas rubino wrote:Dan; I'm no expert at this but I am learning. I would say that yes, you can plumb your 6" into a 10" mass pipe, would be like a bell . You mentioned 15' long , is that all ? How many bends ? How is your fresh air tube going to be plumbed ? We need more info to help.
thomas rubino wrote:Dan; i'm thinking no, don't reduce to 6" . Are you having draft trouble ? Is there an easy way to insulate the outside chimney ? As an experiment , when it will be dry at night , wrap fiberglass insulation around the outside chimney to see if that helps with draft. It cools of quite a bit at night in the high desert. How dry is your cob ? If your cob is green then it must dry out and heat up to draft properly. Are you closing off the feed tube after the last wood burns , or leaving it open all night ? Are you using firebrick to make your riser ? If yes, then consider making a cast riser with fireclay & perlite and using your brick to build a bigger J tube.
thomas rubino wrote:Dan; Listen to Max, he has way more experience than me.