Permsteading.com

I have scoured the posts and have only seen one (with pictures) person build with all round, feed, burn, and riser. How is that running?
I am planning on building soon, as in I already have the materials, and I saw a post on another forum that said not to use round for the burn tunnel.
Does anyone have thoughts about that? I am using an 8" sonotube for the core, and an 8" and 16" for the riser for a total of 4" insulating factor. My wife suggested cutting 40 deg angled pieces to get a radius at transition for burn to riser.

Separate note: This is the coolest site ever.

Welcome! Glad to have you here. I haven't built a round feed/tunnel core before, but I do believe it will function just fine. I don't think it's necessary to sweep the corners, but I don't imagine it would hurt, either. Manny here has a round feed, and if I recall correctly he prefers it to the square. Frankly, these things are really forgiving. I say go for it on your first one, and if you are anything like the rest of us it won't be your last and you'll learn a lot along the way.

Thanks Matt. I am already trying to invent a reason to build another one.

BTW....My name is Todd and I'm new to the whole permsteading idea. I was convicted a few months back about the stewardship I had been displaying for my whole life. My whole career has been dedicated to destroying things. Hit me like a ton of bricks, so I started looking into ways I could live more self sufficiently and leave less of a footprint. My goal is finding a realistic way and not an idealistic pipe dream, which usually ends up in disappointment and frustration. Anyway enough of the life story.
I have a question regarding my project. I am struggling to find a way to cut the sonotube to get mitered corners, so I think I'm just going to find a 90 degree hunk of duct, and then on the feed tube end just dead end it. I was thinking for the duct to fill in the grooves with play dough (from the sons supply that doesn't get used) and then slather the whole thing with some vaseline to try and protect it long enough for the dryout. My question is for the riser. I can't seem to come up with a piece of pipe for the initial burns so I was thinking of taking a piece of cardboard with wax paper and laying it down on the core, then doing the riser on top of that. That way I can have a two piece system that is easier to move, since I'm in a rental. What does anyone think?

P.S. No I don't have a 67 GTO using up 6 miles per gallon. That's my initials and year of birth. Kind of looked strange on a site that is looking to be a better steward of our resources, I just always use that.

Yeah man, I think the idea of separating the riser and core with a little cardboard and wax paper will work fine. The joint between the two isn't that important, when you move it into it's final place you'll be sealing that area with a little bit of core mix that you seat the riser in. I think you've got a good plan going. I'm not exactly following the duct and playdough part, but I've used adjustable duct elbows in core casts in the past and they work just fine, so I think you are on track there.

I was sorta wishing you did have the GTO, to be honest. Cool initials though!

Thanks again. The play dough was an idea to create a smooth sweep, instead of having ridges inside the core.

Thanks Manny and Brew. I've watched Matt's video on the core about 10 or more times, so I know he fires it up hot right away. Have either of you two done something different to dry it out? Do you think it makes any difference? Since I needed the strength to be moved around I ended up buying the fire cement and perlite, instead of fire clay. I'm planning on getting some of that fiber reinforcing to pack in as well. I have trouble with patience, so I don't know if I can wait to fire it up

Manny will have to answer that one. I don't build the rmhs. I have only used brick and now have moved on to the super early baby stage of metal. I use the stoves for cooking and making biochar. All forms use the same basic fire science and that is where my interest in risers and tunnels comes from.

Good luck to you.