So.... I'm testing different chimney configurations and I think I found one that works great without having to cut the roof. The stove went rockety right off the bat with the cob being still pretty wet and the wood being not quite dry enough. Very little smoke coming from chimney. I assume most of it is from a mix of damp wood/stove and the core not being up to temp yet. Obviously there are some details to iron out, namely heat flashing behind the barrel and trimming the pipe down that goes out the window while also closing off and flashing the window hole.
I was curious though about the pipe that runs over the barrel. I didn't that because I figured the barrel would heat the pipe causing the air inside the pipe to rise. Im assuming this will create more suction upstream causing less issues with cold starting. I could be wrong but feel free to chime in with any opinions.
Pipe over the barrel might be OK . Is it hvac pipe ? If so it might be to close to your barrel top. When your at full burn .... I don't know how hot hvac pipe can take. Be scary bad if it started melting on you during a burn... Might want black steel stove pipe there.
All your pipe joints need metal tape on them. They will leak when your mass starts drying. I would have suggested you use black steel coming up out of your mass as it is more sturdy than hvac but that will work just fine.
How tall is your chimney going to be ? In winter outside it should be insulated if it is very tall. You will need that cap on it before it rains. If its is not tall you could have wind issues .
Your build is looking great ! The mass run looks shorter usual so it really ought to roar !
The galvanized hvac pipe turns from shiny silver to a matte grey color long before it melts, and I agree that it being close to the top of the drum, like it is, would not give you any issues. I would see if you could work with the adjustable 90 elbow to create a better fit, then screw all the joints together. Tape all seams, including the adjustable elbow ones. Outside, you want the vertical rise to be taller, ideal is above the roof peak. It may work ok for now, but food for later thought.
posted 2 days ago
Doesn't galvanised pipe give off toxic fumes when heated?
Location: latitude 47 N.W. montana zone 6A
posted 2 days ago
Galvanized pipe. Yes , it does. But only once. After it has turned that grey color it is safe to have indoors.
John Harrison wrote:Doesn't galvanised pipe give off toxic fumes when heated?
More like when it is "overheated", as long as the coating remains shiny, the nasty toxins in the coating remain in place. If I remember correctly, a post on another thread mentioned a zinc chromate coating, or something of that sort being toxic when it burns off.