A bit of an update...

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.

Is that single skin flue pipe Jeremy?

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 !  

Keep us posted.

Tomas, there is no risk of melting abive the barrel whatsoever. Even to reach aluminium melting point, ils not feasible i think.

I would suggest adding a T to the end of the chimney so no rain gets in there, and might help manage gusty wind a bit.

Awesome. Thanks for all the input. Will keep yall posted as I continue the build.

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.  

Doesn't galvanised pipe give off toxic fumes when heated?

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.

Good to note for when I build one in the house.

Just a quick update for you guys who gave me advice. I put more rock in the bench and had to knock the feed tube down one brick. The feed tube was too tall and it was creating draft issues. I took the top layer of bricks off and now it rockets right away even on a cold start. No drafting issues... no back drafts. The hound slept right on the top.

Im almost done with it. Just have to dry the cob out a bit, get some metal tape for the seams, patch up the spots at the top of the feed tube, and clean the rocks and slate a bit more.

Linseed oil after it dries???

I used Linseed oil on my Batch Box brick bell and it has worked very well.

John Harrison wrote:I used Linseed oil on my Batch Box brick bell and it has worked very well.

Awesome thank you

Jeremy,   Depending on how much you want your barrel to look pretty, you could also put some linseed oil (or other) on it as well....with maybe a bit of cleaning first. Other than the more shinier, polished look, it will also help to prevent it from further rusting as well - in particular where cob meets the barrel or on top where kettles that dribble a little make rust rings. Just be warned though, that first fire (or two) will cause the oil to smoke-off and make your place stink for days! Open all doors and windows if you do this. Don't ask me how I know but I also don't regret doing it.

You could also take the barrel outside and start a fire in it after you've cleaned it up, and then rub your oil of choice on it. This would be like seasoning a cast iron pan I guess, so does the choice of oil matter as far as smoking point? In future use the barrel will get very hot on the top, but if "seasoned" properly where the layers all smoke as applied, perhaps the future normal use wouldn't smoke any more?