After months of building, (still not 100 % yet) and weeks of late season 90+ temps we finally had a 40 degree day !!! I was able to fire up my rocket. YES !!! As i was warned it did not roar at first, in fact it did its best to smoke out the greenhouse. It did draft rite away but then wanted to back up the feed tube. I spent about half an hour holding a small fan blowing down the feed tube and that was all it took, as the core and heat riser heated up the draft took over on its own and soon i had a dragon trying to roar! As i have been building all summer on this, my cob has had time to start drying. I think if this was a fresh build i would have had more trouble getting it to draft on its own. Using a digital temp gun, I was getting temps at the center of the barrel of 950+ the top side of the barrel was running 675 or so. My pipe where it rises up from the cob started out at 61 degrees and after 4 hours of running it was at 130+, up the vertical pipe a few feet it was running around 85 degrees. At first amazing an amount of steam & smoke was coming out the vertical stack but then reduced to just a small plume. After about 3 hours i started to get a drip inside from the joints of my stove pipe (even though they are metal taped) a bucket on the floor catches this and i expect it to stop as every thing drys out. I do need to seal up my ash cleanout access as i was getting smoke around it and one of the drying cracks around the barrel smoked a little, but some more cob and these will stop as well. After I had it running a few hours i thought to get a camera to snap some pics. wish i had brought it out earlier to show the smoke pouring out the leaks and the clouds of steam and smoke billowing out the chimney.
Tomas Rubino : It looks like a great build, I have no Idea why you are having problems getting a primary draft, by the time you were able to start your fire, was it warmer outside?
Did your greenhouse have a vent open, up high in your roof or side wall that was trying to be a chimney ? You may have to sneak a capped off 'T" into your Vertical Chimney to allow
you to warm up the chimney before you start your Rocket - It certainly would be cheap insurance !
You have demonstrated very clearly the difference in The skin or Surface Temperatures of the 30(?) gal Drum, verses the 55 gal drum, as both of them need to radiate off the same
amount of heat energy to create the heat differential Engine that makes the R.M.H. work, the 30(?) gal drum needs to do so at a higher Temp ! Even knowing the science, it is just
counter-intuitive enough to make seeing it so much more impressive !
Again a great job, looking forward to seeing what comes next, what are you going to do about dry wood storage now ? All the best, for the Good of the Craft ! A. L.
Think like fire, flow like a Gas, Don't be the Marshmallow ! As always, your comments and questions are solicited and Welcome ! PYRO - Logiclly BIG AL
Success has a Thousand Fathers , Failure is an Orphan
When you are sneaking a T-piece into your shimney, it's probably the right opportunity to mount all the pipes with their crimps down. That way, the condensation fluid won't leak out the pipes but will run back to the stove instead.
I've been following your build Thomas, it's looking great man! Glad to hear your first burn is behind you. Don't worry, I've never met a RMH that didn't fight back a bit when starting up from cold. Now that you've got some heat in the bench it shouldn't give you any trouble until the first fire next year. A T for priming in the chimney will go a long ways to alleviating the starting pains of the first burn, but you will probably only need it once a year. Thanks for all the pictures and updates, it's been great to follow along with your build.
Location: Southern alps, on the French side of the french /italian border 5000ft high Southern alpine climate.
posted 5 years ago
Matt Walker wrote:I've been following your build Thomas, it's looking great man! Glad to hear your first burn is behind you. Don't worry, I've never met a RMH that didn't fight back a bit when starting up from cold. Now that you've got some heat in the bench it shouldn't give you any trouble until the first fire next year. A T for priming in the chimney will go a long ways to alleviating the starting pains of the first burn, but you will probably only need it once a year. Thanks for all the pictures and updates, it's been great to follow along with your build.
Matt, have you tried burning alcohol/meths? I put my wood in the J tube/bathch rocket, pour alcohol which is about 90/95° and set fire to it. Even if it draws back at first, it doesn't smoke, then gets in the right direction usualy.
Please do not atempt on a hot stove. I know what it does, and then the rocket name is there for a reason.
New update from this morning. Quit adding any wood at 8 last nite shut off feed tube at 10. Greenhouse was 10 degree warmer than outside at 7 this morning. Restart was easier than lighting my regular wood stove! Instant draft , no smoke back at all ! temps on top of barrel are over 1000 degree (my temp gun quits at that) Mass is still at 75 or so and the chimney is still dripping, its not coming from the joint after all, its dripping from the cap & running down the outside, a touch up with some calk will stop that. A quick patch with some fireclay & my cleanout cap is sealed and the crack near the barrel has been patched as well. More mass to build and i'm planning on cobbing up to the second rib on the barrel, maybe some 2"tile to look good. Using the fan to help startup worked well for me , I also thought about opening the cleanout cap & putting a propane blow torch in the horizontal pipe to preheat them. Thanks for all the replies, special thanks to matt for sharing the cast core & chimney plans. I will update later after mass is finished and dried out and i have final temp readings. Tom