First time poster so be nice 😊
My wife and I are renovating a run down double brick home at the moment on a 20acre block.
The combustion heater was absolutely useless so we pulled it out of the old chimney and are covering over the space.
We planned to install a new combustion heater on an internal wall with an exposed flue but have decided to install a rocket heater instead!
I have read two of the books and watched everything that I can find and believe that I am ready to start planning our own.
So far I have acquired two brand new 210L oil drums for free and have found a supply of 230x110x76mm (9x4.3x3") fire bricks for $3AUD each which is reasonable here.
Still trying to find some suitable stove pipe.
I'm having trouble understanding the floor insulation layer below the fire bricks. It is not well enough explained in either book for me.
I have also noticed that both the Ianto and Leslie book and the Erica and Ernie book use an ash pit which is no longer recommended which is fine.
The heat riser is also shown using half thickness bricks but I'm hoping to be able to use the full size brick if there is no problem with that?
Lastly, for brick layout is a little hard to decipher for me. He Ianto/Leslie book has a decent set of diagrams but I believe I Erica in one of her videos mention that she now makes a taller burn tunnel to leave room for ash!
Why do you suggest the batch rocket instead? I believe I have access to a friends brick cutter so the construction would not be a problem.
My wife and I like the idea of having visibility of the flames that you lose when switching from a combustion to a RMH.
The sidewinder option looks like it would potentially fit the space that we'd like to use.
In Dutch, but the pictures are self explanatory.
Benen Huntley wrote:Haha. Well our space to heat is quite large. Where did you get the plans from? I would like to try building one from old bricks outside to test.
Well, no plans. I have embarked at first, when Peter was in the last stages of development. There were no plans. For my first one. Then, for the range rocket, i went along what i had. I had to fit it withing the existing shell. Then, for my workshop one, i had to go along with the parts i had scavenged over the previous months.
I draw my own plans with sketchup. But it's often hard for me to follow these. There's always a last minute adaptation to be made etc.
But it's pish easy. Once you know the way to make your core. You can fit it in pretty much anything.
Mind you, if there is no plans per se. There's measurements.
What I've just discovered is that standard bricks will require an 'n' shape to be cut out of one of the bricks in the heat riser to get the correct port height. Or am I missing something?
Also, three bricks on their sides for the box falls 11mm sort of the required 432mm height
When i do the port, i use full bricks or cut bricks for the sides, and a brick across on top if possible.
Have you seen this http://batchrocket.eu/images/rockets/files/BrickSidewinder.skp
I did notice that it appears that using 230x115x76 bricks takes up almost the entire interior of a 55gallon drum for the heat rises.
Do you still feed the exhaust through a bench before exiting the building?
I calculated around 80-81mm for each of the 8 sides to get the correct cross sectional area.
Is it really that much better?
The 3" hard bricks will have significant mass which will take longer to heat up and get to a really efficient burn. Thinner bricks or other ways of getting a lightweight riser would be beneficial.
Keep the firebricks for the box. Buy some ready made castable refractory. Usually runs in the 25€ per bag, in euroland. You would need two bags iirc, for a full 8 inch core.
Benen Huntley wrote:Ah really? How did you go about casting the core? I've never done anything like this.
Sorry, me neither. I think Peter has good explanations on his website.
Myself, i just go to italy, and buy pizza oven slabs, and chimney refractory tubes. Pish easy i would say!
And most of the bells are made out of mass, not metal. Métal, as in the barrel, is a direct heat radiator. If you have top much metal radiator, you will overheat the house before you warm the mass.
It could of some interest.
That's a lot of fire neighs to build a bell!
Not necessarily. Here's how i built my workshop one.
This might give you ideas.
It looks like a 6" version, judged by the size of the riser. If it is, then the ceiling of the firebox is too high, that would influence the workings of this design quite a bit.
The ceiling of the firebox is done with bricks on edge, introducing too much material, coming up to working temperature will be unnecessary long this way.
The exhaust pipe is far too small, it appears to be a 4.5" diameter pipe. This should be 6"as well, plus in order to avoid stream problems, it should be at least half the diameter of the pipe from the floor and the corner, preferably more.
The top deck of the bell and the walls above the riser should have a liner of refractory material, split firebricks would be sufficient.
The ISA of 5.7 m² is a tad too much, you should expect problems starting cold. And it will be a drama getting the thing dry.
I have changed the top of the box to be a 30mm thick piece of material. Refractory concrete with reinforcement bar perhaps?
The box is 21mm higher than your specification due to the wish to use full bricks. The port is also 8mm shorter for the same reason.
Are you saying this will be a problem?
I will post an updated version 😊
The whole of the thing is within tolerances, so no new problems here. Please leave out rebar in hot refractories, the steel will expand faster, cracking the refractory.
The p-channel as drawn won't work, I'm afraid. It would be much better when you switch to floor channel, it looks complicated but that isn't really the case.
And you are aware of the fact that an octagon riser is much better aerodynamically? More complicated to build, I admit that.
Why won't the pchannel work as is? Air too hot if it is passing through the bell?
Benen Huntley wrote:Why won't the pchannel work as is? Air too hot if it is passing through the bell?
A p-channel should be situated right above the port with a small overhang. Yours is against the back wall in the drawing, beside the port. The secundary air should be fed in front and above the port itself where the lowest pressure area begins, not somewhere in the firebox, even the general vicinity of the port won't do.
This is a very tight design, I have to stress that again and again. The whole of it looks deceptively simple to build so people tend to think its workings are also simple. But you'd better believe me when I say it isn't, far from that. It took me a couple of years to even understand what laws of physics are in play and how.
The p-channel passing through the bell isn't a disadvantage, rather the other way around. See my three barrel workshop heater, that's more or less the same setup. The main reasons for me to recommend a floor channel is because it is easily replacable and it works really excellent.
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