Cast a RMH burn chamber using Vermiculite?

Hi, I live i Sweden.

I am having trouble finding stuff like triple wall pipe for the combustion chamber as shown in the video:

My question is: Can you successfully cast the whole thing using vermiculite and cement?
That is, in the video they do the following steps:
1) Isolate towards the ground using firebricks.
2) Make a U-shaped chamber using bricks. (this have two holes in the top, one that you feed sticks into, and one where the flames comes out of).
3) Put two metal pipes over the hole where the flames come out and isolate with vermiculite.
4) Put a barrel over the pipes.
5) Create the chimney.
6) Cover with cob.

I want to replace step 2 and 3 with the following steps:
a) Create the U-shaped combustion chamber and chimney using Corrugated fiberboard or other paper product.
b) Reinforcing the outside with chicken-fence.
c) Mix Vermiculite with cement and apply it to the outside of the chimney/chamber.
d) Wait until the cement mixture hardens.
e) Remove the Corrugated fiberboard using fire.

Will this work?

Sorry about my bad English...

Many Thanks
Johan

Yakumo wrote:

I want to replace step 2 and 3 with the following steps:
a) Create the U-shaped combustion chamber and chimney using Corrugated fiberboard or other paper product.
b) Reinforcing the outside with chicken-fence.
c) Mix Vermiculite with cement and apply it to the outside of the chimney/chamber.
d) Wait until the cement mixture hardens.
e) Remove the Corrugated fiberboard using fire.

Depends on what you mean by cement. Clay or refractory cement are ok... portland style cement will not work as it starts to loose its strength at 500 to 700C and does not regain it as it cools. I have seen recipes for making insulating cob bricks for this use on the web... APROVECHO comes to mind. However, any of their RMH stuff is out dated as their interests are mostly cooking stoves. They do have some of the technique you are looking for with their rocket stove (for cooking) that might help you.

I had been wondering about forming most of the internal workings of a rocket stove (mass heater) out of clay.  Situation is this -- planning to sell this place (was my grandmother's property, she died a few months ago) and move back East to be closer to my daughters and grandchildren.  However, so far NO bites on the house, which I think was priced too high (my mother is the executor of the estate, so it wasn't my decision).  I'm afraid we'll end up stuck here and the way the economy is going, could end up with no heat at some point.  Winters here are cold.  Since the house is a manufactured home, I don't see any way to put a mass heater in the house, but I could build one in the garage (have considered doing that for some time, but been too busy with other projects).  At this point, we have a barrel that could be used (would have to dump the paint that is in it, but have buckets available to put the paint in).  The barrel isn't perfect, has a big dent near the bottom which would be the top of the rocket stove, but it would work.  Just need to put that facing the back.  But, at this point, we don't have firebrick, nor flue pipe, nor the smaller barrel for a feed tube.  We do have a lot of clay on the property.  (Volcanic origin.) 

So, would it work to form the feed tube, the burn chamber, and the inner cylinder inside the barrel, all out of clay?  How about the flue inside a cob bench?  I do have some hardware cloth (rabbit cage material) that could be used for forming things like the cylinder that goes inside the barrel, or the burn chamber, etc.  That would help hold the clay together until it fired. 

Kathleen

Kathleen Sanderson wrote:
So, would it work to form the feed tube, the burn chamber, and the inner cylinder inside the barrel, all out of clay?  How about the flue inside a cob bench?  I do have some hardware cloth (rabbit cage material) that could be used for forming things like the cylinder that goes inside the barrel, or the burn chamber, etc.  That would help hold the clay together until it fired. 

It has been done... at least for the rocket stoves people cook on. The hardest part is the sand. Most sand is silicone which has a different expansion coefficient to clay. Fire brick uses sand made out of stuff that is similar to clay. If you have other volcanic rocks on the property as well as clay, the sand made by crushing that would probably work. I am not sure of cost, but refractory cement would work too. If you watch some of the RMH videos, you will find that most risers seem to be made from clay and vermiculite... the metal pipe is just there as a form... and no one seems to worry about the inside tube burning out.... if the metal goes, the clay still holds.

I think some folks over at the Rocket Stoves Experimenters Corner have tried something similar to this with mass heaters.

Take a look at the posts on casting using cardboard forms, building the internals using DIY refractory bricks and using wood ash.