Rocket Mass Heater Cast Core Plans

[matt walker]

Wow, cool! I'm thrilled George, thanks so much for sharing that here. It looks like you did a neat job on the core. It seemed to be burning well in the short clips there, be aware that it takes quite a while to dry and will burn progressively better as it does.

Is your feed extension temporary? Be careful of creating too much of a chimney there as it works against the draw of the rocket.

Great job man, thanks again for showing us your work.

[matt walker]

I just watched your cob harvesting video George. I LOVE your trommel! Can I share that here? I bet Guy wants one to separate his rocks from his other rocks.

[georgesr]

Matt,
Yes the piece of chimney pipe in the feed tube is temporary, it's being used to mold the round shape to the feed tube opening. I have another short piece of pipe in the front of the mold in case I try a batch load, I can just knock out the plug. Then I will use a chimney plug to close the feed tube. I should of taken a photo.
I built the trommel to sift compost and it works great to remove the rocks, grass and large chunks of clay. You have my permission to use any of my videos.
George Sr













g

[matt walker]

Thanks George, I can't wait to see your core in a finished stove. I like the idea of fitting a cap for converting the feed.

[pdk17]

Hi Matt.

First post! I read about every post on this forum and check daily for new posts and replies. I especially like your RMH posts! Very inspiring! Thanks for your effort (and from all others too!)

Right now our new bio ecological house is being build. Most of it's construction materials are organic of ecological (wood,cob,calcium silicate brick,poroton brick,...) It wil be highly energy efficient. And I am dreaming of building my own RMH soon.

I dig the Cast Core! I was just wondering, if you would want to have an outside fresh air inlet, where would it be if you look at your Cast Core? The contractor put a 20cm (8") pvc tube through the concrete slab that is sticking out somewhere near the area the burn tunnel wil be located. I really have no clue what the connection of that air inlet and the cast core should look like. Is there a certain diameter it should have? Probably the diameter of the Cast Core right? Can it get hot? Does that put the pvc pipe in danger in a way?

Some pics:
The house

The permaculture garden (with rootcellar in the back and hugel in the front)

The livingroom where the RMH should come. Note the air inlet PVC pipe sticking out of the slab.


Many questions. Thanks in advance for some hints

grts from belgium
Piet

[matt walker]

Hi Piet, welcome! What a great project you have going there, it looks like it is going to be a wonderful home.

As for the outside air intake, I have a few ideas but I think the simplest is often the best. I personally would not couple the air intake directly to the stove. Often in the course of running the stove it is necessary to adjust the intake size by covering the feed partially. Additionally, depending on fuel, there are times when it is important to be able to cover the fuel while burning.

Due to this, and with simplicity in mind, I think I would finish the air intake to be an open hole right next to the feed of the stove. Design a way to close it completely, whether it's something as simple as a plate over the hole, or a mechanical damper or the like. Now, when burning, if only outside air is desired, a container could be placed over both the feed and the air inlet, thereby coupling them and isolating them from the living space. I do something similar when I leave the stove unattended, I invert a metal pot over the feed with a little opening on the bottom to allow air in, but no potential for sparks or embers to get out of the stove. In this way you can block off both air inlet and feed when the stove is not burning, and also couple them, or run it open to the room, which is very cozy feeling. I hope that's clear, it's a bit hard to describe. I could maybe try to draw up what I mean if you need a better description.

That's just one idea, I'm sure there are a lot of ways to do it satisfactorily. I can't wait to see this project develop. Thanks for sharing it with us!

[pa_friendly_guy]

Hi Piet, welcome. I agree with Matt that you have a wonderful project being built there for your Home. Matts idea if keeping things simple makes a lot of sense to me. I do not think I would advise hooking the PVC pipe directly to the burn box of the stove for safety reasons. Having a way to cover it and close it off completely when not in use is a great idea. Then making a metal pipe that would fit snugly over the out side air inlet and curve around to the burn chamber and fit snuggly over that as well should work very well for your purpose. I would suggest a screen over the end of the pipe near the fire box to arrest any sparks that might fly up and get down to the plastic pipe and installing a damper at some point along the metal pipe to regulate the air flow as needed. There seems to be no end to the potential modifications that can be made to a RMH to fit it to an individuals needs. Keep us posted on your progress, I would love to see more pictures as you go along.

[pdk17]

Hey Matt and Guy.

Thanks for your clear answers. Makes perfect sense, no need for drawings. I'll keep you posted on updates. First I have to convince my girlfriend (and mother of our 3 kiddies) that a rocket stove is not a hippie-weird-looking-unpractical wood stove. Maybe I'll start a post to gather tips on "how to convince the lady to build your RMH"

I'll sure post updates a long the way. We're really at the beginning of our permaculture-adventures. No dirt under the nails yet at all... But that will change soon as spring arrives and we're going to design the garden. Keep you posted with pictures for sure (I am professional photographer)

Piet

[pa_friendly_guy]

There is another permaculture site that I used to get on a lot until the owner of the site set out his plans for world domination, anyway there is a thread there about trying to hide the barrel, or improve the look of the barrel in a RMH in your living room. They can be painted with stove black. It is a watery paint that will stand a lot of heat. Unforfunately it will turn gray with time. Some people have gone to the Hardware store and bought hardware cloth. That is a thin metal product with a pattern stamped though the metal. It comes in different colors, gold, silver; brass, aluminum, etc and can be bent in a semi-circle around the barrel easily. Pick a color and pattern that you like and let an inch or two from the barrel to the metal filligree work, you may need more than one piece to go all the way around the barrel. The heat might discolor some of the paterns or colors, so pick wisely. The top of the barrel is still exposed so you can still boil water, make tea, add humidity, or cook on the stove if need be. The added metal around the main barrel might also add just a small bit of added safety with small children, it would shield the heat of the main barrel from touch while still allowing all of the heat to circulate from the barrel. It was the best Idea that I had seen for hiding the barrel look. BTW My oldest son calls my permaculture friends, my Hippy Dippy Friends. lol, so your wife is in good company if she thinks we are all burned out pot smoking hippys from the 1960's I don't know about the rest of the group, but I for one an not nearly burned out just yet, I won't comment on anything else, because I did grow up in the 60's

[mannytheseacow]

I really dig this cast core build and would like to model my RMH around this. My current chimney vent is 6" and my life would be a lot easier if I kept this outlet. Any thoughts on reducing this design to fit the 6" outlet?