Kenny Ng

I have spent so many hours on researching, like many others, on how to build the best Rocket Mass Heater.  I am also interested in building one without welding.  I was wondering if a hot water heater tank or a toilet tank can be used as the barrel replacement?  I know that the RMH gets up to 1200 to 1800F with possible 2200F.  

I am also interested in building the burn chamber with ceramic fiber blanket.  what is the best way to make it hold up?

I am planning to buy a Steel Stock Tank and fill it with cob, use ceramic fiber blanket to build the entire J tube;  Over it up with either a hot water heater tank or toilet tank.  Cover the base with more cob.

Reference:
https://permies.com/t/10293/Mini-Rocket-stove-mass-space
https://www.youtube.com/watch?v=7ANMXGrxgnE

Hi Glenn,

Thank you for the detailed fire tunnel.  Unfortunately the fire box is very dry.  I think i still have 5 lbs of clay and 20 lbs of sand.  I can order perlite from Amazon.  We will be finishing the heater tonight.  

Do you think it's possible to fill the fire box with left over sand to replace perlite?

Hi Glenn,

This is the clay that i ordered and i also attached a picture of the fire box for your review.

https://www.amazon.com/Amaco-45047J-High-Fire-Moist-Stoneware/dp/B0044S97BW/ref=sr_1_4?s=industrial&ie=UTF8&qid=1482544041&sr=1-4&keywords=50+lbs+clay

Thanks for the quick replay.  The feeding box is in fact hollow, Can you please tell me more about how to build the feeding box and the burn tunnel?  

You're right the top will be closed.  

I have the feeding box going directly to the secondary burn chamber, which doesn't have a burn tunnel.  The burn chamber release hot gas to the first bell on the top 3 holes.  The first bell release hot air on the bottom to the second bell.  I'm hoping that catch all the hot air with the bells.

I got the clay from Amazon.  I think it's pottery clay.  I used 50lbs clay and about 30lbs sand.

I'll wait a week to let it try before testing it.  

Thank you

So i decided to build a cob rocket mass heater with 2 bells and a little oven.  My dad and i spent the last 4 days mixin the clay and sand together and building the "castles" a little per day.  And we are almost done!  I do have a few concerns:

I don't really have a fire tunnel from the j tube, would that matter?  Would that stop the rocket effect?

I'm mixing the 5 clay to 4 sand but there's not fire bricks.  Would that not holding the heat as intended? I have read that fire bricks are clay plus sand so seems to me like i should be okay.

I don't want to test the fire until the cob is completely dry, which takes about a week.  Am i over react?

Thanks everyone, I am thinking about using it as a bell.  I just ordered 50lbs of clay and I will be going to home depot later to get some sand.  I may have enough clay and sand to build a rocket mass heater with 2-3 bells without using the stove.  I will start without the stove to see how it goes.

I was wondering if anyone has modified a parlor stove to a rocket mass heater?  I am attaching a Vulcan gas parlor stove that I would like to modified.  I am planning to make some changes to the stove and build a clay rocket stove and hook it to the parlor stove.  Anyone has any suggestions?  thank you