one-minute Rocket Mass Heater--reviews of this?

http://www.mnn.com/earth-matters/energy/blogs/how-to-make-your-own-rocket-stove-with-a-few-cinder-blocks

My housemate just sent it to me.

Pro's:
it can be dismantled quickly. "Rocket Mass heater? I dont' know what you're talking about. All I have is these four cinder blocks and a few sticks."
it could heat water for our dishwashing station
it looks simple to make

con's
does it take wet wood?
is it really a rocket mass heater in any serious sense?
cinder blocks will be worn down by the heat eventually


I know hardly anything about RMH's it's been way down the list of things we might do for my community, but any project that says "you can do this in one minute" gets my attention to some degree! Plus I think we actually have cinder blocks lying around.

My thought for now: build one and try it out next time I'm there, nothing to lose, burn it till it collapses and then find a better solution. Unless someone on here has a brilliant better idea, or tells me that's super unsafe. Thanks! (BTW if this was already discussed somewhere and I missed it please do merge/move/delete this post. Thanks!)

This is the video.



I guess it would be a rocket stove, but not a mass heater.

I have to admit, I rather like this video, for the simple reason that up until last night I've totally failed to get my other half onto the idea of rocket stoves, but then I caught him watching this video. I'm discovering that he, like most men I know, much prefer it when they 'discover' things for themselves. I'm biting my tongue now and waiting for him to tell me that we're going to start experimenting - I think he wants to build one to test out the new still.

There's two problems.

The first, you already mentioned. Cinderblocks fall apart in fire. If you're lucky, they fall apart without popping hot pieces of concrete out onto your skin.

The second, though, is that it's not a rocket anything. It's J-shaped, yes, but that's not what makes something a rocket.

People get excited about rockets because they're efficient. (They get all the possible heat out of the wood, instead of leaving half of the potential unused as smoke.)
They're efficient because they're hot. (Above about 1,100F or so, the combustion becomes pretty complete. Everything burns, including the solids that would have floated up as smoke.)
They're hot because they're insulated. You insulate the heat riser (the vertical part of the J) so that instead of dispersing, the heat bounces around inside, heating up the smoke hotter and hotter, and moving the gases faster and faster. That faster movement gives you the whooshing rocket sound that the system is named for.

The J-shape doesn't make it a rocket. The insulation makes it a rocket.

So to put it all together: those cinderblocks aren't insulated. Without insulation, they won't reach extreme temperatures. Without extreme temperatures, they won't burn cleanly and efficiently. A stack of uninsulated cinderblocks is not a rocket stove.

YEs! Excellent discovery! Let us discover things for ourselves and the energy just flows into place!

That's kinda how it was with my housemate, I showed him the rocket mass heater article but then he discovered this thing himself and so he got to be the smart one. Works for me.

I think I might have four pieces'-worth of broken cinder block to cobble together so I could try this at my house actually!

Thanks for the post.

Burra Maluca wrote:This is the video.

I guess it would be a rocket stove, but not a mass heater.

I have to admit, I rather like this video, for the simple reason that up until last night I've totally failed to get my other half onto the idea of rocket stoves, but then I caught him watching this video. I'm discovering that he, like most men I know, much prefer it when they 'discover' things for themselves. I'm biting my tongue now and waiting for him to tell me that we're going to start experimenting - I think he wants to build one to test out the new still.

Great, thanks for the clarification. makes perfect sense. When I get to learning all about rmh's I'll learn a lot more of this stuff, I look forward to it.

Meantime, I guess this can serve two functions, a "let the wookie win" gateway drug to rocket mass heaters, and a way to heat water very temporarily if we have an abundance of pointed sticks (or unpointed sticks) that are reasonably dry and a couple of cinder blocks. Also, it's just good clean pyromanic fun.

Any other ideas of what this could be useful for?

Also good that it only takes a minute + finding your cinderblocks. Maybe I can start making some bone char on the sly here. If my neighbors don't already think I'm a hobo then this will be the tipping point.

My solution for possible cinder block explosion would be wrapping the whole of the thing (except where the flame comes out) in something like chicken wire...I THINK that can take the amount of hear needed.

Wow, a thousand degrees...that is getting sort of close to kiln temperatures! certainly it's plenty hot enough to do a pizza. Hm....the wheels are spinning...

Thanks team!

Mike Cantrell wrote:There's two problems.

The first, you already mentioned. Cinderblocks fall apart in fire. If you're lucky, they fall apart without popping hot pieces of concrete out onto your skin.

The second, though, is that it's not a rocket anything. It's J-shaped, yes, but that's not what makes something a rocket.

People get excited about rockets because they're efficient. (They get all the possible heat out of the wood, instead of leaving half of the potential unused as smoke.)
They're efficient because they're hot. (Above about 1,100F or so, the combustion becomes pretty complete. Everything burns, including the solids that would have floated up as smoke.)
They're hot because they're insulated. You insulate the heat riser (the vertical part of the J) so that instead of dispersing, the heat bounces around inside, heating up the smoke hotter and hotter, and moving the gases faster and faster. That faster movement gives you the whooshing rocket sound that the system is named for.

The J-shape doesn't make it a rocket. The insulation makes it a rocket.

So to put it all together: those cinderblocks aren't insulated. Without insulation, they won't reach extreme temperatures. Without extreme temperatures, they won't burn cleanly and efficiently. A stack of uninsulated cinderblocks is not a rocket stove.

Joshua and Mike : Actually This is a Rocket type, ( though made out of very poor material )- This is the original "Rocket Stove'' exactly as the article states. This is the original
predecessor To the rest of the Family the Pocket Rocket, And the Rocket Mass Heater RMH!

This unit which was created to be a Cook stove, and a replacement for the horribly inefficient 3 rock fires still used by nearly 40% of the third worlds populations, Is the only
one that truly should be called a 'Rocket Stove' ! !!!

If ether of you wants to research the topic a little more you could search for Aprovechio Rocket Stove on U-Tube or aprovecho.org, The unit created here is something that
'might' be serviceable for several days during a grid-type power failure ! Some cob type Rocket cook stoves are 30 + years old !

Hope this is helpful and timely ! Big AL

Thanks, Big Al! That's fabulous information. I'm gonna find me some cinder blocks, I can just feel it!

I'm gonna look it up on L-Tube, the rocket-mass-heater alternative to U-tube...

This one takes more than a minute to make, but not much more. It's what they call a 16 brick rocket stove and it's better than the one above because you can use firebricks. I have one for heating up water for when I'm harvesting chickens.

Thank you!!! I bet you could make that in under a minute if you HUSTLE! hahaha. Wow, every minute I spend on this forum I feel like I'm getting expert consulting help! thank you! I could actually rustle up enough bricks to make this if regular bricks can do it, and if not it's still really useful info my community may be able to use!

Cj Verde wrote:This one takes more than a minute to make, but not much more. It's what they call a 16 brick rocket stove and it's better than the one above because you can use firebricks. I have one for heating up water for when I'm harvesting chickens.

Joshua M. : Regular OLD bricks ! the kind of bricks you are looking for are a soft Brick -the most useful test is to try and write with it on a cement/concrete sidewalk,
or a black top drive, just exactly like it was a large piece of Sidewalk chalk !

The idea here is that dry soft brick will leave a trail of brick dust, a well soaked soft brick will leave more ! ( For building purposes always work with dry Brick ! )

This is where I recommend going to rockettstoves.com, to download a PDF Copy of the 3rd Edition of Rocket Mass Heaters ! Using "the Book '' as a
teaching / reference manual you will save time, money and frustration achieving a working Rocket Mass Heater RMH, and You will be able to come back here
knowing you can talk to your fellow members and use the same terms to Describe the size, shape and orientation of the RMH and its parts ! Good luck and come
back often Big AL !