compact 6" RMH hybrid with cook top and dutch oven

I've recently designed and started fabricating my first RMH. It looks like a familiar traditional steel rocket stove, but mine is 6" in the primary riser, 5" square tube for the feed and burn chamber, and I've filled the chassis up with a mix of 40% perlite and 60% cumston mixed HD concrete and high temp mortar. I tinker with it in my spare time, so I'm not making huge progress daily, but I am making progress. I tested the J-tube core earlier in the development process and I had great success and zero smoke with the core. This is my stove and my personal design. I made about 15 designs before I went to work, so if you don't like it, keep the opinion to yourself please. Feel free to use or improve upon my design, but keep opinions and input to the positive spectrum please and thanks.

Some more photos of develpoment in my messy dirt-floored shop. I call my stove design EMBER (Eco-Mass-Bio-Efficient-Rocket)

Filling her up with DIY firebrick refractory concrete. About 30% of mix is 6000 psi fiber enforced concrete, another approximate 30% of mix is high temp mason mortar, and approximate remaining 40% of DIY mix is perlite.

You haven't been told that metal is doomed yet?

There's nothing like traditional steel rocket mass heaters. If working properly, metal rockets will fail in short order.

Metal rockets are just POS you see on youtube.

I am interested in what help the vortex generator adds. Having a window where you can take pictures and video of it in operation would be great. Also, using the window over time to watch for deterioration of the vortex generator would either confirm (with good evidence) just how much metal sucks for RMHs or that it is OK to use when done right. [Of course, even if the metal fails after one season that might be OK if you can easily replace or fix it cheaply.]

Ron Helwig wrote:[Of course, even if the metal fails after one season that might be OK if you can easily replace or fix it cheaply.]

But... quite some time before the tunnel and/or riser fails the metal's deformation will disturb the workings. It is like holding a little umbrella in the gas stream where smooth walls are required. Even stainless steel will corrode away over time in there.

And moreover, the failure will likely take place when in depth of winter the stove is pushed hardest. In short: it won't fail after a season but right in the middle of it.

John McDoodle : Mad welding skills ! Welcome to Permies.com and a Big Welcome to the Rocket and Wood stoves Forum threads !


In the Early days of "Nascar'' The rule was ''Run what you Brung'' ! This ensured a large field of cars, and if a post-ran inspection disqualified a few cars -

at least the fans got to see some good racing ! As a first attempt it looks good and will be able to keep up with the field for most of a race, eventually you

Will start to show the problems that your fellow members have mentioned ! Depending on location you are probably going to need a back up plan and your

Post Race heating season teardown will be a great learning experience !- For those reasons already mentioned !

Usually I try to get in an early warning about the Huge amount of Stinking Crap Videos published on You-Tube ! This is more for other Future Rocketeers ,

rather than you!

Stick around and watch these pages, And remember we all started where you are now -! Big AL

Thanks for the constructive criticizim and input guys... If my steel prematurely burns out, which I have never encountered or even heard of, I will have no problem, because my stove will still have a huge concrete core. It will still be in the same shape as it is now if the steel deteriorates. Something I never concerned myself with, but if it does, I will simply remove the removable top, and insert a new riser into my concrete cast core. My acuual burn chamber is 8mm thick which is the only part that might fall off if it deteriorates. How long would that take? 5/16" 8mm is very thick, and I'm confident that part will last for years to come. I'm a scrap metal worker. So I know a little bit about my materials. I will let YOU guys know how long my parts last, since you can't really tell me how long my parts will last. I appreciate any info or any concerns you have so keep the questions coming!

I know the thin metal that has been used by people using barrels and cans doesn't last long, but I don't use thin materials, and my steel is either incased in cast refractory concrete or thick enough to evenly disperse the heat in the very few areas where it is not incased in refractory concrete

John McDoodle wrote:if you don't like it, keep the opinion to yourself please.

Satamax Antone wrote: You haven't been told that metal is doomed yet?

Peter van den Berg wrote:quite some time before the tunnel and/or riser fails the metal's deformation will disturb the workings.

John McDoodle wrote: If my steel prematurely burns out, which I have never... even heard of, I will have no problem

John McDoodle wrote: I will let YOU guys know how long my parts last, since you can't really tell me how long my parts will last.

Is this going to be a main heat source for your home? Please let us know in the spring how it worked out!

Ron Helwig: yes there is a glass fireplace view window included in my pre-build dedign drawings. Its basically going to be at the bottom of the feed tube, where the primary ash clean-out is. Also the 1/4 diamond plate lid is removable, which helps me to monitor the inside of the stove, and clean out beyond the primary riser


Anyone who is sceptical or judgemental of physics that you don't even understand, just know that I'm confident that the steel and concrete will last for years, if not decades. I've seen people get thin walled stove pipes red hot for seasons, months a a time, so I know my design will last several years. Also if anyone disagrees, just research ZAUG stove company. They have been making and selling these types of designs for years, same with dragon stove company. So if you want to tell them nonsense about their stoves degrading, which they don't, email them first. lol.

"Big Al" Allan Lumley: thanks but I had the J tube professionally welded. The welder used his arc welder for the J tube core because my material is so thick and dense. An arc welder would melt right through a barrel, but I don't use barrels and all my materials are at least 3/16" thick. The hottest part of the stove is 5/16 (8mm) thick and the removable top is 1/4". I like how you compared the old nascar days to the develpoment process lol. I know I'm a new member here, but I love physics and science and mostly I love creating something useful from recycled materials, while greatly reducing carbon footprints and global wood consumption.

I found a lot of inspiration with secondary air and vortex generation from Ppotty on youtube, I also found a lot of inspiration in our global forests being raped, and I found design inspiration between the Dragon stove company and the Zaug stove company, who both also start with steel, and fill with refractory firebrick concrete, like my design.

John McDoodle hey permies forum member in common i respect your heart and your will to do even if people say you cant... i really do respect that. there are facts you must also respect and those are the facts of RMH temps. if your RMH does indeed meet or exceed the high temps a RMH owners usually desires to heat a normal size home i can assure you that those temp will deteriorate steel and in quick order and i am not joking in the slightest. the 6" metal duct i had in my box although extremely thin compared to your box was incinerated in one burn. no joke, RMH are not the normal "firestove" RMH can melt glass, steel and cause portland concrete to explode into ity bity pieces.

i wish you the best and hope that if you do indeed keep your box the way it is, i hope you designed it to stay in the sub 900 degree temps and not go above that or it will eventually spell trouble.

great looking stove though.

keep in mind a well made RMH can exceed 2000+ degrees. look up all the things that can melt at 2000+ degrees. even clay chimney liners melt at 2000+ degrees.

This thing will look a whole lot better when its complete. Lol.

I agree, thin metal and ducting won't last long, as you learned the hard way. That's why I don't risk using those materials. I actually tested my entire stove today, not just the core, and it worked very well. My step father loves it and he wants to build one now. Try using thicker and more dense materials and you might have better luck. I understand your sceptical because of what happened to you, but my design is thick and solid. Like a traditional wood stove, which I have also had glowing red lol. The woodstove did not deteriorate, and neither did my rocket, and I've fired the core and the entire stove multiple times.

I want to challenge the haters and sceptics to show me your catistrophic fauilures, preferably a video. Either you designed it wrong, or you are using the wrong materials if you have catistrophic failures. I will let you know how mine works as I further the development, until then, show me your 3/16" or thicker steel deteriorating, I want to see it with my own eyes. Also until then, check out the proven Zaug stove company, they use very similar materials, thicknesses and designs, problem free, like mine

http://www.zaugstoves.com/wordpress/specs/


Perhaps before anyone embarrasses themselves by saying that steel is doomed or steel doesn't work, try doing some research or physiscs calculations. At the very least read the entire thread. I don't enjoy making people look wrong or stupid, or repeating myself. I just want to share a great DIY cheap design which is very efficient. At least consider igoring my design and look at the Zaug stove or the Dragon stove companies. Tested, proven, possibly even guaranteed. So you can email these companies and criticize them and their proven tested designs, before anyone embarrasses themselves by saying "steel is doomed" or it won't work, or it won't last. Don't ignore the facts and physics. It works, its been donethats ignorance. People are making money and thriving companies on this type of design!


http://www.zaugstoves.com/wordpress/specs/

John, i'm not embarassing myself, when i say "metal is doomed" i use metal in my stoves. But not for the core, as i have learned the hard way.



You see this thing? It's hydraulic tubing About 6.5 or 7mm thick.

By the end of the 32 hours burns, it was like puff pastry in the elbow. The metal was about 1 inch thick inside, because of the spalling, and the cyclonic rocket was unusable. The gas bottle started sagging under it's own weight. That's metal heated to the white. You obviously see the spalling. That's not on the oxygen rich side, which creates the spalling usualy. If you don't trust me. Carry on. But please, don't tell me afterwards that your contraption works wonders and such. I know that if you reach the proper temps for a rocket stove of any kind to work properly, steel won't hold.


I can even tell you that i'm killing refractories too. I've had the bricks and refractory tubing in another stove, glowing orange. That's more than 900C°, yep celcius, not farenheit. How long do you think steel could survive at that kind of temp. Seemingly, a rocket can reach 1200C° on a regular basis.

I should have cut that elbow on the cyclonic rocket, to show the world what a rocket can do to metal. But i threw it in the skip before thinking about it.

F Styles:

Yes of coures it is designed to operate below 900 degrees. I'd hate to see ANY rocket stove achieve anything higher than that! Lmao. That indeed would be a catostrophic issue lol. But I don't think ANYONE will ever run into 1000 degree teritory. That's just craziness... If your rocket produces surfaces that are above 900 degrees, you might have to re-design for residential use, because that sounds like forge temps, not residntial heater temps. My stove is designed to cook on and has a removable dutch oven, if any surface was 900 degrees, I'd burn my food! Lmao. That's just not practical at all!

http://www.zaugstoves.com/wordpress/specs/

Satamax antone:

Wholy sh#t, that's crazy. Care to explain what's going on in the photo? Was that insulated or inside of something? Any more photos? The concrete in my stove will be the major difference, absorbing the heat as a mass, and evenly distributing at the same time. If I encounter anything like that, or if my riser fails, I will remove my removable lid, and insert a stainless steel riser... That must be a design flaw or heavily insulated, as mine is not...

John McDoodle wrote:Satamax antone:

Wholy sh#t, that's crazy. Care to explain what's going on in the photo? Was that insulated or inside of something? Any more photos? The concrete in my stove will be the major difference, absorbing the heat as a mass, and evenly distributing at the same time. If I encounter anything like that, or if my riser fails, I will remove my removable lid, and insert a stainless steel riser... That must be a design flaw or heavily insulated, as mine is not...

I was editing while you posted.

The whole thing was in vermiculite. And for a proper rocket to work, you need insulation. Check the explanation above and the pics. If you have mass around the core, that will sink the heat needed for it to work.

You can use metal to form a poured refractory core. And leave it in place untill it burns. But for that, you better use thin stuff, so it doesn't crack your core. The only thing is, you haven't gotten how rockets work yet. I will pass the push pull theory, as i don't believe in it much. What a rocket stove does, is burning wood at a very high temperature. Mixing the gases throughoutly, via the two elbows, or a port. There's several versions now. In an insulated environement. So you can reach temps above the dioxin formation temps for example. It burns all hydrocarbons, pretty much. And after, only after, you gather the heat. And they are pretty efficient at that too.

One word of caution, if you smell a faint acrid smell a bit like bleach smelled from far away, in your exhaust, stop sniffing, and carefull, you might be just at the end of the dioxin forming temperature scale, and you could poison yourself and neighbors without knowing it, if you burn plastic in there. That smell means you are under the 900C° barrier usualy. Above that, you're good to go, there won't be much left in term of hydrocarbons.

Satamax Antone:

Good lord. Mine won't get get as hot because 60% of my "insulative firebrick" mass is very conductive. I don't find it to be "safe" for any residential heater to get that hot...

What is your opinion on the Zaug stove and their 3 year warrantee.?

I've read some threads online and ernie (I think he wrote a book on rocket stoves) says many times in multiple threads, that these stoves are only meant to run long enough to charge up the thermal battery (mass). Basically heat it up and let it radiate for hours... So that is what I designed mine to do... But more compact. You ran yours for 32 hours?? Being that yours was very well insulated in vermiculite and run that long, I can definately see why it got so hot and had a forge-type meltdown lol. My mass is only 40% insulative, and 60 conductive... Possibly 75% conductive if you include the 200 lbs of steel as a mass also...

Were you using that as a forge? Forced induction using a fan/electricity? Any photos of the complete stove, air input while operating, or complete while operating?

John, a rocket, bellow 800/900C° is not functioning properly. And the core needs to be insulated. In early Ianto Evans's build, it was done with mud and ashes. So i doubt the high temps required were reached that fast. Let say a split firebrick and vermiculite board core can reach full burning temperature in under 5 minutes. If well insulated. A cob core takes may be half an hour. And up to that point, it's nowhere near as efficient as claimed. There, i'm talking about internal temperatures. The temperature of the barrel and mass are way lower. For example, on my latest batch rocket build, i reach 180C° on the equivalent of the barrel. Mass is never above 35C°.
That's perfectly safe for house heating.


On the cyclonic rocket above, i burned it may be 4 hours at a time. That's rather usual for a J tube rocket. I didn't burn it everyday. And it lasted may be 2 months. It was a workshop heater, fed only scrap wood.

The OP may never be swayed. This is for everyone else.

I watched a YouTube video where a guy had a rocket with maybe a 3 foot riser. He demonstrated how it could be used for blacksmithing. I've done a little blacksmithing. If left in the fire for even 30 seconds too long, the metal can deform. If a duct were to collapse during a hot burn, you'd have a raging fire with no chimney. Not a "check it out at the end of the season" type of event.

The Zaug website is vague about their exact construction, except that the feed and early combustion zones are heavy steel, and there is significant insulation as the flow transitions to the riser. It may be possible that the steel parts conduct away enough heat that those parts will not be damaged, and if the internal parts are well enough insulated, high temperatures and efficient combustion may occur.

Dragon Heaters makes their combustion cores entirely of refractory materials. Only the feed tube insert is made of steel, to conduct/radiate heat away from the upper feed and improve burning characteristics.

You say that you have deliberately constructed your heater with more conductive, massive material surrounding the riser; this will draw heat away from the combustion zone and reduce the likelihood of full combustion that makes the rocket heater so efficient. It will also by reducing the maximum internal temperatures prolong the life of your unit.

To be very clear, nearly all RMH builders are not trying to produce superhot external temperatures, only internal temperatures that promote complete combustion. We then moderate the temperatures for proper use in the external environment, just like you are doing.

We can refrain from belittling anyone's efforts, but that does not mean we should refrain from pointing out differences that would reduce the effectiveness of an approach, or correcting misunderstandings wherever they originate.

John McDoodle wrote:I agree, thin metal and ducting won't last long, as you learned the hard way. That's why I don't risk using those materials. I actually tested my entire stove today, not just the core, and it worked very well.

John i did not use the 6'' thin metal duct as my system core. it was only used to build the firebrick heat riser and core around it and it was meant to burn up as a sacrificial inner support so the firebrick had a form to dry around. my firebrick system works quite well and out performs most RMH i have seen. i can even put 10''x18'' full size logs in my RMH and have it burn for 6-8 hours. i did it all very inexpensively and its also on wheels so i can remove or move the system to clean or to use it in other places. i love my set up. your welcome to check it out.

John McDoodle wrote:F Styles:

Yes of coures it is designed to operate below 900 degrees. I'd hate to see ANY rocket stove achieve anything higher than that! Lmao. That indeed would be a catostrophic issue lol. But I don't think ANYONE will ever run into 1000 degree teritory. That's just craziness... If your rocket produces surfaces that are above 900 degrees, you might have to re-design for residential use, because that sounds like forge temps, not residntial heater temps. My stove is designed to cook on and has a removable dutch oven, if any surface was 900 degrees, I'd burn my food! Lmao. That's just not practical at all!

http://www.zaugstoves.com/wordpress/specs/

John... my forum member in common i need to share with you that your post is in the rocket stove section... a true rocket stove is not a true rocket stove unless it gets close to 2000 degrees F. posting your stove and i mean "conventional stove" in the Rocket stove section is like taking a stock F150 truck to the INDY 500 to race. sub 900 degrees is reachable in a "conventional stove" and without reaching those temps it defeats the purpose of a rocket stove. what you built is good looking and it may be what you are after but i can tell you a rocket stove is not a rocket stove at 900 degrees. it may look like a rocket stove... but it quacks like a duck and not a dragon.

my stove and others will show you that a true rocket stove should and will get close to 2000 degrees. yes many people can Kiln clay and forge steel its that hot. "LMAO" Rocket stove temps are no laughing matter. it gets that hot. i challenge you to insulate your "heat riser" and lets see how long it lasts.

John, i was thinking of you this late afternoon. Sitting with a friend in front of the last batch rocket i've built, and showing him the cracks in the refractory heat riser looking like lava. And after, re feeding it before leaving the workshop, and the whole heat riser was glowing orange. Opening the top door at the end of the heat riser, and seeing no smoke at all, and not the faintest smell of anything.

If you like your thing, ney bother. But please, report back in april or may. And we'll see what you have to say about the contraption you've built.

Here's a warm-up photo. It was too cold for my liking, for the concrete to set, so I decided to warm it up slightly lol

Another photo

Erie Wisner has posted in a few places concerning the testing of new designs. He looks at many new designs and has come up with many of his own, but he never recommends or endorses a design until it has been used successfully for a complete heating season, without developing problems. That's by no means an exact quote, but I think I got the gist of it.

The best stove I could imagine 5 years ago, is not the same as the best one I have in my head now. Most of what I've learned, has come from innovators who do good forensic reports after they have lived with a system for a long time.

Dale Hodgins:

That's understandable and makes perfect sense.

For now I'm sharing my design concept and progress in my development, so far so good. I'm actually in the shop on my mobile phone right now working on the riser, I'm changing my outside diameter of the cast riser from 8" in my plan, to now 10". So inside riser diameter is still 6" steel, outside diameter is going to be upgraded to 10". I was just looking at the actual stove and I think 1" cast riser may not be very strong. So it should be about 2" thick after my slight upgrade/change in design

maybe if you are desiring a metal core i have never heard of anyone using tungsten. get a hold of a tungsten lined riser and youll be in good shape. 6,191°F melting point. tungsten pipe

tungsten pipe 2

you can easily get a service use from a tungsten alloy up to 1800+ degrees F which would put you in the perfect temp for RMH.

John McDoodle : O. K., a little Physics History! After Hydrogen was 1st cooled to a State of Liquefaction- It was quickly noted that its containers all emptied out

Faster than was expected. It was commonly believed that the Liquid Hydrogen (in a glass container and stoppered ) was wicking itself up the walls of the container

then flowing around the stopper and down the outside of the glass . This Interpretation of observed phenomena held for a long time!


It was eventually proven that the diatomic hydrogen molecules ( 2 Atoms of Hydrogen ) were actually flowing out Through the nano-sized pore spaces in the glass!


This observation is critical to the understanding of " High Temperature Hydrogen Attack" And its effects on all forms of steel ( less with Stainless Steel ).


At the High Temperatures Your Fellow members are telling you are common in a Well made Rocket Mass Heaters RMHs " Combustion Core " The Most common

appearance of Hydrogen is as a single Atom - Monatomic Hydrogen; as such This incredibly Slippery Atom of Hydrogen, with a great 'potential energy' due to its

high temperature, easily finds the pore spaces ( mostly due to Trace impurities ) in the Crystalline matrix. There it readily combines with another Hydrogen Atom

and an Atom of Oxygen to produce a molecule of Water H2O - Specifically ''Steam Embrittlement !''


Separately, several Monatomic Hydrogen Atoms can enter other Pore Spaces and combine with a Carbon Atom to make a molecule of Methane, this new molecule

can also Disrupt the crystalline structure of most Steels and Iron !


As you say, a rigid and intact Heat Riser should remain long after the Metal within the ''Combustion Zone '' fails. It is important that No Portland Type Cement be used

within this location, and the single most important requirement for a Heat Riser is its ability to be Refractory, or not only be non heat absorbing but actively reflecting

that heat back into the Combustion Core!

You are a good ''seasoning'' for your Fellow Members, However, as a group or individually, they have much to share with you. For the good of the Crafts ! Big AL

The following are our most widely used alloys in manufacturing industry, their major
characteristics, temperature limits and approximate Brinell hardness (HB).

CARBON STEEL
Material frequently used in manufacturing. Due to its low resistance
to corrosion it should not be used in water, diluted acids or saline solutions. It may be used in some
alkalis and in some concentrated acids. Temperature limit 900° F (500° C).
Approximate Hardness: 90 to 120 HB.

STAINLESS STEEL AISI 304
Alloy with 18% Cr and 8% Ni is the material most used in the manufacturing of industry due
to its excellent resistance to corrosion, low cost and availability in the market. Its maximum operating
temperature is 1400° F (760° C). Due to Stress and Intergranular Corrosion, its continuous service
temperature is limited to 790° F (420° C).
Approximate Hardness: 160 HB.

STAINLESS STEEL AISI 304L
It has the same resistance to corrosion as the AISI 304. Since its Carbon content is limited to 0.03%,
it has less Intergranular Carbon precipitation and therefore less Intergranular Corrosion. Its
operational limit for continuous service is 1400° F (760° C). It is susceptible to Stress Corrosion.
Approximate Hardness: 160 HB and in some cases,140 HB.

STAINLESS STEEL AISI 316
This alloy with 18% Ni, 13% Cr and 2% Mo, offers excellent resistance to corrosion. It can have
carbonate precipitation at temperatures between 860° F (460° C) and 1650° F (900° C), under severe
corrosion conditions. Maximum recommended temperature for continuous service is 1400° F (760 C).
Approximate Hardness: 160 HB.

STAINLESS STEEL AISI 316L
It has the same chemical composition as the AISI 316 but its Carbon content is limited to 0.03%,
which inhibits the Intergranular Carbon precipitation and consequently, the Intergranular Corrosion.
The maximum service temperature is 1400° F (760° C).
Approximate Hardness: 160 HB.

STAINLESS STEEL AISI 321
Austenitic stainless steel alloy with 18% Cr and 10% Ni stabilized with Ti, which reduces the
Intergranular Carbon precipitation and also the Intergranular Corrosion. It can be used in
temperatures up to 1500°F (815°C).
Approximate Hardness: 160 HB.

STAINLESS STEEL AISI 347
Alloy similar to the AISI 304 stabilized with Cb and Ta to reduce
carbonate precipitation and
Intergranular Corrosion. It is subject to
Stress Corrosion. Has good performance in high temperature
corrosive
service. Maximum temperature: 1550° F (815° C).
Approximate Hardness:
160 HB.

MONEL
Alloy with 67%
Ni and 30% Cu, it offers excellent resistance to the majority of acids and
alkalis,
except to extremely oxidant acids. Subject to stress corrosion
and therefore should not be used in the
presence of fluorine
-
silicon acid
and Mercury. In combination with PTFE, it is used frequently in spiral
wound gaskets for severe corrosion services, such as Hydrofluoric acid.
Operating maximum
temperature: 1500° F (815° C).
Approximate Hardness:
95 HB.

NICKEL
200
Alloy with 99% Ni, offers
great resistance to caustic solutions, even thought it does not have the
same
global resistance of Monel. It is also used in spiral wound and
jacketed gaskets for special
applications. Maximum operating temperature:
1400 F (760° C).
Approximate Hardness: 110 HB.

COPPER
Material often used in small dimension gaskets, where
the maximum seating stress is limited.
Maximum operating temperature: 500°
F (260° C).
Approximate Hardness: 80 HB.

ALUMINUM
Due to its excellent resistance to corrosion and easy
handling it is very often used in manufacturing
gaskets. Maximum service
temperature: 860° F (460° C).
Approximate Hardness: 35 HB.

INCONEL
Alloy with 77% Ni, 15% Cr and 7% Fe, it has excellent
corrosion resistance from cryogenic to high
temperatures. Temperature
limit: 2000° F (1100° C).
Approximate Hardness: 150 HB.

TITANIUM
Metal with excellent corrosion properties in elevated
temperatures, oxidant service, Nitric acid and
caustic solutions.
Temperature limit: 2000° F (1100° C).
Approximate Hardness: 215
HB

304L stainless steel has a max service operating temp of 1400 degrees F and if you plan to keep your temps there or lower you may have your self a nice steel RMH can be found here for less than 200 for a 24'' riser section. 304L stainless steel

Maybe titanium or nickel would be a good substitute if my riser prematurely fails, however I've designed my stove very similar to the Zaug stove, which has a 3 years warrantee, and mine has less insulative value and a built in mass, so mine will likely last longer than a Zaug.

Furthermore, my design is a HYBRID, rocket style, shape, whatever you want to call it, it may not be a true rocket by your standards, but it is by the Zaug companies standards.

I want something practical that I can use in my 18x18 underground tiny home. (Which is also a HYBRID home). I want to cook food on it, I want it to last, and I don't want it to melt down, and since I'm already procucing clean emissions (zero smoke) I feel that my design does not require any further insualting. It works, I plan on using it in my tiny dwelling if I finish it in good time. So I can let you know if it outperforms a zaug, or outlasts, or how it works for me in general for my HYBRID multi-use purpose.

304L stainless steel has a max service operating temp of 1400 degrees F and if you plan to keep your temps there or lower you may have your self a nice steel RMH can be found here for less than 200 for a 24'' riser section. 304L stainless steel

you can purchase 316L steel pipe there also which is slightly stronger.

if you really liked this stove you built and wanted to increase its life span you may be able to get more life out of it by lining it with nickle sheet/plate.
nickle sheet/plate

most RMH enthusiasts will tell you not to use stainless steel also because they say it will also break down but what most of them dont understand there are many grades of stainless steel ranging from 700 to 1600 degree F operating ranges. most people acquire the low cheap grade of stainless and get them self into trouble and there fore lumped all stainless steel in the do not use category.

i would still love to see someone use the tungsten alloy idea i mentioned.