New to the forum, been reading, still have some questions.

Two questions.

Construction of heat riser/j pipe for 55 gallon steel drum heater.
Not a mass heater but instead an all steel heater for my garage. I have been reading for a couple of weeks now and I just can't figure out it the thickness of the steel pipe really matters or not because everyone uses something different it seems like. I will do eight inch pipe and would like to use at least something 1/16" thick if not maybe 3/32" thick and may be willing or even need to as I need 1/8 inch diameter pipe for another project and not exactly sure yet the thickness I need for that. I'm a welder by trade (factory production mig) and am bound and determined to build this from all steel so don't try to take me into a mass heater. This will just be a heater for the garage as I work on projects in there.

Question two
About the market for mini rocket stove cookers. Like I said I'm a welder. And those mini cookers that go for 120 on ebay I could build for probably less than 15 bucks a piece and am thinking about building a few and trying to sell them. Just wondering what you guys think of that. Would it be an easy buck? And on portable mini cookers, what features do you guys like and what features don't you guys like.

One feature I might add is adjustable legs, cause in survival/camping the ground isn't always level right? Also I could make the cook top height adjustable so you can adjust the distance from the flame to the pot. So yeah some nuts n bolts easily adjustable by hand and you can cook on unlevel ground. What do you think? What features do and don't you guys like about rocket stove cookers?

Jered Jerad : I am afraid that you have missed much of the specifics of How we get the Terrific heat and therefor high efficiencies, in the rocket stove. Instead of soaking up
the heat and just re-radiateing that energy off of the mass of the stove, we use materials that are slow absorbers of heat energy,and high in emissivity, which means that
the materials we use are not only insulating, but that their surfaces re-radiate the heat energy back into the Heat Tunnel/Combustion Zone !, In spite of Many You-Tube Videos
showing near look-alike Rocket clones made out of steel, they do not stand up to the terrifically high temperatures produced by a well made rocket, most fail within a single
heating season. Retrofitting insulation into a metal RMH Clone will make the Combustion zone so small as to make a toy out of these Frankenstein Builds !

Simply Put, show me a U-Tube Video of a Steel Rocket Clone, that is Just two years old that the proud owner is still this month defending against all negative comments, and
says nothing about a rebuild ! Their are lots of designs of Franken-clones out there, but ether all comments are blocked, or the builder/owner has gotten dissatisfied with his
toy, and is off chasing another shinny bauble !

Try some builds of your own, abuse them, and see how well they hold up ! The Rocket (Cooking ) Stoves even more so, Google Aprovecho Stove Design, don't be in a hurry
to put your name on something that will come back to haunt you ! For the Good of the Crafts !

Think like Fire, Flow Like a Gas, Don't Be The Marshmallow ! As always, your comments and questions are solicited and are welcome, PYRO - Logically BIG AL

I understand the purpose of the mass. But I also understand that without the mass rocket stove cookers can boil a large pot with little wood. It was my understanding that steel rocket stove heaters were a step up from wood stoves and a step down from rocket mass heaters.

So what you are saying though that I would be better off buying a cast iron wood stove?

A rocket mass heater is just absolutely out of the question at this residence. If I would really be better off converting my 55 gallon drum to a wood stove VS a steel rocket heater then that's what I will do cause I barely have the space for that even. Still trying to figure out where I'm going to put what I have now.

As far as the mini rocket cookers, I built an experimental one from scrap metal in my garage. Looks like crap but is solid. I used straight perlite as insulation. I was impressed with what that did. I'm going to cut it up and throw it out this weekend. It's just that ugly. But hey didn't cost me a penny to build. Just wanted to experiment with one and see if they were good before I put more time and effort into excellent craftsmanship. I'll post the video, dont laugh though. The stove looks like complete crap cause it was built in a hurry from my scrap steel pile. I didn't want to put much time and effort into one if they weren't what they were cracked up to be.

So you said that they usually fail, in what way do they fail? And honestly with something like this where there isn't a lot of people talking about the failures and success's then I surely do expect many to fail. Hence why I cam here. Does the heat riser and j tube need to be really thick? Do I need to make the heat riser and j tube from a different material?

j tube and heatriser out of perlite/clay mixture iron can be used as a mold. It will burn away in no time even 1" thick + the metal will draw energy from the hottest points
This will lead to poorer combustion = polution of your system
you can use brick too , old red brick tends to do better against heatchock and insulate the heck out off it when using brick

I used a stovepipe for my first testmodel it burnt away in 30 fires so that's why metal will fail even stainless ,that last one may last 1 or 2 heating seasons but will fail.
kind regards karl

Ok so what you are saying is that steel simply cant handle the head of the interior of the combustion chamber. I'm not against using other materials, I just don't have much space. Can I encase the bricks used for the j tube in steel? And are you saying that the thin sheet these guys (see video) used to encased the perlite clay in will all burn away?



Does the steel in the mini rocket cookers hold up because it doesn't reach as high of temps?

would a design like this work for some sort of a low mass heater? And what would be the durability of something like this? I want maximum portability. Can I drop it on its side? If not that's ok, just want to know what I'm working with here.

you can use perlite but make shure that its fix whit clay the clay can whitstand the heat so can the perlite( that is rock expanded under heat )you can use a cardboard sonotube as a iner mold . Burn it out and you have your riser afther the riser the temperatures go douwn a lot there you can use metal no probs

make the riser thicker than in your drawing so the insulation can do it's work

Jared Jerad : There is an old saying, to a man with a hammer, all problems are nails! This is in no way a put down of you, your welding skills, or steel when it is used
for the right job !

There is so much Crap out There in You-Tube Land that it is almost impossible to find the few honest people who are reporting major failures ! We have a few posted
here !

It is better to use stacked bricks to make a Feed Tube and Burn Tunnel, and then with the very lightest and cheapest cold air return ductwork, make a sandwich of
clay and perlite or clay and vermiculite, or clay and sawdust* so that your duct work on the inside and the outside become sacrificial forms to create the Heat Riser !

Take your sketch, call the diameter of the inside wall 6'' the thickness of the clay and perlite,2'' and the inside diameter of the Outside pipe 10'' . 2'' + 6" + 2" = 10''
And you have made a rocket stove that will last you for many heating seasons. Clay and Vermiculite would need to be 2 Xs as thick = 12''

In your picture you also have metal clad insulation down to a point, actually that point should be where the Entire Heat Riser sets on top of the brick of the Burn Tunnel
/Combustion Chamber, this is also the First failure point for the Heat Riser, even Stainless steel will fail at that point!

The Shape flowing the Flame Front out of the Burn tunnel should be more like an elbow and not the " T " as your sketch has it (this is a skill i have not mastered!! )

Offer to buy a cold beer for a Fossil Fuel Fired Forced-air Furnace Technician, and promise to listen and you will get an earful of 'Failed heat exchangers I have Known'
stories, its not the lining that fails its the carbonized steel ! ( any failure of, or damage to the insulation from say a ham-handed furnace tech sticking a vacuum cleaner
inside the combustion chamber, will just burn up the steel that much faster)

Not to worry the ductile steel in todays 55 gal drums is still heavier than the steel in the Heat Exchangers of commercially available Furnaces, That is What you 55 gal
drum is, a heat exchanger and it is down stream from the freaky high temps found in the Heat Riser !

Just a simple plea for a little respect for the RMHs Thermal Mass, you are looking at it as though it was something that removed living space, something you were going
to bang your shins on for the next 20 yrs, properly built, and located in the very heart of your home, it becomes a wonderfully warm sculpted piece of built-in-furniture
that will become a treasured member of your Family ! For the Good Of the Craft ! As always, your comments and questions are solicited and are Welcome Big AL !

* I was getting a little carried away here ,this can be and has been done, but will be a little to delicate for ham-handed people with vacuums and wire brushes ! A.L.

Ok so long story short my new drawing thanks to advice from you guys should work? Just make the T an elbow (90 degrees not a curve) and its good to go? So I do use thin cheap steel on most of the steel like in my drawing but it will all burn up quickly? How many burns before it is all gone? And I MAY (I stress the word may) do some sort of portable mass heater live in the video but only like two feet wide and four feet long. Not sure yet what I want to do. This heater will be heating a two car attatched garage. I know that the mass means more efficiency but it also means takes longer to put off heat. I can see myself wanting to quickly heat the garage often. Then again I know that if I do some more mass that will give me my best shot of setting a fire before bed and waking up to a warm garage. I'll want that garage warm 24/7. What do you think?

And yeah I do want a nice built in rmh heater eventually. But I'm not going to settle down for a decade give or take so.

Jared Jarad : Yes-Kinda, Its time that you learn about the need to keep a Constant Cross Sectional Area, and how to determine it based mostly on the amount of heat
actually needed.

For a first build with Good fire bricks for the Feed Tube and Burn Tunnel, and a round Heat Riser, your first build should stick with the formula and be no smaller
than 6'' and no bigger than 8'' ( which you would not want in a two car garage anyway !)

Also there is a pretty clearly defined ratio, the depth of the Feed Tube,(1st build 16-ish inches) is 1/3rd the height of the Heat Riser 48'' minimum, and the length of the
burn tunnel should be 24-ish inches 1/2 of the height of the Heat Riser !

Good fire bricks, 9'' X 4.5'' x 2.5'' weight 28 to 30 ounces, Not the 7 pound ones, or use old soft red, red orange 100 year old bricks !

Brace yourself, this is where I send you to rocketstoves.com for your $15.00 PDF Copy of Evans' and Jackson's Great book, 'Rocket Mass Heaters', there is
no other book in any language with more Rocket Mass Heater Family information ! With over ~100,000~ RMHs built world wide most of them have been made following
''The Book'' ! 95% of all the first builds (that Worked) came directly from ''The Book'' !

I also want to give you a peak at your host here at Permies.com and our sister site richsiol.com Paul Wheaton, you can get a glimpse of where his head is at
here at - ' www.thesurvivalpodcast.com/wheaton-rocket-heating '

He is a deep thinker, very sure of himself, and a perfect man for what he is trying to do - while he is holding forth remember that these two guys are a couple thousand
miles apart and both of them 'feed off of each other' though they have not had a face to face in years, and 2 months ago Paul thought that an all steel feed tube would hold
up better than bricks and Cob !