How To Make A Cobb Rocket Stove Water Heater 

Great project! I also really appreciated not having background music with everything. It had a good balance.

That's awesome!

I stumbled upon you and am so happy 😃 I love it! Thank you I look forward to seeing more

The hot water should reenter lower in the bucket. Here the hot water heats in the air... Not very efficient to heat the whole water ;-) Thank you for the video.

To avoid kinking it - plug one end fill with water and set it into your deep freezer .

next time fill the copper with salt or sugar and go up higher with a narrower coil and get more efficiency out of it. Having flames come out the top is not efficient

Love your videos.

Thank you for your videos, my 11 yr old grandson and I are going to be making a rocket stove!

Use salt for filler to bend it. Easier to get out being water soluble.

You wasted so much hot gases and energy from short chimney, you must utilize chimney design either make it longer and longer copper coil or add extra heat absorbing material to the chimney.

You should stretch out the coil slightly and mount it inside a wire tube so the clay is not in contact with the copper tube. If there’s a slight space between the coils it should be more effective. You can even incorporate it in the side walls of the fire pit as well the lower it is the better. You should make a damper to slow down the burn. It burns too fast so you use more fuel. That would also be good for a home made hot tub in the yard. In summer I do all my cooking on one make of recycled bricks.

To prevent kinks in your copper pipe you could try bending it around a piece of schedule 40 pvc or other pipe in the size that you want the coil to be. The trick is to keep the copper pipe close to the pipe used for the shaping and bend it a little at a time. It makes a perfect uniform coil without kinks if done right.

You can also fill the soft copper with water, then freeze it. To prevent kinkage.

Pro Tip: Another way to curl copper tube is to fill it with water and put it in a freezer, the ice will support the tube wall which prevents kinking.

Bend your pipe around your pvc chimney form.

Tom a couple questions. How long did it take to heat the 5 gallons of water and how much fuel was used to get it hot? Great design really like the concept. it got me thinking of making one of my own.

Thank you for the video, i'm facinated by rocket and similar wood-burning stoves. I am particularly attracted to the heat efficiency and low-pollution achievable which I understand comes from having a very high temperature extended chimney above the fire to complete the burn. Having a pipe for water heating is attractive but being so close to the inside of the chimney, I think this must negate the high temp chimney objective. I presume this why we often see a cover over the chimney, forcing the exhaust back down and exhausting at the base. The area between the chimney and the cover is the area where heat could be harvested with the coil to heat water, without risking the "hot chimney" principle. Any thoughts - have you tried this sort of design ?

Handmade rocket stove is good! In Japan, where I live, it has become cold in the fall. I use a clock-type stove. Warm tired body by boiling water and drinking coffee during breaks in farm work☕️

WHAT ABOUT A COB ROCKET STOVE OVEN / PIZZA OVEN??? I'D LOVE TO SEE THAT

nicely build,i have made something similar for the swimming pool

Instead of placing coil inside the near the fire. I would have encased the coil inside the mud. Still getting the heat from inside but would have given you a much larger coil ring for more water to be heated.

You could've used your pvc as a form for wrapping the copper coil. Cool video, thanks man!

The “thermal” pump works better than I thought it would. Thanks for the education!

Use a metal bucket instead of plastic & place it 2/3 inches above the chimney? Max heat output capacity, just a thought 😸

Sped-up construction noises is my new favorite sound!

Great video. As you like challenge look about having a better heat exchange. Heating water with fire and copper inside and then cold water thru. Look at geoff Lawton rocket stove heating water first version you will love it.

aren´t you wasting a lot of heat power whit that open flame coming out of the chimney? You can use that fire! I think that It coudl be better if you place the pot over the flame and kepp also using The copper pipe... maybe I´ll test it! Good job, friend!

I'm working on making an animated 'explainer' video to share my ideas about off-grid electric power generation. My original goal in watching your videos was just to get a good rocket stove reference that didn't require welding. Instead, I've been binge watching for two days and then I subscribed. Your ideas are brilliant. If and when I complete my animation project I'll have to post a link to your videos.

Intreaguing, I really hope I can build something like this one day. Thanks.

so the water makes the cycle itself? i assume because hot water wants to raise up, it automatically goes into the bucket itself? replacing itself with new cold water from below? i keep seeing this type of water heating from a stove but in none of the videos it explains how it works,

*@GreenShortz DIY* 1: You need a 1-way valve on the hose, to make the water circulate, without it the water will expand in both directions & you get hammering that can damage the system. 2: You should have some clay on the inside of the copper tube, to protect it from the intense heat and corrosion from the fire. *Watch this:* ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BREQY1TL7JA.html

That was cool. Always super satisfying managing to build one of those devices that heat water with only super durable stuff. Now what I want to know is how this model compares in core temperature, gas emissions, and volume of BTUs transferred to water, to a model made with the same cob and the same heating chamber core surface area, but which has the coil in the place where you would put the barrel on this rocket stove : on the way out of the hot fumes, but not in the heat riser itself. Because in the rocket stoves DVD they say that the second is better. Hey I'm building one right now!! Maybe out of stainless steel if the shop say they can weld it for me at a reasonable price. It's just to hold the ceramic boards in place, it's not the actual rocket stove.

TY! Been wondering. Why is the riser section necessary? Why can't you go straight from the burn chamber into the Mass/water material then out the flue?

Check out making AIRCRETE Then make a Rocket stove from AIRCRETE material!

This is brilliant. There has to be Irish 🇮🇪in here somewhere 🤣

i wonder how well one of these water heaters would work if you had a much larger metal tank, like say 6 ft tall and 24 diameter and had a small pump pushing the water thru much quicker. just the mass of that steel tank full of hot water could keep a greenhouse above zero over night when its freezing out.

You could have wrapped the tubing around the pipe. And saved yourself some exertion. When I go that route oh, that's how I'm going to do it.

Incredible.....just want to be off grid so bad when I watch stuff like this. Thanks so much for informing us all how easy it can be with DIY projects my friend. I love the color of the red clay can a person buy it if they don't have access to this type of clay?

"Stoked"...no pun intended I am sure😎 Nicely done...I am interested in your follow up video. Thanks

Instead of plumbing coil look at the AC copper coils. I was told they're easier to bend.

Great stuff as always. TY Is cob better for water heater ? Or is you's pear lit, sand, concrete mix better ? Heating water wies.

Put removeable, press-on "Sharkbite" cap on one end of copper, a press-on valve and fill copper with tap water COMPLETELY getting out ALL OF THE AIR. Shut the valve. Bend around form. Water will not compress, tube will not kink. Then take off cap and valve

When you say you put the hose up the coil on the inside, what is keeping the hose from melting inside? Please help me to understand that particular step of the process please. I'm a first timer. Thanks Enjoyed the video!!!

why don't you turn this into a back yard cooking/heat/cold+hot water sink project using a countertop sink?

It's a RU-vid video I was watching called "No Electircity Needed Heater" she says using crisco makes the candles more efficient more effective.If that's possible you can save money.I will use bigger candles for that experiment and bigger flower pots.And put a metal tea pot filled with water on top with a vent over it with a fan to blow the steam.And carry some extra tea bags and some sugar and try using a metal pot that don't rust.You can Google pots that don't rust and it will give you the names of the pots that don't rust.

Making 1-2inch gap between copper coil and sand will allows more flame to hit the coil.

Pretty good idea. Not sure how you would mix tgr water- I guess run this into your hot water plumbing and run the cold water direct and attatch them to the shower plumbing ? W

Did you have problems with soot building on the copper tubing? thus reducing the efficiency of the heat transfer to the tube

Awesome demonstration! The next part should answer so many questions i have. Thank you, much appreciated!

Good attempt, although you should have the top coil from the stove going in to the bottom of the bucket, that way you heat all the water in your bucket. Remember heat rises!!!!

How long did it take to heat the water to touch hot? You're losing heat out the top of the chimney. Could put a kettle on there😊 or make the coil go up farther.

All wrong. Chimney too short. Copper line way too close to burn box. You're not forcing the air down again and through anything. You want the area near the burn box to be the hottest, to reach full combustion of material, which means no cooling it down with water. You want the coil toward the end of the chimney, ideally after forcing the air back down and horizontally through something else - ideally this is where the copper tubing or radiator would be located. Where it is now, the water is interfering with reaching full combustion of material. It's almost a wood burning stove in this configuration.

Just an idle thought, if you want more perilite, couldn't you sandwich some between the mix & the cobb? Make a slab of the three & wrap it around the coil.

If you can do anything with fired clay (not sure if you've got a kiln anywhere your setup), it might be neat to try making interlocking sleeved cylinders. Shouldn't be too different than making pottery around some forms. Then after firing those, you could stack those sleeves to be used as a chimney liner for something like this. Perhaps adding one or two feet to the height, since those would help support the surrounding clay/cob from deforming too much.

Thank you

Would it be more efficient, and safer if a damper was designed near the top of the chimney? That way the flames would be contained and the heat more concentrated around the tubing?

Thanks 4 the vids - about to make one myself. What about making the j tube firebox since u r 1\2 way there anyway? May get a hotter burn.

Sounds like you live next to an Airport/Garbage Truck Facility that is currently under reconstruction... but is still fully operational...lol!

good video again. i still am wondering if you are putting the coil in the hottest point of the fire being in the chimney. I think this could should really be put into a rocket stove mass heater from the top of can lid down the can. even using some form of gas this principle would capture much of the heat before it goes to a bench and could heat the whole floor of the house ? where are all the fire bugs developing home heating systems that burn junk mail? any time you want to be the show guy behind the ideas, let me know. lol. only kidding

could have wrapped the coil in carboard and then cob over the top, the carboard would hopefully burn off leaving a larger surface area of copper and hpoefullt yhe chimney dosent collaps when carboard burns away

Copper/Melting point 1,984°F , I have been looking for a cheap way to melt copper .

Would've it been better to have the hot water enter at the bottom of the bucket? Heated water should enter at bottom while the cold water is at top. It's called stratification. Hopefully that'll help.

Why would you need to heat hot water? It’s just called a water heater. Not a HOT water heater. Why would you heat hot water?

Videos are starting to get unbearable to watch now on RU-vid with the amount of advertising breaks..

Now you can cook while taking a Hot Shower,

la bestia

Just curious as to how many gallons of water you could have heated to a boil by just placing a pot with water in it on the top of the chimney in the same amount of time. Nice project though.

Will be more efficient If those flying flame was used to heat anything else.

If you had a hose coming in from a tap and the other end - hot water coming out - run a bath with it - we had them as a kid in Aust - Chip heaters - having a bath or shower with all the hot water you need from just kindling

All of this is nice , but Im wandering how long will copper pipe hold on this kind of temperatures?

Next time or to whom try this . Wrap the copper pipe around the 4inc pvc. Plum this setup to a hot tub . Or make a hot tub from a old house tub and enjoy . Water in from the tub and back in

Why not use gravity and have water run throu it. Im sûre it Will ne boilling from the simple passage they the coil

Metal bucket on the chimney = 5 times faster = 5 times less firewood = less pollution

I’m sure they wouldn’t be saying that if they had a father or mother there one of those nursing homes and they didn’t have any money and they weren’t famous

Muito bom parabéns

Looks like to me that it'll be making steam instead of hot water. You had some fun anyway.

Really neat design! This could be incorporated with a shower house, a hot tub, an outdoor cookstove, or add to a spa-like environment Once this is finalized, I’d use copper pipes or pecs designed for heat for the hose. Also, wouldn’t it be better for the heated water to got the bottom of the bucket (instead to the top) and the cold water to come from the top? As hot water enters the bottom of the bucket, the heat would rise, causing a convection current so the entire water mass increased gently, instead of downward in layers. The cold water, being heavier, would lend to cycling faster from the top, as well. Once the cob dries and bakes, this will become much tighter and more efficient The way you have it now lends to maintaining temperature layering and would be harder to draw from with a spigot, as the first water you draw will be the coldest. Nice prototype experiment! Excellent explanation I like your long-fiber use of cob!

Why use plastic pvc? Won't that melt? Why not use a regalure still cheamily pipe?

You can take a paint brush and dip in water to smooth out the cob

thanks for the nice video but the sand clay mix does not crack when it dries? thanks

Love this build! would be interesting to see the difference between having a coil or just heating a boiler over the flame and letting that thermo-siphon into another container instead.

Part 2 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-afWJ6P_yCRg.html

Step one make pot from concrete. Step 2. Put pot with water on fire. Much simple

Conical shape of open coils in the chimney would pick up more heat perhaps.

When you bend the coil you could possibly have used an appropriate sided pipe to wrap it around for stability as you shaped it .

had to laugh with the siren, nothing to see here, move along. lol. i enjoyed the video, thank you

Use a pond pump to recirculate the water... Works wonders...

Паро водяное отопление без электронасоса ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JpolO6tInmg.html

It's not free if it relies on fuel in the form of wood or pellets. Wood collected isn't free, it requires labour, labour is a cost, especially if it's your own.

Que pasada de trabajo harías funcionar la calefacción de una casa con esta estufa?

Once the cobb is "cooked", can you put a pot to cook on the chimney? It seems like a "waste" of good heat up there (and as others mentioned, definitively a much taller chimney and more copper pipe would make it much more efficient... but I want more!!)

Good day my friend nice vedio god bless i hope stay connected

One can heat water by putting the metal based water pot over the flame

I appreciate your ability to work with out paralysis by analysis. I love to work, however I have often been my own worst enemy by over thinking or too much *attention to detail. (* I am often hired for this quality, gift/curse) I have a dear friend on the East Coast, Frankie. He would make a decision to do something, and do it. Where I have spent more time thinking than doing. Thanks so much, greetings from Colorado Springs Colorado, Christopher.

I think it would be important that there is always water in the copper tube because it would probably be approaching the melting point of copper in there. Great idea, though. You could also use it as a floor heating system if there were piping in a cement floor. Be good for a green house or even a small house. No chance of fire indoors that way. I guess the question is how long would it last. That's quite a bit of heat on the copper. It might structurally fail after some time. I could do something like this on my stove pipe, but I hardly use hot water anymore for bathing. I wash with a pitcher of water and a wash cloth. Everything else seems so wasteful.

Great idea. I bet people in California are wishing they heard about this before their power was turned off

just one question... haw long takes you to heat up water to the decent tem, let say 60degC? Idea is amazing... i'll will use it in the woods anyway :)

Pot stand at the top of the chimney for a cook-stove & water heater combo?

The Hopi Indians in the SW USA built adobe dome dwellings called “hogan” that kinda remind me of your mud rocket stove. Doorways and Windows about the base with a central chimney. Fun project! Thx!

СИРЕНА ЗАВЬІЛА ,Я ПОДУМАЛ ЧТО ЗАТОБОЙ КОПЬІ ПРИЕХАЛИ.