Rocket Stove as Heater

[Tim McCoy]

I know that winter may soon be over for some of us, but was wondering if anyone has experience using a rocket stove to heat their shop/work area? Below's a link to a UK blacksmith that offers rocket stoves. Seems like they could be an efficient and cheap way to get heat where there is no other way without having to rely entirely on your forge. Especially if your spending time doing cold work. Just wanted to hear from some of you before gathering the stuff to put one together. All comments appreciated!


http://www.rocketstoves.co.uk/

[John B]

The guy who makes and markets those is a member on here, he may step in with a few words of advice for you.

[Dean Aggett]

Thank you for the link to my DK Rocket Stoves web site, The stoves are all jig built to maintain the high efficiency and smoke free running, as you can imagine a stove this small burning so well so as not to produce smoke and stay lit is a tricky thing it took nine months of R and D to get right.the fire in these burns at a very high temperature due to the balance of primary and a pre heated secondary air system flowing at the right rate to consume the wood fuel almost completely, its like magic to watch http://www.youtube.com/watch?v=WEzGFegRTwU. hope you enjoy.

[Greenbeast]

what do you think they will be like for keeping a 'shop warm? as opposed to cooking on?

and does the fire require a lot of upkeep (not convenient when busy working)?

[eric sprado]

Aprovecho,a non profit organization in Cottage Grove Oregon,developed what they called a rocket stove years ago that was made from tin cans with a pair of tin snips. Not as nice as Dean's stove for sure but I do have the plans if anybody wants to make a neat LITTLE camp stove. If you visit Aprovecho's web site they also have a larger stove in production for Third World countries to use that don't have much fuel.
These may not be in the same class as the DK stoves but they are probably worth a look for folks who live near Oregon..

[WayneCoeArtistBlacksmith]

I'd be concerned about carbon monoxide if using in doors.

[Pat Roy]

I can't believe anyone would consider trying to use this as a heat source for a building. It's a cooking stove as the advertisement says. Unless you put a hood over it with a smoke pipe, you will kill yourself with CO.

[arcc]

Aprovecho,a non profit organization in Cottage Grove Oregon,developed what they called a rocket stove years ago that was made from tin cans with a pair of tin snips. Not as nice as Dean's stove for sure but I do have the plans if anybody wants to make a neat LITTLE camp stove. If you visit Aprovecho's web site they also have a larger stove in production for Third World countries to use that don't have much fuel.
These may not be in the same class as the DK stoves but they are probably worth a look for folks who live near Oregon..

I worked with Dr. Larry Winiarski(Who invented them) when he come to Sifat for years building Rocket Stoves. They are extremely easy to build, however I don't think they would work good as a heater if made for cooking. The better insulated they are the better they work. One thing they can be used is what we called a saw dust heater. Using the rocket stove principle and some old coffee cans, you can set a heater that burns only sawdust and stays hot for hours. I still wouldn't quite use it indoors though.

[Greenbeast]

I'd be concerned about carbon monoxide if using in doors.

I can't believe anyone would consider trying to use this as a heat source for a building. It's a cooking stove as the advertisement says. Unless you put a hood over it with a smoke pipe, you will kill yourself with CO.

well obviously!

but does the functioning of it preclude the use of a flue?

[Drewed]

Not possible. It may not produce visible smoke, but burning wood produces CO.

[Greenbeast]

i don't understand, humans have been burning wood for heat for thousands of years, in fact in open fires indoors for hundreds of years.

shall we go back and tell them it's not a good idea?

[ThomasPowers]

Greenbeast; how much air flow were in those "houses" back when there were open fires? Modern houses tend to be quite different so using an example from centuries earlier is not a good analogy.

[Greenbeast]

not a good comparison with modern houses but the original question (and my follow up) was for workshop heat

[Greenbeast]

It could be that they don't take to a flue very well, or that they require more fire maintenance than a closed woodburning stove using large logs, in which case this'll all be moot!

[John B]

Pot belly wood stoves or Chimeneres(?) radiate heat, the rocket stoves cook on top of the flue so extending it would not be as useful for surface area to radiate heat,

Right tool for the job seems to spring to mind here.

[Greenbeast]

Pot belly wood stoves or Chimeneres(?) radiate heat, the rocket stoves cook on top of the flue so extending it would not be as useful for surface area to radiate heat,

Right tool for the job seems to spring to mind here.

fair enough!

i will track down a used wood stove for next winter

[ThomasPowers]

In the states you can buy kits to modify a 55 gallon Drum ("oil drum", "oil barrel"), into a wood stove. Adding a second one above it with the flues offset from end to end can help the heating capacity a lot as well. They don't have great longevity, usually a couple of years; but the kit pieces can be then transferred to a new one.

I know several folks that use them in their shop and then unhook them and move them to storage during the summer.

[John B]

fair enough! i will track down a used wood stove for next winter

Simple enough to make one from a gas cylinder just take care when cutting through, make sure gas is gone

Plenty of info on You tube, some of it good.

[Glenn]

I have been studying this and other burners for a while now. The rocket stove is (as I understand it) designed to be used as a cooking fire, burn small amounts of wood, in a small fire, at a very high temperature therefore very little or no smoke. This is vastly more efficient than an open camp fire. They are made even more efficient by surrounding the cooking pot with a heat shield and keeping the heat in contact with not only the bottom but also the sides of the container. These work well outside or in extremely open mud huts in 3rd world countries, and other areas where the buildings are not "tight" and leak vast amounts of outside air.

The next refinement is a rocket stove mass heater where the rocket stove is used to burn the wood in small fires at a very high temperature and the exhaust gasses are then directed through a long pipe system (many times horz) to heat up a mass structure and finally exit the building through a chimney. I can not see where this would create enough draft to work, or any way to clean out the long pipe system of ash etc. But they are being used and seem to work.

A similar system is used with a multi-path chimney mass where the chimney gasses are run through a system of openings to heat a mass of brick and mortar. The idea on both is to extract as much heat from the exhaust as possible and store it in the earth, mortar and brick or other mass.

The drum stove has been around quite a while, from WW2 at least. Remember the 55 gallon drum heater in the series M*A*S*H from the Korean War era. These were single drums in a upright configuration.

The single drum wood stove horz (on its side not standing up)is a better arrangement as it burns the wood in the front and pre-heats the remainder of the log. It holds the heat into the stove longer and allows more heat to radiate from the drum. The second drum holds the heat into the stove even longer and allows more heat to how radiate from both drums. The second drum almost doubles the heat output of the stove.

Once up to operating temperature the double drum stove (my stove, my location, my wood source), there is very little or no smoke from the chimney. I have used a double barrel stove for over 20 years and am on the second set of drums. Like all fires, it is alive and must have constant attention in order to be safe.

[Tim McCoy]

Thanks so much for all the input - the comments about concerns for CO2 are well taken, especially for non-vented areas or workshops that are airtight. Glenns comment about the mass heaters is also spot on ... all that would have to be done for Dean A's rocket stove to be a heater is to place a large firebrick on top ... the escaping heated air would heat the brick which would radiate heat during and after the fire (thanks for the link Dean).

I saw a You Tube entry that had a rocket stove created out of just firebrick. Seems that the rocket stove ("invented" around '80-82) can be as sophisticated or simple as needed.

Cost containment forces me to work in a more primitive setting. I have a micro shop, interior is 7x7', dutch style door and the distance between the top of the walls and the area where the eaves stick out past the exterior of the walls is about 12" so there is lotsa draft. It is constructed so that most wind is kept at bay, but there is always plenty fresh air. I'll add some photos this week-end. There is no power to the little building and no plans to add any, hence a need to have a secondary heat source (fired by wood/coal/corn/charcoal/what ever) when the forge is not burning something. For those of you that have to work with little space you will understand that except for large sized work, much can be done in this small area. Forge, some kinda striking surface, slack tub, vice and oil pot setting around the walls allow the smith to still work while his hand tools hang from the walls - everything else goes outside.

Seems that in a work space that is vented by virtue of being built on the cheap with scrounged material, a small heat source that can be built from more scrounged material that provides almost complete fuel consumption could be the answer even with the drafts. When I first saw the rocket stove I was intrigued by it's simplicity - it's an "L" shaped tube that burns consumables like its name implies - and almost anyone can build it. I think I'll give it a try.

I'll let you know how it works!

[Greenbeast]

Simple enough to make one from a gas cylinder just take care when cutting through, make sure gas is gone Plenty of info on You tube, some of it good.

Yeah i might do one of these, my first forge (that's just been superceded) was built from a 15kg butane cyl, was definitely over-cautious when prepping the cylinder.

[JimsShip]

As a parent of a small child, my first thought after seeing the video was how unsafe that pot of boiling water looked on top of that thing!

[Francis Trez Cole]

looks like a great camping tool

[Glenn]

The Dakota fire pit is about as simple and basic as you can get.

Dean
I think Dean Aggett's design solves several of the problems with the rocket stoves. First off it is heavy enough to withstand several fires. Second it can be adjusted for heat output (great idea Dean).

Tim
Do not think that because you have a building with an open door that the building is ventilated. The gasses can travel to the inside and collect inside the building even with the doors open. I have seen it happen.

To solve this problem
Why not build Dean's design and place it OUTSIDE the building. Next connect the top of Dean's stove to a say 4 inch sch 40 pipe and run the 20 feet of pipe horz through the shop building, out the far wall and into a chimney extending above the building roof. The exhaust would flow through the pipe, heating the pipe and then the room with no internal fire, fumes, etc. I can imagine that the pipe would get rather warm (hot) and precautions would need to be taken to protect the interior walls, and other stuff, from the radiant heat. I would put a couple of clean outs in the system just in case there might be an accumulation of ash or other material. You see the same set up overhead above the buggy storage in Walmart and in warehouses over the bay doors. They are gas fired and give off a good deal of heat.

I suppose you could use lighter gauge pipe but being a blacksmith we think heavy and build heavy once (grin). The possibility of something falling and separating a single piece of sch 40 pipe is remote, but I can see it happening with other systems. The good thing about Dean's design is the fire can be easily put out when your finished. This is a very important safety factor to the system. And as Jim suggests, there should be some type guard to keep small children, animals, etc away from a warm (hot) pipe and the stove outside.

Personal safety is just that, you taking personal responsibility for your own personal safety and the safety of others. These are only suggestions, concepts, and ideas that have not even made it to paper napkins yet. Use good judgment and common sense in everything you do. If you build one, and it works, let us know.

[Tom Allyn]

I built a rocket stove and use it from time to time. It's a cook stove. I wouldn't want to use it as a heater because it requires frequent tending, advancing the fuel into the fire chamber.

Mine is made out of a propane tank and some 3-1/2" electrical conduit.
CAUTION - electrical conduit is galvinized and the galvinizing MUST BE removed before using it in a stove.
The stove body is insulated with wood ash. I've also built a shroud to focus the heat energy around the pot. The shroud attaches with magnets.

The fuel is fed into the stove on top of the flat shelf in the intake. Combustion air flows up through the lower half of the intake. I generally use handfuls of twigs as fuel.

This stove will heat one cup of 50° F water to boiling in 2 minutes.