The rocket stove

[Spindrift]

@richhodg66
All components are made from 4 1/2- inch stainless steel pipes, because that was what my friend had at hand (scrounged them many years ago). This is the first stove he has made, kind of a «prototype». There are many instructional videos on youtube, some of them are actually quite good (search for «rocket stove»).

The «feet» are just rings from the pipe, welded together. It is actually quite stable, but more rings could be added easily. I’ll consider this as I get to test it more. A wider «crown» at the top might also be a good idea.

One design feature I’d like to recommend, is having a functional lid at the oblique pipe, where you put the firewood. Not all designs incorporate this. It seems to make a huge difference in air-flow, and effect.

 

[Tomme boy]

@Snakeoil this guys version was what I used as a base to make mine. The burn basket is very critical to make this work.

 

[richhodg66]

So it would appear that the vertical upright pipe is about two feet long or so, correct?

Good advice about the lid, I would not have thought of that. I may see if my son can put one of these together for me in the near future. I render scrap lead down using a wood fire, but I've justbeen suspending the pot over a camp fire, works, but not real efficient.

 

[Bret4207]

A few years ago, I believe it was Ian(?) who posted a pic of a little kid with a welding helmet and a stick welder, with the caption that went something like "my dad says if you have to grind your welds, you're a grinder, not a welder." If it wasn't Ian, it made me think of him anyway.

I can't fault your friend's boy's work. I'm a "grinder." I weld for five minutes and grind for twenty, which makes the low duty cycle of my little HF portable wire welder perfectly appropriate for my skill-level. Five minutes of welding, twenty minutes of cool-down, this thing will be in my estate sale, because I'll never ruin it welding too long with it.

The boy did better than I would have.

"A grinder and paint make me the welder I ain't!"

 

[Spindrift]

@richhodg66
Yes, the vertical pipe is about two feet.

 

[richhodg66]

I don't weld, but my oldest boy, who did five years in the Marine Corps, got tired of being an infantryman, got out and joined the National Guard as an "Allied Trade Specialist" I forget the MOS number, but basically supposed to be a welder and machinist, occasionally gets to do stuff on his own at drill now that he's assigned to a real maintenance unit.

Gonna try to get by the scrap yard and get some stuff for him to try this, I have quite afew buckets of jacketed pistol scrap this would be very helpful to getting that stuff rendered down into a useable form.

 

[Bret4207]

FWIW, we found that thermal mass makes a huge difference on any stove, Tommes rocket stove should apply. Over the years we found any flat or not too steeply curved/slanted top surface where the heat gathers is a good place to add mass. The easiest thing we found (Dad and me) was to use tire chains, something that used to be laying around all over the place in the day. We'd just heap them on top of the stove and there ya go! They were mild steel and didn't get all that hot so they could be used if needed, but most were pretty worn out. Worked in the chainsaw shop too. Anything like that will help transfer/gain more heat out of the system. It's sort of like the old cast iron steam/hot water radiators that provided a much more even heat than the modern fin types.

 

[JonB]

So it would appear that the vertical upright pipe is about two feet long or so, correct?

Good advice about the lid, I would not have thought of that. I may see if my son can put one of these together for me in the near future. I render scrap lead down using a wood fire, but I've justbeen suspending the pot over a camp fire, works, but not real efficient.

I have always thought, if I were to melt some scrap Lead (not raw wheel weights), I'd consider the simple cinder block rocket stove.

 

[JonB]

OR,
I'd make one with a larger firebox with smaller bricks...a design like in this video, but again, larger firebox.

 

[RicinYakima]

I have always thought, if I were to melt some scrap Lead (not raw wheel weights), I'd consider the simple cinder block rocket stove.

Be careful with the concrete blocks idea. Unless you live in the desert, they hold a lot of water and when heated it turns to steam and cracks, sometimes violently. Plus they hold very little weight when hot without rebar.

 

[Snakeoil]

i forget where i got it from, i've been using it for several years.

It's a classic. Funny and sad at the same time. Sent to a couple of guys I shoot with. Told them I put a scope on my Ruger.

 

[Snakeoil]

Be careful with the concrete blocks idea. Unless you live in the desert, they hold a lot of water and when heated it turns to steam and cracks, sometimes violently. Plus they hold very little weight when hot without rebar.

The guy that made that video (should have been about 3 minutes long) is in India or Pakistan. Doubt there is a Home Depot where he can get fire brick. Based upon what I read last night, the stove got its name from the roar that is created in the 2nd burning chamber where the gasses produced in the primary combustion are created. This guys stove did not seem to have that roar. The concept is the same, but my guess is his dimensions might not be right.

A late friend of mine built a new log cabin up in the Helderbergs above me. His heat was provided by a wood burning furnace that I now believe is based upon this same principle. When I was researching the rocket stove, I found an article where you put one under an inverted 55 gal drum and similar to Jon's compressor tank the drum becomes a radiant heater. His was fully enclosed in an enclosure that was filled with sand so no radiant heat. Instead, it had a hot water heating coil in it. Plus that huge mass of sand (about 4' x 6' x 6') was a heat mass that would stay hot and provide consistent heat. My cousin (his neighbor) tried to explain it to me and now I understand what he was talking about. He said the wood did not burn, but rather produced gas that was burned in the chamber above. But I think he simply did not have a good mental picture of how it was built. He did say that a chunk of wood would last all day. And I remember when I saw it, it had an upper chamber that looked like a 55 gal drum, size-wise, but was made from heavy rolled steel plate. He built that house at least 20 or more years ago.

 

[RicinYakima]

Those designs were very popular in Mother Earth News during the 1970's. The one I saw was expensive to build and hard to get started, as it took four hours to get it up and running. However the "Coker" chamber did an excellent job of driving off the water and letting the combustible gases up into the living area burner. But it was cheap! I was burning two cords of wood a winter for my 1000 SF house and he was burning half a cord for about 1400 SF.

 

[richhodg66]

I have always thought, if I were to melt some scrap Lead (not raw wheel weights), I'd consider the simple cinder block rocket stove.

I tried that cinder block one, couldn't get it hot enough to render down range scrap.