Matthias Hacker

Maybe of interest for those who want to build something similar, this is my small rmh wich i build last winter.

The core is a DSR3, it has in internal flue gas channel from where the pipe exit is visible down to the bottom, with a flap on top of the channel as as a bypass.

These barrels are made for shipping foods like peanut butter. I welded one lid to the bottom of the upper barrel, and later cut a large opening into as well the lid and the bottom of the upper barrel. That makes a perfect tight fit for stacking one barrel onto the other.

Now I’d like to build something similar, but with a shorty core and a t-style bypass on the outside, similar to Peters heater. And an easier way of dry stacking bricks inside came to my mind. My goal is to be able to build a transportable heater within a few days at low costs.

Another question came up, I’m still thinking about numbers and size…

Is it possible to build a shorty core a bit shorter (in length/depth) than specs? I am now leaning towards a 140mm (5.5 inch) core size, wich is my chimney diameter, but there is a restriction in total depth of the core, at least in the way I want to build the bell. Base number would be around 100mm,  so 4xB for the depth of the burn chamber would be 40cm, but I don’t need it to be deeper than 33cm.

Thank you guys!

Thank you Benjamin,

so I will look for a flue pipe that has at least system size. Not that easy to find here where I am, but will be possible.

Sorry stove is not the right term, I mean heater.

Liebe Grüße aus Serbien!

Hello to all of you

I’m thinking about building another small batch box rocket stove. Last year I finished a DSR3 and am really happy with it, but the idea of building another one with a shorty core keeps spinning in my head…

So a questions came to my mind
can I make the connection of a 130mm (5,1 inch) shorty core to the chimney with a 120mm (4,7 inch) flue pipe? The total length of the flue pipe might be around one meter, with three 90 degree pieces in it.

I guess this is not a good idea, but I like to know about your opinions first.

Matthias Hacker wrote:

After the heating season I will take everything a part and see what the stripes look like. I don‘t expect them to dissolve by the time, they are not directly exposed to heat and oxygen. If they are getting softer during the hottest burn, that wouldn’t be in issue, because they are  not structurally stressed.

I promised to make pictures of my stripes of stainless steel, so here they are. What do you think about it? I am not concerned. I could take my core apart and put it back together like a puzzle without any problems.

Nancy Reading wrote:Do you find the knob is getting hot? I Think that the wooden knob (although it looks nice) might not be durable.

Hello Nancy,
I‘m happy you like it!
the wooden knob is a getting a bit warm, but far away from getting hot.

Regarding the Shorty upscaled, yes it has been done with success, you might want to take a look at this thread on donkeys, all dimensions have been discussed with Peter, as well as a Sidewinder construction. All the dimensions for scaling are there, you only need to convert from mm to inch.
https://donkey32.proboards.com/thread/4091/shorty-batch-160mm-system-brick

Hello everybody,

I found a nice & easy way to make a door lock, that might be worth sharing. I did see something similar somewhere before, but I cannot find it anymore. However, take a look at the pictures.

The metal rod is 6mm / 0,236 inches in diameter, and it has quite some flexibility before deforming/bending. At first I had that rod straight, which worked as well, but much better with the 180 degree bending, this gives the rod more length and thus more flexibility. Like this the door lock doesn’t need any movable parts.

Note that the hook is only welded to the doorframe on it‘s lower part, while the upper part has a tiny bit of air in between the rod and the door to move freely.

Mounting the nuts inside the doorframe is rather easy for Shorty and DSR3 doorframes, because they have an opening at the right spot. When using a stick weld it’s possible to weld through this opening.

Note that the nuts are not welded directly onto the doorframe, but on a stripe of metal, wich is tagged to the doorframe. One might come away with simple sheet metal screws, but I don‘t trust them that much.

The holes for the screws in the lock are wider than the screws, so the lock is adjustable.

If a rocket stove should burn clean, so clean that you might be able to have food in contact to flue gases, then it will be hot, very hot. If you want to have it like this, go ahead. Or you construct a kind of heat exchanger, that will cool down the flue gas before it comes in contact with your food.

I much prefer to grill on medium to low temperatures, which is only possible with coals. I made myself a grill with refractory slabs and it works really fine.

Do you want to grill directly on coals or with a kind of pan in between the fire and whatever you want to grill?