Matthias Hacker

Hello,

maybe of interest for those who want to add mass to a barrel. I recently made my own clay bricks with success. Working with clay is a nice thing in general. It´s an excellent heat storage!

I did use pure clay, I only added some dry sand in case my clay had too much water. The clay should be stiff, so that it remains it´s shape. I applied some oil to the template like you would do with a cake pan.

Best, Matthias

Hello everbody,

some questions came to my mind while making plans for my upcoming Shorty build. I hope it´s fine to ask them here. I searched the forum but didn´t find these questions asked.

- The V-shaped floor, is it essential? Coaling down is faster with the V-shaped floor, as I understood, right? Since I am planning to build a small core due to size restrictions, this floor design would make the burn chamber even smaller. And I don´t like to cut refractory too much...

- How do you guys take out the ash out without pushing it into the port of the burn chamber?

- Is the Shorty core prone to smoking back into the living room? If so, might a bypass higher in the bell (above the endport) help?


I have refractory slabs available of 250x120mm and 300x150mm and I found out, that a small 131mm system size core can be build with very few cuttings using this dimensions. Looking forward to start my build soon.

Thanks, Mat

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.