Benjamin Brondbjerg

he airframe construction for Shorty requires welding and cutting and must be built exactly to specifications.
The door for Shorty is easy and can have a large window.

Is the airframe essential to the build? In the original post by Peter he just stated that the door would need at smaller CSA? Maybe i'm missing something here.

Your bell needs a bypass, and almost all should have one.
With a 3' horizontal to your outside chimney, you want a steady stream of hot air to get the system moving up and out of your house.
Build your outdoor chimney with a cleanout door you may need to put burning paper in it to start the draft on a cold chimney.
Believe me when I tell you there is nothing worse than a stalled rocket stove venting indoors!

the chimney i'm looking at is 3.75 meters tall ø200mm very well insulated chimney . Schiedel is the company name. I'm looking to by this kit used for 400 bucks. What a bargain:
https://www.dba.dk/skorstensroer-helt-nye-skor/id-1113428668/
It's a diy lego like kit, so i can always adjust / make higher if i need more draft.  But because of local regulation i will have to move a window in my roof if i make it 3.76m tall....i know right? So would like to avoid that

As far as the P-channel, nobody builds with them anymore.
The floor channel has replaced it.
My quick-change secondary design is easy to make, the 6" riser stub can be plain carbon steel or the RA extreme heat material and swapped out in moments.

nice! I wasn't aware that this was the case.

Now my two cents worth.
As a first-time builder, a traditional Batchbox is easier to build than a Shorty core, but I just built a Shorty and so can you!
You can study my threads on Shorty construction and airframe construction and build what you feel comfortable building.

I've read the threads. Good read! again: is a steel frame around the whole core essential? I don't understand the purpose of the airframe still.  I would like to make the door Matt walker style (with a fire proof glass off course) without welding because i don't have that skill available in my social circles.. yet!  For support i'm thing to insulate the core (superwool) and add bricks for support in critical areas.

I've added a rough sketch of the room. I'm thinking to make a small height difference in the cooking/ baking area and just leave the bench exposed to the rest of the build with an apropiate CSA. (following the stratification reverse water line of thought). But i would love to be corrected. My reasons for liking shorty is:
refueling posible
low bell makes for higher position of stove - wife aproved and more apropiate for what i want to do with the core. (We're both 1.9m)
batch box advantages

thomas rubino wrote:That is a refractory tile. apx.  21 x19 x 3 thick
It does not say how high it is rated but probably 2500F +
It would make a fine batchbox roof.

Would it be possible to build almost the entire core (except the half brick lifters in the burn tunnel) with the slap?. There's a sale on the slabs now for 40 bucks a piece. :)  I'm thinking of building a 200mm shorty core with a bell and glass top cooker using a scheidel chimney. I alwyays found the whole p-channel apaling anyways.  If the bell is maximum CSA, will it affect draft? I want to build the chimney 1 meter apart from the building because of crazy chimney building regulations. i plan to connect the bell and chimney using ca. 1.5 meter insulated stove pipe with at slight slope. Do i need a bypass for this?
Plans for shorty:
https://donkey32.proboards.com/search/results?captcha_id=captcha_search&what_at_least_one=chimney&who_only_made_by=0&display_as=0&search=Search

https://physicsworld.com/a/thermophotovoltaic-cells-top-40-percent-efficiency/

The first thermophotovoltaic cells with an efficiency of more than 40% – higher than any existing solid-state heat engine, and exceeding even the average efficiency of turbine-based power generation – have been fabricated by researchers at the Massachusetts Institute of Technology (MIT)  

Well. Isn't that exciting? imagine sticking solar panels that could handle 1200 deg C in a 10 inch batch box  but as with all new things:

More funding required

even though:

“Usually, TPV targets bandgaps of around 0.7 eV with source temperatures lower than 1300 °C,” LaPontin continues. “Since there is an almost constant ‘penalty’ you pay on the voltage produced, moving to higher bandgaps (of 1.0 to 1.4 eV) confers an advantage. Indeed, as you move to higher bandgaps, you get higher voltage and the penalty becomes a smaller fraction of the total voltage, thereby leading to a higher overall efficiency.”

i had an evening off in the shop and decided to retrofit a L-style rocket of the pieces i had laying around. an old stove, 50 cm of stove pipe, 5 refractory bricks and 50 cm of flexible piping.  I heated the entire shop with this thing by using 30*30cm of 1 inch plywood and heard the rocket and saw the "smokeless" fire. What a night!  I'm hooked for the investment now building something more proper.  

question: does anyone have a clue what this is? insulated brick or just refractory
https://partisalg.dk/produkt/ildfaste-sten-542x492x8cm-pris-kr-200-stk/

Wow! what an overwhelming response! Thank you for all the lovely answers.

I don't know how to use the forum yet, so I'm trying:

There is no good substitute for using heavy full-size firebricks to create your rocket core.
Beyond the core, your choices go up.  
Solid clay brick is very common.
Concrete blocks can be used in certain spots.
55-gallon barrels can be cut length-wise to create a half-barrel bench with no piping.
Stratification chambers (bell) can be built to fit in any location.
Tell us what you have in mind.  

I think Matt Walker disagrees. His designs got me thinking about using these boards. Even though i know it's not CF board.
I think i might want to build em all eventually. I've build several dry stacked J-tubes for now and i think i found a new hobby My heating needs probably suits a 6 inch batch box build from what i've understood. Just so many builds to choose from and so many materials. I like the simplicity of J-tube designs, the complecity of a clean Batch Box build and the ease of mind of just buying a plan. But economy and building time is tight.
Honored to have you answer. I've seen all of your material on stoves

Cristobal Cristo
Post Today 22.33.07     Subject: Calcium silicate board with clay and sand mortal
Regular clay/sand mix will quickly crack and will probably fall off due to shrinkage and different expansion ratios.
Using zirconium coating could help a little against flame erosion, but the boards are so soft (I have some) that they will be quickly destroyed by loading and cleaning.

That's a pity... I've never actually touched the boards. It is my understanding that the same is said about CF board builds. How does the softness compare?

Fox James
Post Today 22.17.59     Subject: Calcium silicate board with clay and sand mortal
You could try painting it with Zircon.

thank you for your response! I'm a YT subscriber of yours You made me fall in love with the idea of J-tubes again again..  not making it easy on me  here

Hello Permies

I wish to begin expirementing with Rocket science. I've been on a scavenger hunt for materials and have come by multiple used Calcium silicate boards from the company Skamowall. I've read the data sheet and it says the product has a melting point of 1345 deg C. (2453 ). But i've read comments here saying that the flame path will somehow destroy theese boards anyways. So i was wondering if it would be possible to use theese boards as a casting box for a core and heat riser ( 8 minute riser technique) with maybe 1 inch of clay and sand mortar in the flame path inside a box of calcium silicate board. This technique would make the entire build 5x cheaper in my case. I plan to mark the correct dimension on the board and then basically "fill to here" Is the entirely insane and overly complicated or maybe achievable? initial build is a workshop build.