thomas rubino

I planted the last sea berry today!
The first three have been in the ground for a few days, showing signs of new growth!
The male plant was the last one today and the farthest along of them all.
We plan to get three more starts from a lady in Spokane, two more girls, and another boy.
We also hope to buy berries from her this fall.

Hi Eloise;
I would not go any larger than an 8"
Stove pipe is easily acquired in 6 or 8"
I would build a 6" or a 7" batch in your guest house using an 8" exit chimney.
Once you warm your bell for the season, it will never cool down completely until spring.
With a similar climate here in N.W. Montana, we almost constantly have windows cracked open, even overnight; the masonry is that warm!
Remember, you can add a second load or even a third in a 6" if it is nasty cold outside.
Most of the time, I believe a 6" would keep you very happy.

Once warmed up, the big Walker cookstove would do the job, but you would have to add wood more often.

No worries about a sidewinder, they work every bit as well as the traditional rear exit.

Thank You, we are very proud of and very happy with Shorty.
The tiles are on a split firebrick roof that is supported by superwool-wrapped angle iron tees.

Hi Eloise;
After a lifetime of heating with a metal box stove, it is tough to envision heating with a brick/ cob mass.
My wife resisted for three years before relenting and allowing me to remove the old steel stove and build a Batchbox Masonry stove in "her " house.
Now she is their biggest fan!

Your home will be equally warm throughout. It is truly amazing to have 500-900 brick/ cob bell sitting in the living room at 80F—200+F.

The most significant difference between a 6" and an 8" is the size of the firebox.
ISA numbers are the maximum bell each size can heat without using a bypass.
Every build should include a bypass, even if undersized on the ISA.
You can burn more than one load in a Batchbox if conditions warrant it.

As far as having a window.
Look into building a sidewinder version of the Batchbox.
The entire core is turned 90 degrees, and the entrance to the riser is in the side wall rather than the end wall.
This should allow the door to face the sitting area.


My single wall 6" Shorty core weighs apx #2500
An 8" double wall could go over #6000
Your floor is already built extra stout.
You might add a few extra concrete pier blocks that could "catch" any sag that might occur; I doubt any will.

Well, Our home style is early American rustic...
A better description would be a 95-year-old log cabin with 60 years' worth of additions.

Hi Eloise;
2300F Fire Bricks will work if they do not offer a higher rating.

Here are some enlightening threads that you might like.
This one explains what a bell is,   https://permies.com/t/270559/Stratification-chambers-Bells-explained
This is my outdoor kitchen using Matt's core, the same size core used in the tiny cook stoves.
https://permies.com/t/164923/rocket-ovens/Build-Black-White-Rocket-Oven
This build might be an option for you as it holds heat for quite a while.
This is the Masonry stove I built in our home this fall.
https://permies.com/t/267527/Shorty-Core-bell
This one has good feedback from my rant.  https://permies.com/t/271647/build-RMH
https://permies.com/t/270178/Montana-Masonry-Dragon-Living-Room
https://permies.com/t/273010/Early-Morning-coffee-Shorty
https://permies.com/t/273139/Building-bench-heat-transfer-adjacent
This last one is an incredible build from a first-time builder; Glenn did an outstanding job of building and documenting his build.
https://permies.com/t/238503/Batch-Rocket-Build

Well, that should keep you busy for a while.

Hi Eloise;
Please do not make any changes to Matt's core design.
Also, please do not change one of Peter's batchboxes.
These designs are optimized to be ultra-efficient, any changes you were to make could have a substantial detrimental effect.
Without the high-dollar testing equipment, you cannot know what your changes may have done or what is coming from your chimney.

The firebox on the tiny cookstove is very small, and since you are in Alaska, I suggest building one of Peter's Batchbox designs.
It is a much larger firebox with a substantially longer burn time. Your guests will like it very much.
It is much simpler to build than the tiny cookstove.
The core assembly either sits flush with the bell or partially extends from the bell, giving you a nice hot flat spot for heating a kettle or even stovetop cooking.
The bell can be any shape that fits in your home.
We can help guide you online.
I also offer hard-copy books or PDF files on constructing Peter's design. These will help you to better understand the steps required to build a batchbox.
( https://dragontechrmh.com/)

Yes, you can safely make accurate cuts by first soaking any brick (clay or cement) and using a 10" diamond masonry blade.
An abrasive masonry blade can also be used on a hand-held side grinder for quick cuts.

Can you buy 2500F + rated firebricks in your area?

Yes, I know of a pending 7" Shorty being built this summer in Iowa.
Peter has built larger Shorty's in Europe
Peter can supply you with dimensions for a 5",7" or 8" Shorty.

You can use cob for the walls as long as you have either firebricks or CFB for the core.
What were you thinking of using for a top?  Salvaged oven glass, perhaps?  Or an old cast iron wood cook stove top?

I do have a preference for construction.
Unlike Matt, I am a fan of using the heavy firebricks. They do take time to warm up.
CFB is easily abraded while loading wood but has no warm-up time when starting.
Matt uses an expensive RA330 high-heat sheet metal liner to protect his.

With firebricks, you will always need to use the bypass to start a cold stove.
Small fires near the secondary riser tube are used to start the draft; it often wants to smoke back into the room until heated. (you quickly learn to deal with this)
Once heated, Matt's stoves live up to the RMH name, and the heavy bricks will hold heat for quite a while.

A CFB core is easy to start and comes up to cooking temperatures rapidly.
A bypass is still used to warm the outside chimney but is closed off quickly.
A CFB core will lose any heat rapidly once the fire is out.

Cutting bricks is way easier than it might seem.
https://permies.com/t/261066/cut-Brick-RMH

The pumps are working, and the Black and White is still under power!
The list is almost all gone!  
My cheese is no longer in danger of sliding off!
This is as good as it gets. I will still need to do some repair work, but it can wait until 2026 before making it to the top of the list!

Hi Eloise;
Great video!  That is going to be a really nice cob house when it is finished.

4" of cob is enough for walls.
Split 55-gallon barrels are often used to bridge between walls and covered in cob.
Cattle panels and hardware cloth can also be used.
A large sheet metal box can be made into a bell, covered in whatever material you find attractive.
Cob walls bridged with stone.
Cob walls covered with wood.
Away from the core, all materials are acceptable to be used.


Were you thinking of using Matt's riser-less core plan for this build?