Benen Huntley

We tried for 4 years to grow good vegetables and had very poor results. Last September we built a greenhouse with roughly 30sqm of growing space. Since then we purchase almost zero produce. I can't recommend it enough.

Definitely will do. Here's the core. Have plenty of blanket to make a 5 minute riser.

Hey all,
Time for a new project. I used left over firebrick from my indoor batch rocket heater to build a 4" core.
I was thinking I could build a nice little efficient outdoor stove or oven for cooking soups, stews, stocks etc rather than leaving the induction cooktop on for many hours.

Any suggestions on designs that are tried and succesful?

I have a lot of clay bricks also so I thought about adding the exterior of the core in them, leaving a gap and filling it with perlite to insulate. Then building the brick up into some sort of small oven that fits a large pot or a cooktop...

It looks beautiful and fits in great with the earth dome. I hope you're proud!

Glenn is correct. It is discussed on Peter's batch rocket site batchrocket.eu on his most recent build. To simplify the build they did a square riser with only chamfered rear corners up to at least the height of the port.
He reported that performance was at least equal with an entirely octagon riser I believe.
I have made a 5" system for a friend this way recently.

I have been a part of two wood heater saunas. The second was a small sauna with a 4.5" batch rocket. The thing cranks to 130c with that heater. We find that between 65c and 80c to be a good balance so it is more than enough power.
Yours is a lot larger but I would think even a 5" would do the job.
Adding mass will cause it to take a very long time to heat so I would advise just using a barrel with some rocks on top. That way you can still use water on the heater but get instant heat when you light the fire.

I'll give a strong recommendation for a batch rocket. I'm biased, having never built a j tube. While I agree that the j tube is simpler to build, I can't say I found the batch rocket particularly difficult to construct. I was offered plenty of excellent and prompt advice here at permies and took my time and I'm very pleased with both of mine.

It's alive! Still drying the bell but burning smokeless and the house rose from 10c to 20c quite quickly. The other side where the bell is got up to 30c quickly and I can't touch the top of the bench. Water steams off immediately.
Need some shielding behind the barrel urgently as the wall is getting very hot!
Couldn't be more pleased!

Picked up the glass for the door today. All that's left to do is the cowl and dektite on the roof, get the glass in the door and drop the bell over the riser.
Was hoping to have it firing tonight but I can't lift the bell alone.

Nearly there now! Monday the flue will go in and tomorrow some paint.