Matt Todd

Peter van den Berg wrote:

Matt Todd wrote:@Peter van den Berg  
Do you think it would be alright to put the final exhaust opening on the BACK side of the riser instead of the front?

Yes, Glenn is right, it can be done. The lower riser part should be different, the pictures of the French bench build are quite clear how it should be done, in my opinion.

Alright, so a simple matter of moving the "riser liner" to the back wall instead of the front. I was afraid that this decrease in port depth would have an effect on the design, but I see now that you have tested this and found it satisfactory. The flames still enter a square space to form the vortex before expanding in the wider top half of the riser. Thanks for confirming!

@Peter van den Berg  
Do you think it would be alright to put the final exhaust opening on the BACK side of the riser instead of the front?

I'm thinking of putting an oven on top of the firebox. Which would only work if the exhaust could shoot out the back of the riser into a bell.

J Katrak wrote:
I also need to figure out the best way to get some panels here first.

That struggle is real! On one purchase, I needed smaller pieces so I took bolt cutters with me the farm store and cut them to size there. That fit them in a pickup truck well enough.

On another purchase I waited until I had a trailer borrowed for something else and made good use of it by picking up some panels too. Tractor Supply rents trailers and sells cattle panels. Plus I think you get a free trailer rental yearly if you are a "member."

*edit* I see you meant "how to get them on your island at all" so sorry, a trailer is no help there!

I made an "arch" with something akin to the idea of tensegrity. I wanted an open front situation, so I made a 4x4 front frame, bowed cattle panels against it, and used metal cable to balance the pushing force of the panel against the wood. Holding up great and it's gradually being colonized by the native vines I've planted around it.

Looks like you're asking about lavender specifically. I grew about 3 dozen plants from seed last year with NO stratification! In my studying before, I found a lot of growers saying it was not necessary for lavender and indeed it was not for me.

I filled 6 pack cells with sterilized 1:1:1 Sand, perlite, coir soil mix. Sterilized because lavender seedlings are very mold sensitive. 70-80 degrees with light 16 hrs/day. They sprouted in about 7 days. Keep moist for about one month after sprouting (until roots are established). Pot up at 6 or more leaves.

Hatching chicks from an incubator (because my mamas will not brood.) Attempting to hybridize my old Rhode Island Reds with Speckled Sussex.

Also going to try to grow and harvest my favorite medicinal tea herb: Tulsi (holy basil.)

Happy to see no reports of cracking with the all brick (except ceiling) bell!
Funny that you did tile on top of the fire brick roof, that's exactly what I was thinking of doing myself.
Did you use sand/clay mortar of Matt Walker fame, or a purchased refractory mortar?

L Cho wrote: Barrels can be a little hard to find here, so I was thinking about fuel oil tanks, which can be had for free. If the tank can be cleaned/purged enough to be considered safe, can I simply adjust the value of internal surface area, ISA, by raising or lowering the exhaust port?

An old fuel oil tank is exactly what I used. A 300 gallon tank has just about the perfect ISA for a 7" core. DSR2 in my case, so it could slide in.  
https://permies.com/t/151576/Sherman-Tank-DSR-Rocket-Mass

This build is really making me question the conventional wisdom that says everything above the heat riser needs to be double skinned with a refractory (usually firebrick) inner layer.

I went on a deep dive to see what temperature red clay brick is fired at and across 9 sources 800C (1472F) was the minimum and 1200C (2192F) was the maximum.

There are not many sources for temperature readings inside a brick bell, but one well documented case on the Donkey32 board measured 600C (1112F) at the bell ceiling with temps dropping quickly down the bell wall.

While I would still use firebrick in the ceiling (out of an abundance of caution) I'm really seeing no reason to continue firebrick down the inner walls. Aside from the fact that firebrick comes in splits which helps save space to make a double skin.

I see you put a thermocouple in the riser. Did you happen to put one anywhere in the bell?