Phil Stevens

I make small batches of biochar in my wood fire in stainless steel steam table pans. Sometimes I fill one with shells, crushed limestone or bones instead of wood chips and nut shells. The temperature inside my fire is around 600 C when it's got a lot of coals in there, so that will definitely calcine the feedstock and I get decent quicklime or bone char as an end product.

Can you get your hands on some hessian (jute) fabric? I plan to start making bags out of this stuff and filling them with biochar for sediment traps which will also grab soluble nutrient loads from waterways.

I use cabbage tree (Cordyline australis) leaves. They are amazing. Newsprint, especially if it's got a bit of grease on it, is also reliable but has the ash problem if you use a lot of it.. If you have some fatwood (pitch pine, ocote) and can make thin kindling from that it will not only light easily but also burn hot for long enough that you can get some larger diameter fuel in the mix.

Looks like Lamiaceae, mint tribe. Could be a basil...gotu kola?

That doesn't look like it's designed to sample hot flue gases. It's an ambient CO detector which would be worthwhile if you were heating an indoor space with a RMH and you wanted to assure yourself that it wasn't leaking or backdrafting.

Peter van den Berg would be the definitive authority on what sort of analyser is worth getting.

Yes, it sounds like thermal gradients did it in. You need to use something more robust than terra cotta. The stone you used was probably intended to go in a convection oven where it would heat more or less evenly, not atop a combustion tunnel with 1500 C gases hitting in a small area.

Firebrick splits are the go-to for pizza ovens, and cast refractory "stones" are another option.

Dane. the temperature required to "reactivate" plaster is quite low. I've done it at about 150C on top of the wood fire. All you need to do is drive off the water, and this works for stale plaster that has been sitting in an open bag in humid conditions as well.

However, it is a great soil amendment for increasing Ca without raising pH. Go nuts with it.

This is the source for the cone kiln: https://www.ithaka-institut.org/en/home

The most common type of woodburner in NZ is a steel box with fireboard inserts and controlled air intake. If you did a survey on all the homes heated with wood in this country, you'd find a lot of old Kent fires and similar. Clean air regulations introduced since 2000 now limit wetbacks and slow-burning designs in urban areas, but on sections over 2 hectares in rural areas there are no restrictions.

I've lived here since 2005 and have never seen or heard of a "double burn tile fire."

Thanks for the thoughts. I have a couple of pilot sites in mind and a mate of mine had all the pine on his farm cut down last year, so things are about to click. As Kola Redhawk says, this is a politically opportune moment to get the local and regional councils looking at a biochar solution, as the central govt is reviewing the freshwater standards and is likely to tighten them considerably (the last one relaxed them so much that they are more or less a joke). So funding might be easier to get.