Thanks for the input Glenn, You are absolutely correct about the steady and low temps at the start of the firing cycle.
I have already tried an L-Shaped rocket stove, made out of firebricks, held together with clay. This rocket had a small chamber for pots etc...on my first attempt I lit a small fire and then continued to stoke it. Within about 1 hr, I heard the familiar "popping" of the clay pots.
On my second attempt, I started small fires with cardboard and paper, each hour for 4 hours until things started to heat up. I think I still fired too quickly as although the pots survived , looked like they had vitrified and sounded like ceramic when I tested them, some were grey in the middle..I forget the name for this, but means it was fired too quickly and not enough heat work.
The small Kiln was then destructed and I built a new chamber for a Weed Burner on propane to be the heat source. Similiar to a raku kiln, but with firebricks on the outside and ceramic fibre on the inside. This also heated up too quickly, but was certainly more controllable. I actually managed to bisque and glaze some earthenware pots with this. Although I ran out of propane very quickly.
I think my intention would be to have propane burners incorporated into my design, to allow for slow early heat up to around 400 / 500 Celcius and then use wood. I love the look of wood fired pots and would expect each firing to take 24-36 hours.
I would use modern materials to retain the heat within the kiln.
I would also like to avoid that black smoke each time the firebox is loaded. With this in mind the best options are gasification (pre heated secondary air), complete combustion and the bourry box is an excellent example of achieving this.
I have also experimented with TLUD Gasifications stoves (small ones, made out of a SS flue section) and they didn't smoke at all, I might even put one of these into the firebox at early stages to slowly heat the kiln up to temps. Only issue with these is that once the fuel is in, you cant add more, easily.
I wanted the ware chamber to be approx, 2ft x 2ft x 2ft, the firebox would be similiar size or larger. I did run out of stoking room on the first wood kiln, but mostly from the embers building up.
Dont know if my vids will work:
Fire Kiln, in Oxidation - Just make out the blue flames here, didnt have a temp gauge, but think around 800 celcius
Video- Oxi
Same Kiln in reduction (i Think)
Video - Reduct
Would love to trial build this and have some input into this, before committing to the cost of the modern materials.
Maybe a clay brick built one without all the insulation etc would let me know if its gonna work.
Anyone have any experience of Fast Fire Kilns, such as Olsen Fast Fire Kiln, this one is pretty much a L Tube Rocke Stove on a large scale
