04 January 2009 - My pots have been sitting on the windowsill, unfired now, for months. Time to get firing...
Before You Read On
I have no intention of wasting the reader's time, so let me begin by stating: The firing was a total failure. Nothing resembling a pot was produced.
What Happened?
I put my single-use kiln on my now-bare vegetable patch and filled it up with dry pieces of timber and twiggy material.
I dug a small hole underneath each of the air vents, to promote airflow.
I carefully nestled the pots into another layer of twigs on top of the main load, then covered them over with more small pieces of wood.
I crumpled a sheet of newspaper into each of the vents, then lit them.
before long, it was burning quite fiercely with an audibly roaring flow of air and very hot flames leaping six feet or more from the open top. The damp fence panel four feet away began to steam and had to be doused with water to prevent risk of it catching alight,
For half an hour or more, it was impossible to get close to the fire. The embers inside were white hot.
Eventually, the fire began to burn down and it collapsed very slowly, gently and gracefully into a heap of small, very hot embers.
I left it like that for another half hour, then couldn't resist gently raking away some of the top embers to see if I could catch a glimpse of a pot...
Nothing.
There was nothing there.
There was no trace of any of the pots - not even broken pieces.
After a very thorough search, I did find a few chunks of crumbly reddish stuff - which may be part of one of the pots, or might just be pieces of garden soil that got baked hard by the heat.
What Went Wrong?
Difficult to be sure, but I think my fire got too hot, too fast - I think this may have surface-fired the material, then caused the clay to pass too rapidly through one of the critical heating phases (during which it may expand abruptly), shattering it into small fragments.
It's also possible, I suppose, that the clay just wasn't as good as I thought - maybe it had too much organic material in it, or just didn't have the right chemical composition to make it worth firing.
What Next?
Well, I still have about half of the clay left - I could make some more pots and see if I can find a proper kiln to fire them in, or I could do some research on building a proper wood-fired temporary kiln.
I'm not giving up, but I'm not going to try to muddle through another attempt at this on my own. Clearly there's essential knowledge here that can only be learned by lots of trial and error, or from someone else's wisdom and experience.
