MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
The kids found some clayey mud in the local stream and made pots, so I thought we could try firing them in the chimenea. Tried last night (burning wood also from the local woods!) and the test piece came out generally ok. It got red hot in the fire, and it now sounds like terracotta when tapped which is good.
So the next task will be to see if I can glaze it, again just using 'found' materials rather than buying supplies. Apparently I can use ash to glaze it, presumably painting on some kind of paste; or I can use salt by simply soaking it in brine. We're near the coast so I am going to assume that brine counts as a local material 🙂
The challenge will be getting the chimenea hot enough, it needs to be more than dull red I think - but I can easily do a better job on the fire than I did last night.
From watching the Pottery Throwdown, I know that glazes are mostly the non-coloured bit, so I'd imagine youd need to find out what makes that up first?
Of course you can use a slip, but that isn't shiny like a proper glaze, as glazes have silicon/glass in them I think, that melts to give the shine, and glass melts at what, 1500deg+ ?
I read the title as 'Experiments in poultry'.
😀
A salt glaze or ash glaze might get results and should be a fun process
Salt glazes finishes are from adding to kiln at when at high temperature and the salt has a chemical reaction with the surface of the pot. I think if does not get hot enough it wont glaze, not sure if it would still change colour but wont get the salt glaze finish
An ash glaze is a bit more hit and miss on finish and is more experimental depending on the temperature you reach and the type of ash you put on the reaction will be different. You will get a colour but finish is impossible to predict.
If you have tongs you can also put a hot pot on anything combustible e.g. staw, hair.. and will get random reactions, wont be a glaze but will add colours and pattern
If you can force air in e.g. leafblower then can get really hot to get the chemical reactions going but not always controlled! probably risky in a chimera but a metal bin should be ok.
A traditional glaze type finish is probably not achievable both from getting materials locally and also getting a high and controlled temperature
Would be interested to see results
They're always going to be brown tbh. I'm more interested in making them water-tight, if I can. I am fairly sure finish is going to be awful. My eldest is more interested in the primitive/bushcraft side of it than anything artistic.
We might do it again, this time we'll try and really smooth the pieces down with hands and wooden implements etc
How do you apply ash? Painted on as a paste?
Metal bin is a good shout, didn't think of that, and a fan of some kind. I was thinking maybe making something out of bricks and using holed bricks as a platform. But that moves slightly away from the really primitive aspect. Maybe next time.
Achieving a waterproof glaze requires a very high temperature. You won’t be able to do this without using kiln insulation materials, or burning a vast amount of wood in a brick kiln.
It is perfectly possible to achieve stunning visual results using a pit firing method. I do this in an old oil barrel with holes in the bottom sides. Fill with large wood, layer pottery in the wood as you go. Start fire at the top once full using a big pile of kindling. Once the top layer is a roaring fire and starting to burn down, place a piece of metal on top to almost seal the barrel. The idea is to shut off almost all of the oxygen, but only when the fire is hot enough. The fire will continue burning for at least 12 hours.
In terms of decoration, I use copper wire, horse hair, banana peel, salt, any organic material I can find. Either scatter around the pots, or glue to pots, or wrap pots in foil and place inside foil.
Some of the pots will explode, so make spares. Get them as dry as possible before firing.
If you have your heart set on achieving glaze temperatures, it is quite easy to do so using ceramic fibre. I have achieved 1300 degrees in a couple of hours using a £20 weed burner and one roll of fibre. I use the rocket kiln design on this page. http://www.ian-gregory.co.uk/kilns.html
if you are after a glaze finish rather than anything decorative then I think a salt glaze is probably the best thing to try. Salt glazing used to be used for things like drainage pipes so is low tech and robust. add salt once hot, I think water content and impurities are what gives different finishes.
ash can be applied mixed with water or dry, it will not make waterproof, it is more about decoration. results will vary depending on temperature and air when burning
the outcome of any pottery using fire or natural glazes will be about luck and unrepeatable, enjoy the process and you may get something cool out the other end
This is awesome, speaking as an occasional potter. (no advances in the answers above, I do my stuff in a studio).
Wood ash is worth trying, look online for recipes.
I wonder how hot I can get my chimenea, given a bit of thought.. It might destroy it.. but it was a cheap one!
Reading about ancient glazing techniques it seems that glazing is relatively new compared to the invention of pottery, so people must have been able to seal pottery before glaze. I thought of using fat or oil and baking it on, like seasoning a cast iron pan or that gunk you get stuck to your cooker hood (or is that just me?) which is polymerised from the oils, and apparently this was done in ancient times.
I was half way through a pottery course when Covid brought an end to everything. From what I remember, the glaze does not provide the waterproofing, it is the firing. The heat is so extreme it melts the chemicals in the clay.