Wednesday, 31 August 2011

The ups and down of the potter's life

Today I was feeling bright-eyed and optimistic as I opened the kiln. Most of the glazes I'd used at least once before and I thought I'd learned the lessons from previous trials and errors..

But, as is so often the way, some pieces came out looking great, some were indifferent and one or two were a bit of a disaster. Murphy's law dictated that the carved piece I placed in the saggar, which I wanted to come out best, was one of the slight disasters! I knew that my satin-matt, orange glaze could be a bit runny, probably because heavy reduction in the saggar was causing the metal oxides in the glaze to flux more than normal. But I really didn't expect the glaze to run right off the bottom of the pot and weld the wadding to the base! Fortunately, I could remove it from the kiln shelf, so it might be rescued with some judicious use of the Dremel grinding tool. The other minor defect was some pinholing on a couple of pieces, which I suspect may be due to the thicker clay walls releasing more gases during the firing..I'm not sure how I can get round that problem, apart from applying the glaze more thinly, which may (I say, may, I don't really you?) allow gases to escape and any bubbles to heal over more easily. I have a feeling that I may have over-fired everything a little too, as I soaked the kiln for almost an extra half an hour. That was because cone 8 didn't seem to be fully over, and I was concerned that the glazes may not have fully matured..ah, hindsight is a wonderful thing..if only..

Having said all that, I was really delighted with the glaze finish on several pieces..the orange satin-matt glaze looks like being a real winner, I just need to understand how best to apply it. The upside of the glaze running alot was that it created some beautiful rust-coloured "waterfalls", pouring over and off the carved ledges. I was also very happy with the small jug, shown below, with an oak-ash ochre matt glaze on the has a different, slightly glossier ash glaze applied to the inside, which has also produced a nice orange blush in parts.

Well, at the end of the day, it was an interesting firing and I feel I learned a few more things. And that's what ceramics is all about; taking small steps each time, learning from the mishaps and mistakes, and gradually moving forward. Making pottery certainly teaches you about patience and stoicism..but, despite the downs, one should never give up..the best is yet to come!

Glaze run-off under base of pot below

Carved vessel with satin-matt glaze. Reduction fired.

Carved vessel. Approx 2.5 inches tall.

Jug with matt ash glaze, approx. 5 inches tall.

Monday, 22 August 2011

Matt ash glaze: unpredictable and intriguing!

It's been a nice, warm sunny day today..just a few clouds in the sky and no rain at all for a change! So it was a beautiful morning to open the kiln and end up smiling at some of the interesting pieces which came out.
Most of the pots I put in yesterday were glazed with the same oak-ash, matt glaze I used on the little sake cup last time. I put a few pots inside the saggar with a little charcoal and the rest on the top shelf so they would fire in an oxidised or neutral atmosphere.

I find this glaze really fascinating, as the finish seems to be affected by a number of different factors. As usual, glaze thickness is critical and I discovered that one brushed-on coat simply isn't enough..that piece came out rather dull and patchy in appearance with barely any yellow in the surface, almost all dark reds and browns. Brushmarks were also clearly visible in places. What was interesting though, is that some pieces ended up being quite similar in appearance even though one was fired in oxidation and the other in reduction in the saggar. Another critical factor seems to be heat work on the piece and whether they are directly exposed to the fumes from the charcoal in the saggar. The more heat and fumes, the darker the glaze seems to get, to the point where it turns quite black. Most pieces have a yellow-brown-black mottled appearance, but one espresso cup has a really deep red-purple hue and the yellow areas have hints of green in them too (please see the first photo below).

All in all, this glaze is fairly unpredictable, but in a good way..unlike some glazes where they are unpredictable and their revelation is invariably accompanied by a deep sigh of tragic disappointment. I'm pleased with most of the pieces I pulled from the kiln today, and I'm happy that this glaze recipe provides a wonderful starting point for further experiments. Next time I intend to try layering a satin-matt calcium glaze over this ash glaze and see what occurs..I can't wait!

Espresso cup with matt ash glaze. Reduction firing

Oil pourer with matt oak-ash glaze. Approx 3 inches tall
Oxidation firing

Vinegar shaker with matt oak-ash glaze. Approx 3 inches long.
Oxidation firing.

Bowl with matt oak-ash glaze. Approx 3 inches tall.
Oxidation firing.

Espresso cup with matt oak-ash glaze. Oxidation firing

Wednesday, 17 August 2011

First tea bowl with an ash glaze!

I've only recently started using ash glazes, and this tea bowl was one of the really nice surprises from the last wood firing at Thoresby Hall. It was glazed with an oak ash glaze, and raw oak ash was also added to the rim. I was amazed by the dappled patterns and the deep yellows and dark purple tones, which blend together beautifully. This piece has really sparked my enthusiasm for trying out more ash glazes..I just need to find some reliable sources of different types of tree ash. My thanks go to Sue Mulroy who kindly provided me with a carrier bag full of oak ash from her kiln at Blackwell Farm in the Peak District.

Tea bowl with ash glaze. Approx 3 inches tall.

A 360 degree HD video of this piece is available on Youtube:

Monday, 15 August 2011

Matt glazes fresh from the kiln!

I tested several different matt glazes in the latest electric firing, and pulled out the results this morning. The oxidised satin matts came out rather dull with little surface variation, but I was delighted with this piece, which was fired in reduction in my saggar.

Carved vessel, approx 4 inches tall. Satin-matt glaze.

I've uploaded a video of this piece on Youtube: . This glaze contains red iron oxide and rutile, and there are even a few touches of rutile blue on the inside below the rim, just visible in the photo. I really like the way the glaze has run over some of the carved ledges, and the variety of yellow-orange-brown colours..also the way it's broken darker on the edges helps to define the form.

The next piece was fired in oxidation with a matt ash glaze. It's based on a John Jelfs recipe but I used oak ash rather than mixed ash, and marble dust instead of whiting. The thing I found amazing about this glaze was its' brushability. I only made a small sample, so I brushed it onto the outside, and poured the glaze inside. It applies incredibly easily, leaving practically no brushmarks..I'm wondering if the marble dust helps in this respect, as it's so finely ground and may help with suspension. Only two thin  coats were applied, which has allowed the body colour to burn through as a dark red-purple. The first piece was fired in oxidation, the second in reduction. Why is the glaze fired in oxidation more matt, I ask myself? Maybe because iron acts as a flux in reduction?

Small cup, approx 2 inches tall. Matt ash glaze

Carved sake cup, approx 2.5 inches tall. Matt ash glaze.

I'm not sure whether I prefer the oxidised or reduced ash glaze..they are both attractive but in different ways.

As is so often the case, there were some disappointments when opening the kiln. I tried a new blue-lavender glaze, which should have come out a bright glossy blue with satin lavender speckles where thicker..I had already tested it and it worked perfectly, but on the actual work I glazed, it came out a light blue-purple colour with practically no lavender speckling. Quite pleasant in itself, but not particularly interesting to look at either. Basically, it wasn't applied thick enough, which really surprised me as the glaze looked fairly gloupy and I dipped some of the cups twice. I think I need to re-test with a thicker glaze slop, and next time, measure the specific gravity..then ensure it's accurate each time I use it.

Update: I went back to the glaze today to give it a stir up, and the ingredients had settled into a rock-hard layer at the bottom of the took me a good ten minutes to get the whole mixture moving again. So I decided to mix in some bentonite and CMC into the slop to help suspend everything, and now it's looking thick and creamy; so much more useable as a glaze. It's pretty difficult to mix these suspending agents into the glaze once the other ingredients are wet. It took me an hour or so to get rid of hundreds of lumps with a hand blender..definitely not recommended. Hopefully worth the effort though..I'll post the results of the next firing with this glaze.

Mug with blue-lavender glaze. Approx 4 inches tall.

Sunday, 14 August 2011

Latest carved piece

Carved vessel, approx 6 inches tall. Unfired clay.

Today I carved three vessels which have been drying out for the last five or six days. The weather has been so wet and damp lately, that nothing is drying out unaided..the pots I threw three days ago are still soaking wet! Such is the good old British summer; sunny and warm one minute, pouring with rain the next.

I find carving clay quite a zen-like experience as it requires complete concentration and a calm state of mind. One careless slip and the knife goes straight though the wall of the piece, and it's ruined. At the moment, I am mainly throwing vessels on the wheel and then carving them, but this is restricting the size of the piece I can make, and the extent to which it can be carved into shape. If the piece is made from a solid block of clay, it allows more freedom in shaping the vessel, but is far more time consuming and uses up enormous amounts of clay.

Wednesday, 10 August 2011

Carved vessels..a new, creative direction.

Recently, I've been carving more of my ceramic pieces, something which developed from creating Japanese-style footrings for tea bowls. At the same time, I was interested in finding ways to give the surfaces of my pots a more rock-like appearance. I'm always impressed by the work of some Japanese artists who manage to fashion pots which look as if they have been sculpted from stone rather than clay.

Here are a few examples which were fired in the electric kiln last week. The first piece was glazed with a carbon-trap shino which has crawled hugely, but I am still pretty satisfied with the result.

Carved vessel, 2.5 inches tall

Carved vessel, 4 inches tall

Carved sake cup, 3 inches tall

New work from the last wood firing at Thoresby Hall

I am currently a member of the Sherwood Forest Wood Firing Society. The latest firing took place at the end of July and everyone seemed very pleased with the results from the kiln. Cone 10 was down although not completely flattened this time, and most of the glazes were fully melted. Many of the pieces came out with wonderfully deep fire colour and beautiful flashing from the flames and ash. Below are three of my pieces which I was especially pleased with.

Coffee mug with oak-ash glaze

Tea bowl with shino glaze

Twisted vase with shino glaze

Earth Work is launched...tannaaaaa!

I've finally got round to creating a new blog which I'm planning to use as a kind of  day-to-day notebook, recording developments and new directions in my ceramic work, as well as documenting any interesting events I get involved with.

I'm hoping that this may also be a way to connect with other ceramic artists around the world. The internet has already provided me with a huge amount of knowledge and's quite possible that I would never have developed an interest in Japanese ceramics without access to the www. 

Well, I'm looking forward to the challenge of learning to use this blogging software..I'm really hoping it's more user-friendly than the last editor I used, which could be infuriating...