Creating texture on inner and outer surfaces of your pottery/Part 1-using a stamp

Clay is wonderfully pliable, which is why I and so many others are so hooked on it. In some of my previous newsletters I have written about using glazes to create colour and pattern. If you want a quick recap you can find these articles in ‘A Potters Journey’ on my blog.

Textured clay works fantastically well with a glaze, no need for expensive or complicated gadgets here, the simplest of found items can be used to create detailed and intricate patterns. All you need is imagination and patience.

The following  technique is widely used and is straightforward,a simple method of creating texture and detail by using a ready-made stamp to emboss the surface. Wooden or rubber print blocks work equally well.  I’ve used a Vietnamese good luck stamp on some of my salad bowls. It wasn’t intended for use on pottery, but I tried it out and loved the result.

A stamp can be applied directly or indirectly to your wares.  Applying a stamp directly can be complicated, and there is a risk of distorting your piece or weakening the wall.  In the case of my Vietnamese stamp, I applied it indirectly.

Roll out a thin slab of clay, turning it over from time to time, so as to prevent it from sticking to the work surface and rolling pin.

 

Now cut the clay slab to sizes, enough for a few stamps, dip the stamp into cornflower to stop it from sticking to the clay and roll the clay over it applying slight pressure with your rolling pin or wooden dowel (using talc or other glaze materials for dipping your stamp is fine too and might create some interesting glaze effects).

 

 

Gently peel the slab of the stamp, making sure it doesn’t tear, cut it to size, place it on the pot and gently mark around it.

Now put your stamped clay aside, score the area within the markings on the pot and apply slip to it and the back of the stamped clay. Reapply the slab and join it to the pot by very gently tapping it from the centre outwards in all directions. . Be sure that the edges adhere tightly to the surface of the piece, so that the ‘stamp’ doesn’t peel away during drying and firing, remove any excess slip from the edges with a small paint brush or wet finger and carefully smooth the area.

 

Advertisement

Glazed & confused

The only way to learn about which ceramic glazes work for you is to test them. The idea is to study what happens when you mix various amounts of various ingredients in a glaze and fire them to various temperatures. It’s about understanding how different materials affect each other in order to be able to achieve the results you want, and to troubleshoot when the results are really not what you want.

Sounds confusing? Well yes, and certainly not great for those of us who avoided chemistry at school because, in essence, this is known as ‘glaze chemistry’ which is complex and at times intimidating.

Recently, I was working on blending some new colours into my wares, not just new colours but new applications – white with a yellow stripe, white with a purple stripe and several others. I bought some new commercial stains and glazes in the colours I want, and experimented with them. I tried several glazing tests and methods:

1. A) Mixing commercial stains into engobes, as I do with colouring oxides.
2. B) Mixing stains into my own glazes.
3. C) Using coloured commercial brush-on glazes over my own glazes.
4. D) Using low-temperature glazes over a high-temperature matt glaze in the hope that they would run down and blend into the base glaze.

So far, I’ve had very limited success with these tests. In general reds do show up, yellows disappear or come out faded at best; and the colours stay put, they do not run down the sides of my pots

I’d like this tale to have a happy ending, but I’ve not yet solved this chemical conundrum. However, I must emphasize that it’s vital to keep all test results. Even if they are not what you’re looking for at the time, this little bit of research may lead you to what you are looking for later on.

Also, my quest for a solution to my glazing problems led me to a website which aims to make glazing chemistry more like glazing cookery, with all recipes tried , tested and available at the click of a button. Who knows – I might be uploading a recipe of mine to this collection quite soon?! http://ceramicrecipes.org

The wonderful world of glazing

When it goes well it’s wonderful, when it goes wrong it’s anything but…
In past newsletters I’ve touched on some pottery basics – clay, turning, firing, and even glazing. But my glazing skills have really been put to the test in recent weeks as I grapple with trying to work out new methods for my current project. What might seem straightforward in the world of colour is extremely complex in the world of glazing.
The glaze is the final layer, the coating that fuses with a ceramic item in firing, intended to colour, decorate, strengthen and waterproof that item. As a rule, glazes can be classified into two types: those that are fired at low temperatures – up to 110° centigrade – seal and waterproof the clay, and are also decorative; and those that I use, fired at high temperatures – at least 120° – which are absolutely impermeable, amalgamating with the surface of the clay to improve the quality of the finished article. They also have a strong aesthetic element. I prepare my own glazes, and they are what give my pottery its unique character.
Raw glazes are compounds of silica, minerals, and metal oxides, and are applied in various ways, mainly by dipping the item into a glaze solution or by applying it directly, either with a brush or by spraying.
That might sound straightforward, but a lot can go wrong:
If the firing temperature is too low, glazing will not be uniform, and if it doesn’t fit properly, it’s like a badly made item of clothing – too big or too small. If the firing temperature is too high, the glaze will run.
If poorly applied, the glaze will blister, be uneven, and can also fail to adhere.
Incorrectly mixed raw materials can cause crystallisation or air pockets in the main body of the clay;
and lastly, there are kiln accidents – items stick together, power cuts create havoc, and small pieces of debris cause imperfections.
Essentially, patience and determination are what you need. Good work is often lost when experimenting, but when you finally get it right – it makes up for everything.

Time to put a lid on it…

In a recent newsletter I briefly highlighted the art of throwing, so I thought it would be good to continue with a little more technical information, this time about lids. When it comes to making a pottery lid that fits – it is an art that one masters over time.
There are several types of lid that are used when throwing pottery. Apart from being a focal point of interest, lids require a certain amount of consideration.. You need to create a lid that fits the pot both actually and aesthetically. If the pot is a functional piece such as a casserole, the lid must also function as efficiently and effectively as possible. The main lid styles are:
Cup lids- the earliest and simplest form – they ‘ride’ over the outside edge of the pot
Inset lids- that sit on an internal ledge formed when throwing the pot.
Domed lids- also sit on an internal ledge or with a seating on top of  the rim. They tend to be elegant in shape and stronger, so are good for larger pots.
Stopper lids-similar to cup lids,  but the entire lid sits inside a V-shaped neck and acts as a stopper
Personally I make and prefer the domed over-edge lid. I make sure it fits well and barely shifts on its seating, and I like it to extend slightly over the edge of the pot, especially if I’m making a casserole. It works very well for teapots too!
I often combine a flat inset lid style with the seating of a domed over-edge lid, which makes for a very good fit. Occasionally when I make small lidded jars that are cylindrical, I use a flat inset lid with a knob on top – nice and simple!

The art of ‘throwing’

You need much skill (and experience) to throw pots that achieve an acceptable standard and have high artistic merit.
During the process of throwing you turn or twist a ball of clay, gently pulling it upwards to create a hollow shape. You do this by placing a ball of clay in the centre of your turntable, which you then rotate. The trick is to press down on it in perfect rotational symmetry ( knows as centring the clay) , it’s probably the hardest skill to master as a potter, but necessary before taking the next steps. When you’ve mastered centring, you will be able to progress into opening – making the centre of the ball hollow; flooring – which ensures that the inside of the dish is flat or rounded; pulling – which shapes the walls to the right height and thickness; and finally trimming or turning which removes excess clay, refining the shape and creating a foot if necessary.
You can then further modify your pieces by attaching handles, lids, feet and spouts.
My experience of teaching pottery-making has taught me that, generally speaking, four to eight sessions are needed in order to learn centring properly, another four to six sessions to learn the basic techniques of opening, and the same again for pulling.

Ben Boswell Photography

Photographer Ben Boswell picked up a camera while still at school, and what started off as a hobby became a way of life. In the early 1980s his interest in crafts, especially in ceramics and pottery, paved the way to photographing some 30 of the most influential potters of that time. The catalogue of images, which is as beautiful as it is impressive, includes Phil Rogers – salt-glaze and reduced stoneware specialist whose work graces museums worldwide; David and Margaret Frith – husband and wife team amongst Britain’s most respected and world renowned potters; David Leach OBE  – son of Bernard Leach ‘the father of British studio pottery’ – who subsequently managed ‘Leach Pottery’ and others as far afield as Japan.  As is often the case, family life took precedence, and in 1982 Ben began selling professional photographic equipment.  For almost 30 years his beloved ‘potters project’ was shelved. Now he has returned to the project with renewed enthusiasm, loves every minute, and is working on publishing a book too. Apart from his website which catalogues his extensive body of work, Ben now has a FB page, regularly updated with both current and catalogued  images, providing fascinating and invaluable insight into potters and pottery alike.

FEATURED IMAGE:
David Leach Fluting a bowl during a demonstration at a craft camp in the late 1970s
By kind permission of Ben Boswell

Welcome to a world of colour, the glazed kind

Glazing is one of the most frustrating aspects of making pottery, but once mastered it is also one of the most rewarding. Ultimately it is necessary to use metal oxides, stains, underglaze decoration, commercial or self-made glazes, and in some instances overglaze enamels and lustres in order to give your ceramics colour, depth and complexity. Colour gives pottery an identity that, in many cases, can be even more obvious than the identity achieved through form.
Glaze mixing and testing is complicated and often involves a lot of time and effort. Not everyone has the interest or inclination to delve into the complexities of chemical and mathematical formulae.  Most potters, even those who can mix glazes, use commercial glazes or underglazes to some extent.  What’s more, commercial glazes are also screened for toxicity, which makes them safe ‘liner’ glazes for foods.  The range of commercial glazes grows constantly, adapting to ever-changing trends and offering vibrant new colour selections, a great indicator of what the market likes and an opportunity to be brave and experiment with new colour
Decoration applied beneath a glaze in pottery is known as underglaze. Underglazes can be applied by brushing, pouring, dipping, spraying, sponging – pretty much anything goes. They add colour and depth to your work, and are ideal for detailed decoration.  Another option is to use clay slips or engobes, which are, in fact, ‘runny clays’ with added colouring oxides or commercial stains. Slips are used on the bare clay whilst it is still wet or damp, and their colours bleed into the glaze when fired.
Lastly, potters use what is known as an overglaze enamel or lustre, applied on top of the glaze and then fired at low temperatures. These are generally  used as for decoration..
Personally, I tend to use spirals or texturing as the background for decorations. I either use glazes that emphasize these details, or engobes that are actually integrated in them, and then apply a glaze that will seal the item and make it food safe while giving it an overall colour. I mix all my glazes, some from my own recipes achieved by trial and error, and others from books that I have slightly modified to meet my needs. I choose colours that, I feel, suit my shapes and look equally good on the shelf or on a plate with food. My signature glaze is, of course, my blue glaze, which I use on its own or combined with white. It reminds me of the Mediterranean Sea in spring or at the end of summer, and since I created this one myself, I feel that this colour is me, in a nutshell.

Something about clay

I know some of you wonder whether I spend my free time digging up the back garden to get clay for my pottery. I guess it’s time to get the record straight and give you an insight into clay in general and more specifically the clay I tend to use.
Not quite as exciting as digging up my own clay, I actually order ready-made clay and have it delivered! Even better, if I’m not here when it arrives I leave a key and find it neatly arranged inside the entrance of my workshop when I get back.

‘Clay’ is short for ‘clay minerals’ which are formed over long periods of time by the weathering of rocks, and is often found around large lakes or marine basins. It is a deceptively simple material, cheap and abundant. It is soft, pliant, plastic and impressionable, without grain or direction. It can be modelled, pounded, flattened, rolled, pinched, coiled, pressed, thrown on the wheel, cast into moulds… you name it. It can be made into works of any size and unfired clay can be crumbled, mixed again with water, and made into something else.

Firing clay changes its chemical composition for good, and converts it into ceramic material. Fired clay may be white, creamy, red, orange, yellow, grey, brown, black, speckled, streaked, translucent, textured or smooth, porous or dense like hard stone.

There are three main types of clay – earthenware, stoneware and porcelain. The difference is in their firing temperature, the strength of the fired material, its colour, density, or translucence.
Earthenware is low fired (up to 1100 degrees centigrade) and can be quite porous.
Stoneware is high fired (1200-1300 degrees centigrade), is vitrified, and can be as dense as hard stone.
Porcelain is usually dazzling white and contains elements of glass in its composition, it is normally used thin, is high fired, and can be translucent.

As I have mentioned before, most ceramicists buy ready-made clays, packed as clay bodies – blends of natural clays ready to use and suitable for practically any specification, i.e colour, plasticity, texture, strength, firing range and many others.

I use stoneware clay bodies made in Europe. I prefer darker iron-bearing clays for use with my blue glaze – that’s how I obtain depth of colour; bright clays with less iron for my whites – that’s how I get a clearer colours.

Firing it up, Anagama style

This month I have been able to place some of my pieces in an Anagama kiln belonging to my friend and fellow potter Meir Moheban

The Anagama kiln (Japanese: 穴窯 meaning cave kiln) is an ancient type of pottery kiln brought to Japan from China via Korea in the 5th century. It is a single chamber kiln with a firing box at one end and a chimney at the other. It is fuelled with firewood and requires a continues supply round the clock. Depending on the length of the kiln it could take anything from 48 hrs to 12 days.
A natural ash glaze is formed from the interaction of flames, ash and the minerals in the clay. The placement in the kiln also affects the glaze, those closest to the firing box get the most ash and are often covered in it whilst those at the back are gently coated in it. It takes as many days for the kiln to cool down as it takes to fire. In this instance Meir’s kiln was fired up for 7 days, it is now cooling for 7days and the big opening celebration is on Feb 2nd 2013. If you are around, pls join us for the kiln opening.