Should I make my own Pottery Glazes?

Coloured glazes used by Tinkling toadstools

This question has caused a lot of debate among potters. It is a similar question to "should I make my own bread, cakes or pastry?" Clearly there is no right and wrong answer. People who bake their own bread and cakes do so for numerous reasons. Whether it is to reduce costs or make it fresh or make it taste better; all are valid reasons. However most do it because they like it and the self satisfaction it gives them to create something of value.

 Similarly, the potter will often claim that making glazes gives him the same type of satisfaction, is cheaper and gives him more scope for creativity! But lets look at the issues involved in making glazes in detail to see if his claims are true:-

 Costs

Glaze materials

There is little debate that buying the glaze materials to make the glaze can reduce costs significantly. Common materials such as clays, felspars, silica, frits and pigments are all readily available from a number of suppliers. However, often they are not in the ideal form to produce a glaze without additional processing. Most need at least a number of processing steps to make a satisfactory glaze. These steps include, preparing a recipe, grinding or mixing with water, sieving, magneting, testing, and controlling the glaze slip consistency using additives. The time and knowledge to correctly process and test the glaze are mostly overlooked when cost comparisons are made. For those with time to learn about glaze materials and the process this is not an issue. However for many hobbyists who are time poor it clearly does not make sense economically.They are better using reliable commercial glazes.

Creativity

Unique copper ruby glaze

Without doubt making your own glazes is a creative exercise. Again using the same cake making analogy as before, you have complete control of the make up of the glaze and how it will look after firing. Just like cake recipes there are thousands of recipes for glazes each giving its unique colour, texture and appearance depending on how its fired. This uniqueness is what many studio potters strive for.  By varying the pigments and make up of the glaze in theory you can innovate to your hearts desire! Therefore creativity can surely be improved by making your own glazes!

Technical restrictions

In practice, however,  there is considerable science behind making acceptable glazes:

• The glaze needs to technically match the body or the glaze may just peel off like old paint. 

• There is a limit to the range of compositions that can be made- for example some recipes will just never make glossy glazes.
  
• The firing cycle and atmosphere have as great an affect on the glaze appearance as the recipe.

The fired glaze surface of functional tableware needs to pass the requirements of legislation e.g. toxic metal release into foodstuffs.

So if you want to be creative with glazes you also need to have some technical knowledge. Potters without a scientific background may struggle to understand these technical parameters and hence making glazes could ultimately become more trouble than its worth.

Health and Safety

Unleaded Glaze

In recent years this issue has grown in importance for potters making their own glazes. Lead, for example, is being phased out in commercial glazes and its use and safety has been severely questioned especially in the USA. Other materials such as Barium compounds need to be used within strict guidelines for safe use. Even pigments such as cobalt and nickel oxide have been questioned over their safety. Clearly there is a lot to learn technically to comply with health and safety during the making of glazes. These issues are understood by commercial glaze manufacturers who can provide up to date data sheets on the glazes they manufacture and supply.

Equally important is an understanding of the legislation that applies to the fired product to meet the demands of the end market. Functional tableware has to meet much more legislation than ornamental ware in the various countries around the world.

Summary

In summary making your own glazes safely and successfully is much more difficult than at first appreciated. Technical and health and safety issues are not easy to overcome. However for a potter or hobbyist with a scientific understanding he can indeed be more creative and lower some material costs by making his own glazes. For the uninitiated it will be a long road of trial and error and frustrations. For those determined to try I recommend you do some reading and preparation online or in the wealth of books available before you begin. 

Good Luck and Happy Potting

The Potters Friend

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend.

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The Wedgwood Collection and the changing face of UK pottery

Wedgwood Museum

Staffordshire pottery manufacture changed forever in the late 1980's and early 1990's. The power of the supermarket buyers, the draw of low cost manufacture overseas and the changing markets in Europe all contributed to the massive decline in pottery manufacture in the UK. So many big names like Royal Doulton, Spode, and Royal Worcester, to name but a few, now exist merely as brands with the factories closed and demolished. Bleak as it was for the thousands of workers who lost their jobs during that time, many of those workers still talk fondly of the friendships, skills and pride of working in the hundreds of potbanks which existed at that time in north Staffordshire and especially Stoke on Trent.

Staffordshire Oatcakes

It was not just  the potteries that demised but also the services to those factories, the engineers, the material suppliers and sandwich and oatcake shops that provided breakfast and lunch to the hungry workers at break times.For the lucky few they found work elsewhere and the humble Staffordshire Oatcake lives on mainly through online marketing and Social Media.

Many of those pottery workers now rely heavily on their work pensions created during their employment at companies like Wedgwood. However Wedgwood pension trust has a big pension deficit that is causing  problems.

Over the last few years the importance of this pension deficit has been highlighted as the struggle to keep the magnificent Wedgwood Collection at its home in the Wedgwood museum in Stoke on Trent continues.

For those who have not seen the collection I urge you to do so. You will not be disappointed. At over 80,000 historical pieces, ranging from early experiments for new bodies and glazes through to modern production as well as rare manuscripts and letters, pattern books, works of art and photographs, covering the 250-year Wedgwood history, it is one of the most unique industrial archives in the world. The importance of the collection is explained in more detail in this Wedgwood video link.

The collection is under threat because a legal loophole allowed a Wedgwood previously in liquidation to place pension debt in the Museum trust. The trustees have no option but to try to pay off this debt by selling some or all of the collection.

We cannot lose this collection from the UK or allow it to be dispersed around the world to private collectors. It is OUR heritage and I urge you to donate to help meet the £2.74m shortfall still required to keep the collection together in the UK.

Thank you for your support.

How to Choose Your Pottery Clay Body

What is clay?

Flat plates of clay particles

Before choosing your pottery clay body it is first important to understand a little about clay and why it is used as a component of a clay body. Clay is a mineral extracted from the ground which can be readily moulded like plasticine. At microscopic level, the particles of clay have a flat plate-like structure giving them this plastic like property. The 2 most commonly used pottery clays are Ball Clay and China Clay (Kaolin). Ball clay tends to be very plastic-mouldable but off white in colour. China clay is less plastic but has a whiter fired colour. Many other clays are available but they tend to be off white to red in colour and therefore less used in high volume white pottery manufacture.

What is a clay body?

The terms clay and body are used by potters almost interchangeably. However in most cases it is not technically correct! In simple terms a body is a formula containing clay and other minerals. Therefore clay is a raw material component of a body. In past times a body was simply a clay dug from the ground which was variable in both its composition and properties. However, modern commercial potters no longer rely on bodies manufactured from clay alone. To achieve specific properties they are scientifically formulated in a very precise way. A wide range of raw clays and minerals are used from all around the world. They vary in colour, strength, particle size as well as mineralogy and purity. No two clays from different parts of the world are precisely the same although for comparison purposes they can act in a similar way when used as part of a body formula. For studio pottery manufacture coarse minerals called grogs are often added to the clay body formulas to give additional texture appeal and improved properties.

How to choose the best clay for you

Firing range of your kiln

The maximum firing temperature of your kiln should be your first consideration when deciding which type of clay body to buy. It is no use choosing a stoneware clay firing 1250 C if your kiln will only fire to 1200 C. Lower temperature kilns are suitable for earthenware and terracotta bodies (less than 1200 C) whereas high temperature kilns are acceptable for most bodies including porcelain and stoneware.

Colour

The fired colour of the body will often dictate the cost. In general whiter clay bodies are more expensive than buff or cream coloured ones. The type of clay body you use is often prescribed by your colour selection. For example porcelain and bone china are always very white after firing.  To give you an idea of the fired colour produced by the different clay body types see the section entitled 'range of bodies'. Please also note that the firing temperature has a significant affect on the fired colour!

The making Process

The making process you intend to use to shape the body is also an important factor when considering the most appropriate clay body. Clay body sub-types allow you to select a clay suitable for all major forming operations including throwing, hand-building, sculpting, casting or machine making.

Size of your work and end use

The size of the pottery piece you plan to make is also important. Larger pieces often require a more heavily grogged (less plastic) clay whereas smaller pieces of work can require more plasticity. In addition, the end use of the ware, whether it is purely ornamental, for outside use, or designed as functional tableware will affect your choice of clay body.

Texture

For the more experienced potter the texture of the clay body after firing is often important.. The feel, look and strength of the ceramic piece is strongly affected by this sub-type of clay. For example the grogged subgroup of bodies generally add texture, strength and stability, whilst an ungrogged body will result in a smoother more polished finish.

Glaze compatibility

Whichever clay body you choose it is imperative that you select a glaze which is compatible with the body. This technical compatibility is critical to producing an intact piece without faults after firing. Be guided by your supplier who can supply compatible glazes for most body types and firing schedules. For peace of mind you should always test a sample of the glaze and clay body in your own kiln prior to any major production. The temperature and firing schedule of your kiln will influence whether your clay body and glaze are compatible after firing.

Range of Clay Bodies

The are numerous clay bodies produced commercially around the world available to the craft potter, studio potter and commercial pottery. Indeed there are so many that it is impossible to detail them all here. Bodies are often developed to make them suitable for the making process. Therefore suppliers often state  subtypes which define which clay bodies are more suitable for hand throwing, casting, hand building etc.

Clay bodies however can be classified into a relatively small number of categories according to their colour, firing range and texture. Below are a few major examples showing the fired colour of individual body types.

Porcelain

Bone China

Earthenware

Stoneware

Terracotta

Bone China

Bone China

This is a smooth textured extremely white firing body that is also translucent. It is unique in that it contains a high proportion of calcined bone ash . Biscuit firing at approx 1220 C gives it a high strength making it suitable for producing delicate highly decorative items as well as tableware. This type of ware after glazing is often decorated with onglaze colours or precious metal decoration to create stunning pieces of pottery. Electric firing kilns usually produce the best bone china quality.

Porcelain

This is a smooth textured translucent extra white firing body similar to bone china. However two types of porcelain are made, a 'hard porcelain' which requires a glaze firing in excess of 1400 C and a 'soft porcelain' which requires a glaze firing to approx 1250 C. Biscuit firing however is often around 1000 C which allows pieces to be glazed more successfully. High temperature gas kilns are often used to fire this type of body. Porcelain, like bone china, can also be decorated with onglaze enamels and precious metal to create delicate highly attractive giftware as well as tableware.

Stoneware

Stoneware

This class of clay body is commonly used by craft and studio potters. It has a relatively high biscuit firing temperature in excess of 1150C.  Many commercial bodies, available in a range of off white to buff colours, are fired in the range 1250-1300C to give maximum strength. By glazing with a reactive type coloured glaze a wide variety of effects and colours can be achieved. Because of this stoneware has found high popularity with craft potters looking to create unique coloured or or textured hand made pottery. This body type can be used to produce both decorative and functional pieces such as tableware.

Terracotta

Terracotta

This class of body is typified by its unique red terracotta colour. This clay body has a high iron content in its mineral components giving the unique red colour. Like stoneware the smooth texture can be modified, by addition of grog (coarse material), to give a much rougher finish. Terracotta bodies have a relatively low firing temperature of 1000-1050C and are therefore porous and have relatively low strength after firing. Commonly unglazed it is often used for sculptures, planters, tiles and garden ware where the technical properties are not so demanding. For more demanding environments such as tableware the body is often glazed to give a stronger more durable product.

Earthenware

This type of body is often used for hand painting by hobbyists.

For craft pottery this body is biscuit fired to approx 1000 C to allow easy brushing of underglaze colours or coloured glaze on to the porous surface. Following  glaze firing to 1050 C to 1150 C the body colour and underglaze colours show through the transparent glaze producing highly decorative ware.  After glaze firing the body remains porous with reduced strength compared to fully vitrified bodies like porcelain or bone china.

Body colour ranges from white to buff and some bodies are also grogged to provide texture.

For commercial tableware optimum body strength is achieved by firing the biscuit in the range 1180-1220 C but this peak is not often needed for lower strength or decorative only ware.

Special bodies

This range of bodies include, highly coloured bodies, low firing bodies, Raku bodies, and special highly textured bodies. In the case of Raku the body is modified to allow rapid heating and cooling without  cracking, usually by the addition of grog. Making raku pottery successfully requires more expertise than other pottery types and often depends on a trial and error approach. To learn more about Raku read my separate article on Raku making.

Summary

Clearly, choosing the right clay body for you poses a number of technical questions. It is more difficult than is immediately obvious. However I recommend you talk to your clay body suppliers in the first instance and not just search the internet. Their vast knowledge of their products will make the whole process of selection of suitable body and glaze just that much easier.

Good Luck
Happy potting!
The Potters Friend

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend.

Go now to sign up for my free newsletter.

Digital printing of ceramics

Digital printing of ceramics and decals

Digital printing of decals and ceramic tiles is already well established. Computer generated images can be printed directly onto ceramic tiles via special inkjet systems. Alternatively a photocopier type system can be used to print onto decal paper. Of course both these systems require special machines and ceramic inks or toners to produce optimum results. Nevertheless these systems are causing a revolution in the ceramic tile industry.

The detail of decal printing

Ricoh desktop ceramic printer

In the case of digital decal, you can either create a drawing or photograph and then convert it to a digital image suitable for printing on to decal paper. The image is produced as a decal by a photocopier type machine. After printing the image is sealed to the paper with a covercoat and allowed to dry. The decal can then be applied in the same way as conventional decals by a water slide method. Decorators have the choice of either outsourcing decals (small quantities) or for large quantities buying a machine and toners and printing themselves..

The detail of ink jet printing of tiles

Pigment	System	Temperature	Colour
Yellow	Zr-Si- Pr	1250 °C
Red Magenta	Zr-Cd-Si-Se	1250 °C
Cyan	Zr-V-Si	1250 °C
Black	Fe-Cr-Co-Ni	1250 °C
Primary 4 colours used in ink jet printing

In the case of ink jet printing, the digital image is converted to a ceramic image using a specially adapted ink jet printer and special inks. The ceramic tile passes beneath the printer head and the ink jet colour nozzles deposit the image on the tile.

Gamma Ink Jet Tile Printer

Typically up to 10 ceramic colours are used to produce high quality digital images, 4 similar to the primary colours shown above plus additional spot colours. Browns, coral reds and white are commonly used to fill gaps in the colour space. Special printer heads are used to cope with the highly abrasive ceramic inks. For maximum definition and colour intensity special glazes are sometimes used as the base for printing the coloured image. The printed item can be fired almost immediately after drying.

3d Printing of Ceramics

I am constantly amazed at the ceramic challenges I see each year. Whilst making pottery and ceramics is an ancient tradition, new industrial processes and products (or the re-introduction of many older techniques) continue to stretch the imagination.

3d printed sugar bowl

Both in the UK and USA, 3 dimensional digital printing is one such technique. Developed initially for rapid prototyping of plastic objects it is now being used for small special ceramic parts. The potential to build up a ceramic mug  layer by layer  from a computer image is certainly feasible.
 I have seen the initial prototypes which have been glazed and fired. Many technical challenges remain for this process to be viable commercially but I have no doubt that in the long term this will happen.
For more information about this technique see the link project below:-
 University of Bristol project

3d printing using liquid clay syringe

3d extruder printing

This type of printing is also in the early stages of development for ceramics. Many questions remain particularly control of rheology and removing air pockets and machine development.. However the picture on the right shows how the process works. An air powered syringe forces liquid clay out of the nozzle to build up the object in layers. The head could be computer controlled to map out a digital design.
Potentially the ceramic designer can be creative in designing complex forms as well as simple shapes.
Picture and link to more information kindly provided by Ceramic 3D Extruder (FabLabZuidLimburg) / CC BY-NC 3.0

So what does this mean to the hobby or studio potter?

The opportunity to make low cost efficient designs which can be personalised to meet your customer needs. Digital ceramic decals are already established and widely available. But keep following the progress of 3d printing as the potential is endless. Perhaps now is the time to look at ways these techniques can expand your opportunities?

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Art Deco Ceramics

A time of great design or merely time for a change?

Art Deco ceramics are commonly associated with specific designers such as Clarice Cliffe, Susie Cooper and Charlotte Rhead whose striking designs changed the face of modern pottery. However the term covers a much wider range of pottery styles as well as architecture and fashion. But was it truly a time of great design or merely time for a change? Let us examine the evidence.....

The history of Art Deco

Ravel conical ware by Clarice Cliffe
Photo by Leonard Griffin

Art Deco is said to have begun in France in the 1920s and developed internationally especially in Europe and America until the late 1930's. However it was not until the revival in the 1960s that the term 'Art Deco' was introduced. Until that time it was called 'Arte Moderne' or 'Arte Decoritif'. Since that time many modern potteries have developed patterns based around similar principles.
The advent of Art Deco changed the face of pottery in the UK at the time. The bright colours and geometric shapes of Clarice Cliffe especially, was a long way removed from many of the chinese inspired pottery designs that had gone before. However many shapes and designs were influenced by Mexican and Egyptian styles. A revolution in design was in the making! In the UK the popularity was aided by young new designers and and the advent of advertising and to a degree mechanisation. Designer labels grew as a marketing trend and women designers had phenomenal success. It became a necessity for small potteries to find new designs to beat off the threat of imports from Germany and Czechslovakia and Japan.

Clarice Cliffe

Original Bizarre on Athens Shape
Original Picture by Harvey

Clarice Cliffe, probably the name most associated with Art Deco style, was born in Tunstall, Stoke on Trent in 1899. She joined Royal Staffordshire Pottery aged just 17 and briefly studied art at the Royal College of Art in London. Her skill was such that she rapidly became a top designer of ceramics and was probably the first to design both the shape and decoration of UK commercial tableware. Cliffe produced some of the most exciting designs of the times ware adorned with bright colours such as Original Bizarre.

Crocus pattern
Photograph by  Andy Titcomb

Her success resulted in numerous designs being release in commercial volumes between 1927 and 1939. However it was the more conservative 'Crocus' pattern which was regarded as her signature pattern.
Pieces of Clarice Cliffe are now highly collectable and include such striking designs as the conical ginger sifters. Collecting is made easier by the fact that virtually all Clarice Cliffe pieces are clearly marked with her name using a rubber backstamp or litho.

Susie Cooper

Kestrel pattern
From National Museum Wales

Born in 1902 in Stoke on Trent, she entered the pottery industry at A.E. Gray & Co in 1922 and trained under Gordon Forsyth. Brightly coloured abstract geometrics and cubist patterns were her trademark and she developed some stunning designs such as Kestrel and the cube shape galaxy pattern. By 1929 she had left Gray and started her own pottery painting business and this initiated a long and distinguished design career spanning 60 years. Her designs were highly practical with 'fitness for purpose'being a common theme. A black triangular back-stamp with the words Susie Cooper Productions was used until about 1932. After this time a variety of signatures was used.

Charlotte Read

Tube lined plate by Charlotte Rhead
Photo by Chris Bertram.

Born in 1885 into an artistic family in the potteries town of Burslem, Charlotte Rhead studied art at Fenton School of Art. Working for a local company Wardle and Co she learned the skill of tube lining. It was this skill and the influence of her time at Wood and Sons which set her career apart as a designer. Later in 1926 working for Burgess and Leigh she mainly produced ornamental or luxury pieces using her tube lining skill.

Other Art Deco ware

Shelley Vogue shape cup and saucer, designed by Eric Slater 1930

Harmony Art Ware ginger jar - Eric Slater 1932

The Shelley Family was a highly acclaimed producer of Art bone china in the art deco style. Apart from the elegant 'vogue shape' it produced highly decorative vases such as
'Harmony Artware'. Eric Slater was the designer responsible for many of the hugely successful designs.

The Wedgwood family also produced a range of ware in art Deco style. Using a range of designers such as Keith Murray, Skeaping, Makeig-Jones, and Ravilous they continued to create outstanding designs throughout the 1930's. Makeig-Jones in particular changed the image of Wedgwood ware with her inspirational 'Fairyland Lustre' range of patterns.

The Modern Era

Wedgwood Jasper Conran

Clearly many of the Art Deco designs of early period have inspired post year 2000 patterns. Classic, timeless and elegant, almost all top pottery brands have some element of Art Deco in their range. Wedgwood, Portmeirion, Dudson and Steelite each include high coloured decorative patterns or striking geometric shapes. This is not by accident and I can only conclude that the Art Deco period was truly a time of great design!

I would love to hear your comments?

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How to Buy Your Ceramic Dinnerware

Fashion is a strong reason to buy

For the discerning shopper selection of dinnerware is primarily based around fashion. In today's fast moving world, where casual dining has become the norm, our dinnerware often reflects our taste in food or the environment in which we use it. For example Mexican food might well be served in brightly coloured dishes decorated with peppers, spices and other vegetables reflecting the type of food we might eat..However the technical issues are a lot harder to assess and should also be valued highly!

What is ceramic dinnerware?

The word ceramic was derived from the greek word 'Keramos' meaning 'earthen vessel'. The word has now been applied to a wide range of products from terracotta to the finest bone china. Dinnerware and tableware are just two of the categories often used by stores to describe the end use of this range of ceramics.

What type of ceramic is it?

Many types of ceramic are on display in shops and stores. These include terracotta, earthenware, stoneware, porcelain and bone china.

Often it just says china on the box but this means nothing as it is just another broad term implying it is a ceramic! But we already know that!

So just how do we identify the different types of pottery?

One way is to look at the colour of the body under the shiny glaze. The best place to do this is under the foot of the item as this is often unglazed. In order of pure whiteness the following is a generalised guide to the colour.

Terracotta bright red to red brown body colour

Stoneware pale brown to buff colour

Earthenware ivory to off white

Porcelain off white to blue white

Bone China creamy pure white

Bone China and Porcelain

Porcelain and bone china can be more easily differentiated from the rest by their translucency. This means that they they let light transmit through the piece. If you hold a delicate piece of bone china or porcelain up to the light, and wave your hand between the plate and the light, you can see a shadow of your hand through the piece

The technical stuff

What does it all mean?
Once you know the type of ceramic you have some idea of the technical properties. Firstly it is a guide to the strength of the piece and means resistance to chipping,cracking and breakage. Secondly it is a guide to the cost. High quality bone china and porcelain manufacturers use highly refined materials and processes to 'design in' the whiteness,translucency and strength required by consumers. Consequently the cost is higher. However because of the inherent strength you might expect this type of pottery to last longer in use!

As in life things are never quite so simple. The manufacturers of other types of dinnerware (terracotta, stoneware,and earthenware) compensate for their lack of inherent strength by making chunkier pieces. All types of ware can be highly decorated with colour so this is not the differentiator.

So the shopper has a choice of chunkier less white designs or whiter more delicate designs!

What about dishwashing?

The chemical resistance to acids and washing detergents is also worth considering. Generally higher fired glazed tableware such as porcelain and stoneware have a higher intrinsic chemical durability and are 'unleaded' but this is not always the case.
Top brands now indicate their testing to BS or FDA standards and indicate their quality by labelling with 'dishwasher safe' and 'unleaded' or 'lead-free'. The Kite mark is also used as a sign of quality manufacture in the UK manufacture. The astute shopper therefore needs to look for these labels in determining value for money.

Fashion and technical performance are both important
In summary,shopping for dinnerware can be an enjoyable experience! Armed with a little technical knowledge it can be so much easier! Give at least equal weighting to to the technical performance as to the fashionable design in choosing your ceramic tableware.

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

How to Remove Tea and coffee stains from your Ceramic Mugs

It is a common occurrence for mugs used everyday to become badly stained by tea or coffee. The brown stains are unsightly and difficult to remove. Sometimes they become so bad that scrubbing in soapy water does not remove them. Clearly coffee and tea are strong staining agents!

"But what causes the staining?"
It is a combination of hard water, chemicals called tannins, and microscopically rough glaze surfaces. These conditions allow the stains to strongly adhere to the glaze surface. The staining is usually worse in the base of the mug or where there is a sharp corner to hold on to the stain.

"So how do I clean stained mugs?"
Various cleaning methods have been tried and tested including vinegar, bleach, baking soda and washing soda. All have been proven to be successful and are widely used. However Bar Keepers Friend and tooth cleaning powders are less likely to give long lasting damage to the glaze surface. Cleaning with other chemical compounds and scourers whilst successful can create damage to the glaze surface which will make them more susceptible to future staining. So please take special care with your best china or dinnerware and treat them gently for their long term protection.

"So how do I stop staining?"
Manufacturers of the top brands of dinnerware and mugs design their products to resist staining and damage in use. In essence this is done by ensuring the glaze is chemically and physically durable. However,with the widespread manufacture of mugs in many parts of the globe including Asia, it is not easy to know the source and quality of the ceramic mugs we buy.It is almost impossible to assess how resistant mugs will be to staining by visual inspection. Smooth glaze surfaces with few corners will reduce the potential for the stain to adhere strongly to the surface. However, over time the glaze surface may be attacked by dish-washing agents. leading to the dreaded staining.Cleaning the pottery soon after use with warm soapy water will certainly reduce the possibility of staining.

"Summary"

To reduce tea and coffee staining of your mugs, clean them as soon as possible after use in warm soapy water. Use quality mugs from top brands as they will have designed the mugs to be chemically and physically durable. Avoid harsh detergents for cleaning as this can damage the glaze surface and lead to greater staining. Bar Keepers Friend and tooth cleaning powders are preferred cleaners and less likely to create long term damage. If all else fails buy new quality mugs but recycle the old ones. Pottery is a truly 100% recyclable product!

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend. Go now to sign up for my free newsletter.

Is Your Pottery Microwave Safe?

Microwave ovens are now a common feature in most kitchens. Their use both to heat and cook food means a wide range of ceramics is being used in microwave ovens. However the question remains….Is all pottery microwave safe?

Technically this question is a little more complex than it appears. There are general rules such as:-
“do not use ceramics decorated with gold, silver or precious metal in microwave ovens”

 Indeed ceramic with any metal should not be used in a microwave oven. However additional rules depend on recognising which type of ceramic is being used. For the consumer this is not an easy task.

All ceramics are not the same!

Ceramics are now made all over the world and it is not always easy to establish their source or quality or type. However ceramics that have been fired to a high temperature and are non porous are generally considered to be acceptable for use in microwave ovens. These ceramics include stoneware, porcelain, bone china, and vitreous cookware. Other ceramics which have not been fired to a high temperature have to be used with caution. For these type of product to be used safely there is a need to ensure that they are both dry and have not absorbed water. This can happen in many circumstances particularly during washing or in storage in the fridge. These products need extensive safety instructions to be used safely.

Top brands help the consumer by labelling their products as ‘microwave safe’. Less well known products cannot give this assurance and often do not label at all. So buyer beware and if in doubt do not use in a microwave. Look out for BS or CE standards as a sign of meeting a quality standard.

In summary, most high fired ceramics are suitable for microwave oven use. Lookout for the labelling used by branded products to give reassurance on acceptability for microwave oven use. If in doubt “keep out” is a good motto to remember!

Why not test your pottery knowledge with my quick pottery quiz

More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend

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How to avoid scratching your dinnerware

So why does it scratch?

A scratch on a plate at high magnification

Pottery is hard and strong! If you don't believe me try cutting it with the sharpest steel knife you have. Whilst it may mark it will not break. Steels used in everyday cutlery are softer than pottery glaze!

To scratch a pottery glaze you need a material of similar or greater hardness. So pottery can scratch itself. Glaze on glaze contact will cause surface damage and when there is excessive or repeated damage the eye sees it as a scratch!

So a scratch isn't a scratch until you can see it!
Glazed pottery is susceptible to surface damage as soon as it comes out of the production kiln. During the manufacturing process care is taken to avoid excessive damage by careful handling of the pieces, the use of protective sleeves and optimum packaging for transport.

However in our homes damage to our pottery happens all the time. For example each time we use a plate it is damaged by contact with other pottery. Creating a plate stack to clear the table, placing plates on each other in the sink, washing them in detergent, sliding them into clean stacks all contribute to damage. Clearly there is a cumulative effect of this damage which results in the appearance of scratching.

So how can scratching be avoided?

Taking care to handle the ware gently, in a similar way to the manufacturer, will extend the life of the pottery. Using protective sleeves and avoiding sliding contact are particularly important. In addition the ware can be adversely affected by detergents and strong acids so prolonged contact with these chemicals should be avoided.

Whilst these precautions may seem fanciful and few people will take the time or effort to follow them, they do work!

Alternatively, if all this is too much then there is one other thing you can do......buy pottery that has a glaze that is not highly glossy and has a less than mirror like finish! Whilst this does not reduce the damage, scratches normally visible to the naked eye are less apparent, and the ware appears less scratched.

Alternatively why not test your pottery knowledge with my quick pottery quiz

More information and other technical articles on pottery and ceramics can be found at my website www.pottersfriend.co.uk

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Ten pottery making tips for the beginner

My top 10 pottery making tips for the beginner

1. Go to pottery making classes. Everyone has to learn somehow. Although it can be comforting to learn on your own it will be much more fun with others. In addition your skills will improve much quicker!

2. Don't be put off by the terminology! Pottery making uses some strange and quirky terms. But dont be put off! It wont be long before you know green ware from biscuit ware.

3. Be prepared to get dirty-you can tell a potter by his hands and shoes!Even with an apron it is impossible to stay clean when making pottery. Your hands and shoes will get dirty! Treat it as part of the fun so dress appropriately.

4. Enjoy the experience-dont be put off if it goes wrong!It goes wrong for everyone including the experts so don't be afraid to experiment. Remember that your designs are unique and you have the chance to express your own creativity.

5. Read some simple pottery making books. Lots of pottery books are available so choose books with simple descriptions and pictures to get you started. My recommendations can be found at www.pottersfriend.co.uk/books/list_books.php Books,however, are no substitute for classes but they should reinforce your learning.

6. Ask questions. Asking questions aids memory so you learn quicker. Don't be embarassed to ask even the most simple of questions. Remember you are probably only saying what many others are thinking!

7. Practise then practise some more!This probably should be my number 1 tip on the list. As with most things in life, the more you practise the more skilled you become and the more enjoyable will be the experience.

8. Develop your own style. Dont be afraid to experiment-its your chance to show your artistic flair.

9. Make some pots & give them away. It makes you feel good and you might even find a soul mate.

10. Share your experience with a loved one. Making pottery can become a real passion so dont forget to share your experiences with your loved one. They might even want to join you at the next pottery class.

For the more experienced potter why not visit my tips page at www.pottersfriend.co.uk/tips.php

Alternatively why not test your pottery knowledge with my quick pottery quiz www.squidoo.com/potteryquiz

Making pottery-simply art or sophisticated science?

As I was watching an experienced potter throw beautiful shapes recently it made me reflect 'how incredibly simple it seems in the hands of a true expert'! Starting from a lump of clay, shaping it into an interesting form, drying, finishing, glazing, and firing can take up to 2 weeks. A labour of love to create that special unique piece! But those who have tried to make pottery know that these are mere headings for skill, artistic flair,experience and a good deal of knowledge and science.

Incredibly, in the pottery industry where 'lean manufacturing' is all the rage they attempt to produce finished ware in a matter of hours! They breakdown every operation down to its most basic level (steps). Each step in the process is identified and the skill, tools, material, manpower and time required. By defining the process in this way it is possible to identify the number of steps and value of each step in an operation. Lean manufacturing philosophy requires the removal of waste in all its forms. Waste doesn't mean just waste material, but wasted human movement, wasted product movement, overprocessing, excess stock, not right first time, or wasted waiting time.

Often the target is to improve efficiency and the first step is to remove as many non value added steps as possible. An example of this might be to remove the clay ware from the sponge/fettling stage immediately to the biscuit kiln instead of to an intermediate storage area. Often by looking at operations in this way new or more robust ways of processing are identified and introduced.

"So what" I hear the true potter say-this means nothing to me. And he is right in some ways! It is often by trial and error that his artistic flair can flourish. A missed out glaze ingredient creates that wonderful new glaze colour or the kiln underfires showing unusual but unique glaze effects!

However he is also wrong in some ways. He has already adopted some of the lean principles without knowing it! Often the potters studio is laid out so all his tools, materials equipment are close at hand (thereby reducing waste movement). He recycles the clay and glaze (reduces waste materials) and tries to make a number of items at a time not just one (reduces waste time).

I believe that both the studio potter and industrial potter can learn from each other. The studio potter can learn to reduce waste allowing him the time to be more creative and the industrial potter can learn to be more creative in design allowing him to sell more product.

Surely making pottery is both a simple art and a sophisticated science! What do you think? I'd welcome your comments.

Pottery and ceramics find so many uses in our homes!

In these days of credit crunch blues, recent events have made it clear to me that the pottery making in the UK is still alive and well and doing fine. Unique designs and small scale production and customer service seem to be order of the day as the larger producers have been hit hardest by the downturn in the hotel and gift markets.

The term 'Pottery' is uniquely used by the general public to describe anything ceramic and we should not underestimate the impact these forms of ceramic have in our daily lives. Ceramics are evident in our homes in so many areas. Drink tea made with water purified with a ceramic filter in a bone china cup. Cook your evening meal on your ceramic cooker hob. Keep warm by sitting by your gasfire with its insulating ceramic bricks, and ceramic logs or pebbles. Take a shower in your bathroom lined with decorative ceramic wall and floor tiles, and your bespoke table top washbasin. Relax and read a book under the light from a sculpted ceramic lamp. You might even want to watch your TV with its many ceramic parts!

Even outside, ceramic pots of all shapes and sizes as well as other unique ceramic animals, toadstools, fairies, wind chimes, sun dials, coloured glass gravel and BBQ chimneys add individuality to our gardens.

Clearly many of these items are still made in the UK and provide employment and job satisfaction for many.

It is comforting to know that virtually all of these items are reusable in some way and should not find their way back to landfill sites. Keep selling the message 'ceramic is green' ! (Avid potters -sorry for the pun!)

I often wonder what the most unusual or surprising use for ceramic there is out there?

Please let me know if you find something interesting! For more ceramic information visit the Potters Friend's website www.pottersfriend.co.uk

Pottery Clinic

Glaze blister at high magnification

Post your questions about any pottery or ceramic matter.

All questions are welcome regardless of how simplistic they may appear !

My commitment is to respond in a timely fashion and to provide the best advice that I am able to based on my own perspective and the information provided.

I look forward to answering your questions