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Sean K

Oil to mix with cobalt oxide and fire over glaze at 800 deg C.

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Howdy Folks, I'm new to this whole business of working with clay... but I've been a sculptor in metal, and painter, for 20 odd years.

 

I've been looking for techniques to do what I want on the clay and one that appeals is the old Euro style blue on white were the piece is glazed white at medium or high fire and then the blue is put on by printing. I found a book at the library the showed the process of engraving copper and then printing with cobalt oxide, mixed with an oil, onto soaped tissue paper which was then cut up and pushed onto the glazed surface and fired to about 800 deg C.

 

I like this technique and would like to use screens to get the 'ink' onto the tissue but I'm unsure of what oil to use as a carrier and whether anything else is added to the ink. I suppose it would also need a binder of sorts... maybe silica and a flux to get it melting at 800.

 

People have kind of scoffed at me and suggest using craft style 'china paints' as if the technique is too low brow for serious pottery, which I find silly as it's a traditional technique and shouldn't be any less valid than other ways of putting patterns on clay. I could go out and buy stuff but I prefer knowing what's going into a mix.

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There is nothing low brow about China Paints. That is exactly the temperature range you are talking about. I am not familiar with the exact oil but it comes with China paints I had a lot of pigment files donated to the ceramics program when I was teaching. I never got involved with it then. But look into China painting info. Paul Lewing had written and excellent book on China Paints published by ACERS.

He also presented a session in Seattle at the last NCECA. China Paints are very "cutting edge" in Ceramic Arts.

 

I did a research paper in college on making lusters and the complex recipe called for a varnish or lacquer plus oil. You should be able to look it up with a little research. You might even find it under "Paul Lewing" and ceramic Arts Daily if he has done something there.

 

Marcia

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Thanks for your reply Marcia,

You've given me some interesting things to look into. Also interesting how you mentioned cutting edge as all I'm looking at doing is finding techniques to use with my clay stuff that are simple and tell the story I want to tell. I've only been into clay for a few months now and I find it entirely disturbing how there is a tendency, I'm at school doing this, to emphasis the technical and intellectual with clay and glazes, when to me the fundamental ability to work with the materials imaginatively is almost unperceived as important at all.

 

It's almost as if this cutting edge, as it were, is a possible revolution in pottery which is seeing people just wanting techniques that'll work efficiently as opposed to being masters of an esoteric art.

 

Yeah, I haven't really looked at lustres but maybe they have the same qualities involved.

 

Cheers, Sean.

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I've only been into clay for a few months now and I find it entirely disturbing how there is a tendency, I'm at school doing this, to emphasis the technical and intellectual with clay and glazes, when to me the fundamental ability to work with the materials imaginatively is almost unperceived as important at all.

 

It's almost as if this cutting edge, as it were, is a possible revolution in pottery which is seeing people just wanting techniques that'll work efficiently as opposed to being masters of an esoteric art.

 

 

 

Hello Sean

Welcome to the challenging and perplexing world of ceramics. Fortunately or unfortunately, depending on your mindset, ceramics has not yet reached the stage where instant success can be achieved without prior learning and understanding the complex interactions of the materials that are used along with the complexities of the firing process. Ceramics is an art form using a wide range of skills. Without the knowledge of this craft one is not in control of the results. I am not setting this out as a judgement on your thoughts but rather to help you understand the complexities behind the question you initially posed.

 

1. The "old Euro style blue on white" commonly known as delft, faience, majolica used cobalt mixed with water and a small %age of flux painted on the UNFIRED glaze surface. The work was then fired to the maturation temperature of the glaze. Today the majority of blue and white ware in this style is achieved by the use of screen printed overglaze decals.

 

2. When copper plate printing techniques came into being prints were made in the manner you described but were only used on BISQUED surfaces as the porosity of the ware was needed to allow the oil to be absorbed into the surface so that the tissue could be removed cleanly without smudging. This is not able to be done on glazed ware. I have attached a PDF I made from Ceramic colours and Pottery Decoration by Kenneth Shaw. This book is the standard for understanding overglaze. This excerpt fully explains the copper plate process as well as all the problems encountered with its use.

 

3. As you are aware certain oxides are used to obtain colour in ceramics. It is how these oxides are prepared that allows their use throughout the whole ceramic spectrum. China paints are simply ceramic colour mixed with flux to allow the colour to "melt" onto the fired glaze surface. The proportions of flux to oxide varies according to the requirements of each individual oxide. These compounds are then fritted (heated to melting point and then crash cooled) and then ball milled to the fineness required for use as overglaze. Basically ceramic overglaze colour is nothing more than an extremely low firing glaze applied to a non absorbant surface. This has been well and truly worked out by the ceramics industry which needed consistency of results for their production. The colours (china paints) are then mixed with either oils or water based mediums for use over the fired glaze.

 

4. The overglaze answer to underglaze tissue transfers are waterslide decals. These can either be screen printed or digitally printed onto decal paper which is really a portable version of the early "bat prints" which used gelatine bats to transfer the colour. With decals the gelatine base is on the paper. You can make your own ceramic overglaze decals using china paints and a medium (oil or water based) and a silk screen or you can print out laser decals using a laser printer. There is heaps of info here in the forum on laser decals.

 

5. The question of which oil to use depends on the properties you need. There is a wide variety. Following Marcia's suggestion of Paul Lewing's book is a starting point.

 

6. Tissue transfers are readily available today as they are coming in from China and Japan. The factories I visited in China used engraved zinc plates and used a water based mixture not oil.

 

7. Overglaze decorating is simply part of the whole ceramic continuum. It has been in use since 1000 AD. Somehow it has been sidelined with the emergence of STUDIO ceramics last century. However today there is a growing awareness with potters embracing this within their oeuvre rather than simply thinking of it as the China /Porcelain painters domain. An increasing number of china painters are turning to pottery techniques to more fully understand the processes involved.

 

Regards

Johanna

Copper Plate Printing.pdf

Copper Plate Printing.pdf

Galla likes this

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Hi, Sean,

 

 

 

I am also new to ceramics, an infant of just three months. I have been handbuilding small items with low fire white clay. I also love the look of the blue and white china. Although I preferr the patterns from China that are hand painted. I only use premade glazes and underglazes which I paint on by hand. I have had good results so far but am striving for a more auteintic chinese brush look. I may have to go to a handmade glaze for this. The problem I see with the china paints is that they require multiple firings. I also could not find a difinitive answer to the kind of oil used. Good luck in your endeavers.

 

 

Johanna, thanks for all the info.

 

Chantay

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