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The Majolica Earthenware Process

Section: Glazes, Subsection: Low Fire

Description

Understanding the advantages and disadvantages of low fire ware and the chemistry of physics of the glazes and bodies used is a key factor to exploiting this type of ceramics

Article Text

If you are interested in vibrant color, then read on. I am going to try to convince you to try Majolica because it is one of the best ways to achieve ware that is alive with color. On the other hand I also want to make sure you know about the limitations of this process so you are ready to "roll with the punches" rather that get upset when you run into problems that appear much less frequently in stoneware. I will set aside some myths about it and then provide some suggestions on how to go about making this exciting process work for you.

Majolica (or tin glazed earthenware) is a very old pottery process that has long fascinated collectors. The term 'majolica' is Italian (from the port of Majorca), however, the technique was also perfected by the Spanish, French, Dutch, and Slovaks. It is characterized by white-glazed red earthen-ware clay decorated with over-glaze floral and other brush work designs.

Advances in ceramic materials, kilns, and stain technology make it possible or you to produce attractive and exciting majolica-like ware today that is technically superior to any of the classic ware of the past (artistically is another matter!). Although the formidable challenges took hundreds of years to overcome, with a methodical approach now you can have majolica working in weeks! However, do not be overconfident. As you will see, some aspects of earthenware are much more difficult to perfect than with stoneware. Glaze manufacturers in the ceramic hobby market have shielded users from this complexity and we will follow suit and seek the help of the frit and stain industries to get the process working with a minimum of fuss.

Forgive me, however, for not holding true to the traditional materials. In this sense, I use the term 'majolica' loosely. For example, there is no compelling reason to use tin to opacify the glaze and lead flux is no longer needed or even legal. It is reasonable to fire a little higher and longer for better ware strength, and introduce new decoration materials and techniques. In fact, it is not even necessary to use a white glaze with overglaze stains if white and colored slips can be covered with a transparent glaze.

If you have studied or seen majolica ware, you may have dismissed it for a number of reasons. But are they valid? You might say:

Majolica's Advantages

A few things to be aware of:

Getting Started With Your Own Majolica

Repeat the above process until the glaze fits well. You now have a reliable transparent glaze.

Add 12% zircon opacifier (i.e. Zircopax or Superpax) and mix the glaze and try it again on a tile. If the color is not white enough, increase the opacifier to 15% or more, but be careful since zircon increases glaze melt viscosity, and thus, raises the likelihood of crawling and pinholing.

When the desired opacity is achieved, stress test, as above, to reveal possible shivering. This needs to be done because zircon will lower the expansion considerably. If the problem appears, replace part of the frit content with a higher expansion frit and redo the test. Repeat the process until the fit is good. You now have a reliable white glaze.

You now have the over and underglaze colors ready.

Apply the slip in a thick layer to a leather hard tile. Dry the tile. If the slip shrinks and cracks into flakes with curled up edges, remove the bentonite and retest. If it still does it, add kaolin at the expense of ball clay. If the slip flakes and falls off during drying, add ball clay at the expense of kaolin (10% to start).

You now have a working slip base. The final step is to develop some colored slips.

Now you have everything ready and you know it works. You are in control. I suggest you glue all successful glaze and slip samples on boards and hang them up in plain view as inspiration and direction.

To begin production, I recommend you get a 50 lb. bag of frit (about $100) and mix 5-10 gallons of white and transparent glaze. It is always better to dip the ware completely to get an even layer. If you don't have a pair of dipping tongs, be sure to get some.

Armed with the above working materials, spend the rest of your life investigating the infinite number of combinations, colors, and decorative techniques possible. Enjoy.

In Bound Links


By Tony Hansen




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