Flash Luster & Kosai Glazes
I began my interest in Luster glazes after doing a Kosai workshop with Eduardo Lazo in 2009. I needed to develop my own non-leaded golden shiny glaze for porcelain. This quest was my introduction to the alchemy of turning silver into gold. My pottery is unique because of the elusive Flash Luster glazes I have researched and developed. Unlike resin lustres or pigment lustres these elusive glazes were first introduced in the early 1900’s by Zolnay and Massier. . These luminous jewel-like glazes produce subtle mysteries to my forms, providing a highly reflective surface where colour appears changeable. Further testing has led me to a matt variation that reminds me of the prairie sunsets of my childhood.
My porcelain pieces are thrown on the potter’s wheel and dried slowly under plastic. Once bone dry I use the traditional Chinese methods for trimming and after the soft bisque I wet sand with silicon carbide paper to get a soft smooth surface. A liner glaze is put on the inside and on the footrims and high-fired to cone 10. Flash Luster glazes with the nitrates of precious metals (copper. bismuth, and /or silver) are sprayed on the outside of the vitrified porcelain and fired again to cone 03 in an oxidation environment. A thin metallic surface embeds under the glassy matrix and develops further during the fourth firing where a reduction atmosphere is started upon cooling. It is this reduction temperature that controls the colour of the glazes. Further testing has also led me to matt variations with colours similar to raku. Subsequent firings are usually made for effects or fuming with stannous chloride (decorative only). See Kosai & Fuming below.
My work is not only decorative but is functional in the fact that my work will hold water. I am also currently testing these glazes with the intent of creating lustrous dinnerware. My personal mugs and bowls have survived the 6 month dishwasher test with no changes to the colour or surface qualities however handwashing is recommended. My glazes do not contain lead or cadmium. It is the infinite variety of these effects that would keep my work fresh and of interest to the public as well as learning and growing as an artist.
One might ask why I would choose to stay with porcelain when there would be other clays that could be more appropriate for lower temperature glazes. I enjoy the process of working with porcelain. I am accustomed to using the traditional Chinese methods of throwing as well as the tools and process of trimming dry. It is the time of the day when I need to be mindful. I appreciate the blank canvas where glazes come alive. The only deterrent is that some pieces do not ring like a bell after going through multiple firings regardless of all my efforts. Other clays do not give me the tactile qualities I am looking for. It is important that my work is elegant, jewel-like and weightless.
Pricing reflects the costs of the materials and firings as well as being handcrafted. I am confident it is in line with other artists work in the galleries.
As it is important that I have a personal relationship with you, please email me to see my current availability. I try to have these forms in stock ready to glaze and fire in the colour of your choice. I will send you some images for you to decide which you love the best either by email or text.
Pricing is in Canadian Dollars. I am able to ship worldwide, unfortunately this does not qualify for free shipping. I will send you a special gift instead. I’d like to ship using the method you prefer best, Greyhound, courier or regular post. Insured shipping will be approximately 10% of the price of a pot, with a minimum of $20. If you sign up for my newsletter there will be no shipping charges and special prices on my “Pottery of the Month” Club.
I always try to put my best work in the homes of others. I keep my seconds for myself so please do not ask if I have a sale on blemished pieces. If by chance you are not totally happy with the piece you have chosen, I offer a 30-day return policy. If it does not seem as beautiful in person or as you envisioned please return it and I will gladly replace it. I truly want you happy with the pot you have chosen. If you decide that my pottery is not at all what you expected, and you can’t think of a person you could maybe gift it to, then I will most definitely refund your purchase price, less shipping. Thank-you!
Contemporay Vapour Glazing
via Eduardo Lazo
Contemporary vapor glazing firing techniques often yield remarkable visual effects. Vibrant and exciting rainbow-like colors and designs are imprinted on ceramic ware by fuming certain chemicals onto the surfaces of glazes that have a high metallic content and onto which a layer of precious metals has been applied.
The product of this unique process is known as Kosai ware (Japanese term for hue of light). The emerging and stunning colors are likened to Newton’s rings, scientifically described as thin film colored interference fringes due to the reflection of light rays between a spherical and a flat glass surface. On a ceramic glazed and fumed surface, the effect is readily compared to that unique rainbow color pattern seen when water covers an oil spill on asphalt.
Fuming works well with many glazed surfaces. Although a mother of pearl effect can be produced on light or clear glazes, the more dramatic Newton’s rings are better seen on metallic glaze surfaces covered with gold, platinum or bronze. The multi-firing technique I use can involve as many as seven kiln firings.
- The first firing is called bisque (cone 04) and serves to “harden” the raw clay.
- The second firing matures the first glaze application which can range from 1800°F to 2400°F.
- The third firing matures a second glaze application at a lower temperature than the first.
- Sometimes an optional third glaze is applied with a fourth firing.
- The fifth firing serves to fuse the precious metals to the surface.
- The sixth firing constitutes the vapor glazing with selected chemicals (bismuth, barium, strontium, tin or iron). It is application of a thin layer of these metals that causes the interference of light and the separation of the colors of the light spectrum as they reflect off of the glaze surface.
- The seventh firing can be a smoke firing to darken surface cracks that may have developed.
As you can imagine, considerable time and skill is involved in making and successfully firing any given piece of Kosai ware, not to mention the expense of securing refined chemicals, precious metals (i.e., real gold), and glaze materials.
Kosai ware is durable, that is, the brilliance will not fade in time nor when periodically exposed to the sun. Kosai ware can be cleaned with water.