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About Over Glazes - A How-too: Article or Project

Suitable glazed fired ceramic item
Chosen over glaze (decal, luster, metallic)
Sponge
Water
Mineral Spirits
Q tip cotton swabs
Paper Towels
Essence

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Instructions

An over glaze is anything that is applied OVER fired glazes to produce special effects. This can include: decals, china paints, gold, silver, and lusters like Mother of Pearl, Halo Gold, Weeping Silver, weeping, gold, etc. One note: Metallics like gold, silver and platinum can be applied to unglazed porcelain bisque because of its lack of porosity; however the effect is considerably different. Decals can also be applied to prepared fired porcelain bisque

In all of the above cases, the over glaze is fired on after application. This is usually a much cooler firing which reaches temperatures just hot enough to mature it and bond it to the glaze. If fired too hot, the over glaze most often will burn off.

China paint is a condensed color pigment designed to go on top of glazed china, glazed earthenware or unglazed porcelain bisque. It comes in several formats. It can be purchased as a powder or as a thick paste. In the case of powder it is important to mix it with a good china mixing oil and take extreme care to make sure it is pressed smooth. Most people prefer the paste as it is premixed and ready to use.

Decals are one of the most popular over glazes. They are painted pictures or graphics that are adhered to a plastic type film in reverse. This film is attached to a special paper backing, sandwiching the paint between the plastic and paper.

Decals can come opaque or semi-transparent, so it is important to know this before applying to your glazed item. If you have a dark background, you will need an opaque decal or it will not show up.

Fired Gold, Platinum, Silver are somewhat tricky to learn. Not difficult, but touchy and temperamental. These precious metals are suspended in a liquid and do not look at all like you would expect. Different brands have a color agent in them to help you see where you paint them. There are different grades, especially with the gold. Some is 14k, 12k, 10k etc. The metallic is released during the firing process.

The resulting sheen will be affected by the sheen of the glaze. Gloss glazes will give a high sheen and Matte glazes with give a satin sheen.

Lusters (Mother of Pearl, Mardi Gras, Halos) are chemically induced special effects that create a touch of elegance to glazed items. These are iridescent over-tints of varying color and degrees of translucency.
Applied unevenly which is its purpose to create the greatest effect. Can be applied to any color of glaze with differing results. No two pieces turn out the same.

Halo Gold and Platinum are applied similarly to MOP; however you need to apply two coats. The second must be applied before the first is dry, so gauge your area to be covered so that you can do that. When you apply your second coat (while still wet), tip your brush into the bottle then tip it randomly over the surface of your piece. It will cause the luster to 'halo' or radiate out into circles of various sizes. It is nice when these halos over-lap somewhat. You can create as many 'halos' as you like. With very large pieces, work in sections so as to not over dry the applications. Allow piece to dry thoroughly before firing.

When EPA and CPA got involved in the field of paint production, many of the wonderful lusters were taken off the market in the USA; however some manufacturers are making great strides in duplicating some of them.

 

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