OXIDES

Hello again from Namibia in Southern Africa,

We are having our usually sunny winter, with cold nights and warm days. I hope you are all enjoying your summer.

 I was asked to talk about oxides this month. I'm sure many of you know even more about them that I do, but I'll share what I know.

 Oxides are the raw materials used in coloring ceramics. They are used by potters in glazes, stains, slips, terra sigilatta, and even sometimes in clay bodies. Oxides can be used as washes over textured greenware or bisque. Which is what I did in the sample of 4 beads pictured below. The most common oxides used, seem to be, iron, copper, chrome, and cobalt.

                                                                      Raw oxides can be interesting, but remember, they are unpredictable, and can change a lot depending on firing temperature, and how they are used. For example, I used copper oxide to antique the face pot below, and as it was over terra sigilatta there was no glaze used. I painted the same wash of copper oxide on the leaf bead above, but in this case it was under a clear glaze. Under this particular glaze, it gave a green/black effect rather than just black. All the beads above were antiqued with an oxide wash as labeled, and then fired with a clear glaze to earthenware temperature.

copper oxide wash over terra sigilatta


If you want consistent predictable results, stick to stains, which have been manufactured to take all the guess work out. However, if you want to experiment and explore, then by all means try using oxides. 

Oxides are fairly inexpensive, and very concentrated. It takes very little oxide in water or decorating medium to make a wash ( 2% to 8 %). They also tend to be harsh in color, so may people tone them down a bit by mixing them. You might try making a clay test board and overlapping different oxides.  Take notes :)

As far as hazards go , the danger in oxides come form inhaling, or ingesting. Use you usual ceramic studio safety guides and you should be fine. Wear a mask when mixing, and don't eat or drink around them.  Wear gloves. The only oxide I have read about, that you should avoid using on food containers is copper oxide, which if used in a soluble glaze can leach out.  Please note however, I am no expert on the subject. If any of you know of other dangers please let us all know.

 iron oxide wash on buff colored clay

bands of texture alternating with glazed, ( blue & cream) and unglazed, with oxide washes .

Although I have used oxides mostly as a way to bringing out texture in clay, you might also consider using oxides with sgraffito, or with various masking techniques. The only limit is your imagination. Have fun playing.

TO learn more about WORK OF OUR HANDS  please visit their blog:
WORK OF OUR HANDS BLOG
Shop their ARTFIRE store here:
WORKOFOURHANDS