grog and coloured clays

kengai

Hi
What type of grog do You use-how many(, "grain"?


and...

What kind of oxide do You prefer for dye(ing) light clays iron ox. might increase shrink clay? maybe manganese ox... What do YOU think about this?
I love Your brown, grey clays


Thank You - Martin

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Nomatch1

Iron oxide can cause the clay to act differently especially in a reduction firing. Manganese is a toxic substance and should be used with care. In it's powder form it can be inhaled and as most commonly done, absorbed through the skin. There have been several well known potters that have died from it's use by rubbing it into their clay bodies. If it is in the clay, it could go in through your skin and poison you.
Do some research before you use it, carefully.

Boondock

I have to preface the following with "I'm new to pottery" but I'm spending alot of time researching oxide washes.


colored clay---Oxide washes are alot easier as a surface treatment than changing the actual color of the clay. Iron Oxide, which includes BIO (black iron oxide), RIO (red iron oxide), burnt umber, ochre, crocus martis.

Nomatch brought up toxicity in some of the raw materials, and I got the same speech from the pottery supply store, and the professional potter I'm working with. Bottom line... Buy and use a GOOD respirator/mask when mixing oxide washes and glazes. Maganese is a serious inhalation hazard.

The other option is to use a light clay, and apply a commercial stain. Stains are a mix of oxides and other stuff (fluxes, etc) that are consistant in color. The downside to stains, is that they are expensive, and very smooth in the color palete. Oxide washes made from raw materials can produce a more varied/speckled/mottled color. The company "Mason" is the most well known.