Our Patinas

Mottle was discovered by a friend and fellow metalworker, Martin Metal, when he accidentally misformulated a patina recipe in Hughes and Rowe. It is a burial patina: wood shavings, or bark chips, or (ideally) wood-turners' waste is soaked with a mixture of chemicals. The brass piece is then buried in the wood chips for a few days. About once a day, depending on weather conditions, the mottle is checked to be sure it is adhering over all the surface of the piece, and more liquid is generally poured on to keep it moist. When it is well covered, the piece is removed, and let dry for a while with most of its wood chips still clinging. Then the wood chips are brushed away using a medium-stiff wire brush wheel in very good ventilation, and ideally with a breathing mask. The colors yielded are extremely variable, always containing greens and blacks and blues, usually yellows and browns as well. We exercise only a limited degree of control over the colors which come out.

Either before or after brushing off the excess wood chips from the dried or drying piece, the whole can be heated with a torch, to produce a wide range of colors collectively called Burnt Mottle. Blacks, browns, yellows, greys and pinks appear regularly, and blues and greens are often left in a low-intensity burn. Beyond pink, patches of intense oranges and reds in black and brown fields can be reached on occasions. This patina magnifies the uncertainty of simple mottle, so it is quite unpredictable, and our control over it is quite limited.

A less unpredictable way of darkening and browning the mottled patina is to add a layer of the transparent brown patina on top of plain or very lightly burnt mottle. This is referred to as Brown Mottle, but it is often difficult to tell apart from certain burnt mottles.