Enamelling is an old craft known since last centuries before Christ. Enamel is a glass melt fused onto a base made mostly of metal. Firing temperature is between 700 and 900 °C. Enamel has many advantages with hardness (5.5 degrees of the M. scale), luster, steady color and beauty being among those most appreciated. Durability of enamel is superior to other finishes.
Industrial enamel is known from many things of every day use including dishes, stoves, street signs, etc. It is annealed to steel. Stickiness to thoroughly cleaned metal is reached thanks to a layer of fired background enamel. Additional colored enamels are attached to this layer.
Artistic enamel can be met in work of goldsmiths and jewellers. It is attached to noble metals (copper, tomback (red brass), silver, gold), sometimes industrial enamel is used as a background layer. Compared to industrial enamel, it has higher luster and brighter colors in a richer palette.
For a perfect result,Škvorsmalt deals with both types together with grindling.
Small Vocabulary of Enamel
ažůr (plique-á-jou) ) - enamel from which the background layer has been removed resulting in a glass-like surface
bulging - convex surface typical for enamelled tags
champlevé - enamel in troughs and channels made by grooving or molding
cloisonné - enamel in cells created from metal strips or wire
ground - basic enamel ensuring stickiness of additional colored enamels
Limoge enamel - hand-painting with a fine milled enamel
muffle oven - an oven with a heated space separated from heating spirals
opaque - - non-diaphanous coating enamel
transparent enamel - includes enamels from translucent to fully transparent
silk-screen (serograph) - printing with enamel colors over a sieve made usually photographically
enamel transfer - print on paper by enamel color, resulting “sticker” is transferred to a piece being enamelled, then fired
A Little from History
By a test on a heated piece of copper, the types of glass melting evenly were looked for. At the moment they began to melt, selected glasses were thrown into a copper vessel with water to crush by sudden cooling. Then they were further crushed with a hammer and the powder gained was stored in shells. Using a cut feather or a small spoon, enameller filled up the cells to be enamelled with wetted powder of certain color (dry powder would make a porous surface after melting), and covered them completely with big pieces of glowing coal on an iron plate, under an iron lid with openings being narrower outside (to protect enamel against ash). By continuous air supply, temperature was increased until white glow of the iron lid openings. Having waited half an hour, coal was removed and when the openings blackened, enamel was cleaned up, the cells filled with powder again and the whole process repeated; at the first melting, a hollow usually appears in the middle of the enamel area. This is characteristic for the enamel with wire frame where often only one melting step was taken to be satisfactory. Afterwards, surface was smoothed to the level of the cells and polished by various means.
Jan Filip: Artistic Crafts in Prehistory