HAND-CUT LEAD CRYSTAL
Hand-cutting showcases the art of artisan glassmakers who guide and press lead crystal blanks against carborundum and sandstone wheels to grind grooves and/or facets in cooled lead crystal to create a design.
Water constantly trickles over cutting wheels to prevent them
from becoming hot enough to break the crystal. Without lead
content, the cutting wheels would probably shatter the glass.
Producers of better quality hand-cut lead crystal hand-polish cuts by guiding each cut against wheels of increasing fineness: stone, then lead, wood and cork and finally a mixture of water and fine powder.
Producers of lesser quality lead crystal polish cuts by dipping cut crystal into acid. Side-by-side, the difference is significant.
Glass engraving originated as artisan hand work and is not as invasive as hand-cutting. Both lead crystal and soda-glass can be engraved by guiding blank glass against revolving copper wheels that grind fine wheel marks into the glass, leaving a soft grey design.
Engraving is still done by hand but more commonly by machine. Machine engraved monograms on glassware is both popular and affordable.
Acid, applied by hand or by stencil for mass-production, bites or ‘etches’ into glass leaving a frosted design deliberately left unpolished. Etching resembles engraving but leaves no wheel marks on the glass.
A stenciled design is placed on glass to protect areas to remain untouched — and expose areas to be blasted away by a force of sand— leaving a textured design.
A film of mercury is poured between double walls of glass to look like brilliant silver.
Enameled glass is painted with oxides mixed with finely powdered glass suspended in oil. The design is permanently fixed in a low temperature muffle kiln. If paint pigments are not fixed with heat, they’re considered ‘cold colors’, which eventually wear off.
Decals are designs printed on film-coated paper with special paint which may be colorful and/or metallic. The paper designs are applied to the glass and fixed with heat in a process similar to ironing a decal on a t-shirt. Decals are commonly used to decorate barware and colorful glassware for children.
This technique requires a design to be first engraved on a copper plate which is inked. The ink is then transferred to paper and applied to the glass while the ink is wet. The same copper plate is used for duplication. All transferred designs on glass must be fixed with heat.
Even if fixed with heat, all glassware with applied ornamentation that is: metallic, painted, decals or transfer, should be washed by hand.
Pat Breen: EYEWITNESS TO QUALITY
MY NEXT POST: DRINK-WARE: STEMWARE & TUMBLERS