TierraCast offer both wire products and cast pewter components. Pewter is a metal alloy, traditionally between 85 and 99 percent tin, with the remainder consisting of copper and antimony acting as hardeners. Lower grades of pewter may contain as much as 60% lead, giving them a bluish tint.
TierraCast uses an alloy called Britannia, composed of 92% tin, 7.5 % antimony and .5% copper. Tin is refined from ore that contains other metals, including lead. A chemical process is used to remove the lead, but trace amounts still remain. Although all pewter contains trace amounts of lead, the term "lead free pewter" is used to describe pewter that meets the stringent FDA standard of less than .05% (or 500 parts per million) lead content in pewter in contact with food.
TierraCast Plated Finishes
The electroplating of Tierracast cast pewter components is done by standard industry methods. First, thin layers of various metals are deposited on the surface by immersing them in an electrolyte solution and passing an electrical current through them. While each plated part receives various layers, the final surface offered by TierraCast is one of four common types.
•Gold Plate of 22k quality is used on TierraCast parts. 22 carat gold formulated to an 18 carat colour and a medium luster finish is used on all of the cast parts. All gold plated thicknesses are above 10 millionths of an inch and thus qualify under the Federal Trade Commission terms of "Gold Electroplate." The plate thickness is sufficient to withstand reasonable wear and tear, but is not so thick as to resist aggressive cleaning or machine polishing. Any cleaning should be done with mild detergents and a soft cloth.
•Silver Plate is done using .999 Fine Silver as the final plated surface, and has a thickness of at least 20 millionths of an inch. Unlike gold, this plated metal surface is susceptible to tarnishing but may be brightened by softly rubbing with a jeweler’s polishing cloth. Abrasive silver paste polishes should not be used.
•Rhodium Plate is often used as a "silver coloured" alternative to real silver plate. While more gray in color than silver, Rhodium is highly scratch resistant and does not tarnish.
•Copper Plate is applied in thickness sufficient to allow for chemical antiquing and machine relief to give the plated parts a natural antique look. Like silver plate, it is susceptible to natural tarnishing as well and may be brightened using a soft polishing cloth.
•Antiquing is the process of artificially inducing (or mimicking) the natural process of the tarnishing of metals. Depending on the plate type, parts are either darkened with chemical solutions or with specially formulated metal marking inks. Both approaches are carefully monitored to achieve a consistent appearance that creates polished highlights and dark contrasting recessed areas.