To choose the best cast iron trivet, collectors should examine the casting marks on the back of the piece, the length of its legs, and its overall shape and pattern. These key indicators can identify the age and origins of most trivets. Casting marks are often used to determine the manufacturer of the piece. The length of the legs can help locate in which century the piece was cast, while the overall shape can further pinpoint its exact age.
Trivets were originally invented to aid in household cooking. They were designed of wrought or cast iron to withstand the intense heat generated by a cooking fire. The trivet was placed on top of the hot coals of the fire with its three long legs nestled deep for full support. Cooking pots were then placed on top of the trivets just out of reach of the coals. This kitchen accessory continues in use in modern kitchens as a cooking utensil, wall decoration, and table top protector.
An antique cast iron trivet may be identified by its casting marks, typically located on the underside of the piece. The hot, molten form of this metal was poured into preformed molds that created the final shape of the trivet. The manufacturer would often mark the casting mold with his brand or symbol, which would then appear stamped on the cooled product. Collectors of these items may wish to begin by searching for complete sets of trivets cast by particular manufacturers as identified by the seal on the back. Online auction sites, estate sales, and thrift stores are excellent locations to begin searching for unique pieces that can be added to this type of collection.
Several different factors may be used to identify the age of a cast iron trivet, such as the length of the support legs, their shape, and the condition of the surface of the metal on the plate portion. Longer legs of 1.5 inches (3.81 centimeters) or more are typically indicative of an older model and make. Legs that are square, rectangular, or "T" shaped may also identify the item as one that was in use prior to 1890. These trivets often show signs of black dust that has settled into the niches of the surface of the plate, as opposed to the orange rust that tends to accumulate on more modern designs. Collectors may use these indicators on items that are not marked with a manufacturer's seal to determine whether a piece is a genuine antique or a modern reproduction.
The shape of the cast iron trivet may be used as a final determination on age and value in a collection. The most common shape for a trivet is the three sided triangle. Trivets were first made of wrought iron, which was difficult to bend and shape, and could more easily be adapted into this easy shape. The transition to cast iron as a base material allowed for more detailed designs to be created, and allowed metal workers to move away from the more common triangular set. These items may be found in the virtually any shape and size, and may feature a motto, political slogan, or advertising campaign, depending on their date of issue.