Wagner and Griswold are the leaders in the American cast-iron collectibles market. Wagner Manufacturing started business in 1891 in Sidney, Ohio. It manufactured cast iron and tried other products over the next century, including brass and aluminum. Randall Company purchased Wagner Manufacturing in 1953, and Griswold, its biggest competitor, in 1957. Wagner Ware markings help identify the era of production, but because of reproductions, confirmation is necessary.
Look for the oldest Wagner items by name and patent dates. Wagner Manufacturing was the original company, and it used "Wagner Ware" in some markings by 1902. It also had Wagner Hollow Ware and had purchased the Sidney Hollow Ware Foundry in 1897. It sold the Sidney foundry in 1903, according to history by Griswold & Cast Iron Cookware Association (GCICA). Many items have patent dates in the mold, and this helps identify Wagner markings.
Watch for quality cast iron cookware. Wagner made molded cast iron with a polished exterior and interior, and the best production was from 1920 to 1940. An article in "The Kansan" reports that manufacturers of cast iron during that period polished it in a drum or turned it on a lathe to make cooking surfaces smooth.
Use the Google timeline to see different marks used and patent dates on the bottoms of some of the items. This is a source for learning nuances in the marks and acquiring information about new patent numbers. Some Wagner cast iron had "Wagner" in quotation marks, and "Sidney, O" was common. This mark bends around a circle, and the circle may contain a patent date.
Look for items marked both Wagner and Griswold. After Wagner purchased Griswold and both became part of Randall Company, Randall Company sold to Textron in 1959. In 1969, Textron sold both companies to General Housewares Corp. and it used both names on some items. These items are not very desirable in the eyes of collectors because they are not Wagner or Griswold products.
Watch for markings, boxes or information with "Wagner Corporation" because this is the group of investors that purchased Wagner foundry from General Housewares Corp. in 1997.
Look for reproductions and recognize the difference. Wagner Ware reproductions have markings just like the originals. The quality of the cast iron is not as good, the marks are not as clean and clear and the seams are not as smooth. Toy items are the most reproduced, according to the Griswold and Wagner website.