Dover Manufacturing Company, Canal Dover, Ohio
These sad irons, circa 1900, featured an asbestos lining (under a removable hood) which prevented heat from traveling up into the handle.
The Flood of 1913, the greatest natural disaster in Ohio history, severely damaged the Dover Manufacturing Company.
It's unsure when the last Asbestos sad iron was produced, but by 1916 Dover was experimenting with electric irons. Company ceased to exist in 1936 when bought by Knapp-Monarch.
See also: Asbestos Toy Irons
Examples of companion Ober Sad Irons in full and toy sizes. Most of the wooden handles are detachable. The pointed oblong irons are sleeve irons.
Vintage Machinery.org lists a number of Ober Manufacturing Company Patents including three for sad-iron handles.
This patent model shows that the body of the iron was cast hollow and was later filled with material that was a non-conductor of heat, such as plaster of Paris, cement or clay. Mrs. Potts claimed in her patent that this material held the heat longer so that more garments could be ironed without reheating the iron.
Mary Potts received a series of patents for variations on her iron. Some patents also were reissued. This item is part of the Homer Blair Patent Model Collection on exhibit at the Franklin Pierce Law Center Intellectual Property Library in Concord, New Hampshire.
Description: Sad Iron, U. S. Patent 113,448, April 4, 1871, Mary Florence Potts, Ottumwa, Iowa. The invention is a detachable handle for pressing irons. This permits a person to heat a number of iron bodies on a stove, attach the handle to one and iron with it until it cools, then attaching it to another heated iron body.
The model is 8" x 5" x 6" and has a metal body with a smooth bottom, a gold colored metal latch, and wood handle. The body is filled with a white non-conducting material, perhaps Plaster of Paris. The name "Mary Florence Potts" is engraved in script. This model is in very good condition.
This is the famous Mrs. Potts' Sad Iron that was widely manufactured and licensed in the United States and Europe. Her picture was featured in advertising. Her iron was exhibited in the Centennial Exhibition at the Smithsonian and also in the 1976 Bicentennial Exhibition. Mrs. Potts' iron is well known by antique dealers and collectors.
Google Patent Information for the 1871 Mrs. Potts Iron.
See also Mrs. Potts' Victorian Trade Cards.