With the heat and the weight of the ironing plate, the fibers are stretched and the fabric maintains its new shape when cool.
Some materials such as cotton require the use of water to loosen the intermolecular bonds. Many materials developed in the twentieth century are advertised as needing little or no ironing.
The electric iron was invented in 1882 by Henry W. Seeley, a New York inventor. Seeley patented his “electric flatiron” on June 6, 1882 (patent no. 259,054).
History
Metal pans filled with hot water were used for smoothing fabrics in China in the 1st century BC.
From the 17th century, sadirons or sad irons began to be used. They
were thick slabs of cast iron, delta-shaped and with a handle, heated in
a fire. These were also called flat irons.
A later design consisted of an iron box
which could be filled with hot coals, which had to be periodically
aerated by attaching a bellows. In Kerala in India, burning coconut shells were used instead of charcoal, as they have a similar heating capacity.
This method is still in use as a backup
device since power outages are frequent. Other box irons had heated
metal inserts instead of hot coals.
Another solution was to employ a cluster
of solid irons that were heated from the single source: as the iron
currently in use cools down, it could be quickly replaced by another one
that is hot.
In the late nineteenth and early
twentieth centuries, there were many irons in use which were heated by a
fuel such as kerosene, ethanol, whale oil, natural gas, carbide gas as
with carbide lamps, or even gasoline.
Some houses were equipped with a system of pipes for distributing natural gas or carbide gas
to different rooms in order to operate appliances such as irons, in
addition to lights. Despite the risk of fire, liquid-fuel irons were
sold in U.S. rural areas up through World War II.
In the industrialized world, these
designs have been superseded by the electric iron, which uses resistive
heating from an electric current. The hot plate, called the sole plate, is made of aluminium or stainless steel.
The heating element is controlled by a thermostat
which switches the current on and off to maintain the selected
temperature. The invention of the resistively heated electric iron is
credited to Henry W. Seeley of New York in 1882.
In the same year an iron heated by a carbon arc was introduced in France, but was too dangerous
to be successful. The early electric irons had no easy way to control
their temperature, and the first thermostatically controlled electric
iron appeared in the 1920s. Later, steam was used to iron clothing.
Credit for the invention of the steam iron goes to Thomas Sears.
