A hair dryer (or blow dryer) blows cool or hot air to dry wet or damp hair. On the other hand, a hair iron is a device that changes the structure of hair using heat delivered through heating coils covered by a ceramic, Teflon or titanium coating.
A hair dryer is used for quicker drying of hair and better control over shape and style of hair. Styles with blow drying create volume and discipline (staying power). Dryers can have different blow drying power; some hand-held dryers can even be as powerful as the industrial hand dryers found in public restrooms.
There are three types of hair irons depending on the desired end result:
- A hair straightener is shaped like a tong with flat inner plates with a heating coil beneath that when clamped and run down the length of the hair straightens it.
- A curling iron is shaped like a barrel or cone and hair can be curled around it. Curling irons can be used to create curly styles out of naturally straight hair, or to change the shape of naturally curly or wavy hair. Modern curling irons also use ions and infrared heat to reduce frizz and give hair a smoother appearance.
- A crimping iron crimps hair or makes it wavy in a sawtooth shape similar to when hair is braided and then unbraided – a style popular in America in the 1980s. Crimped hair should not be brushed or it will frizz out.
The hair dryer has a heating coil and small fan. The heating coil is designed to heat quickly using its electric resistivity and an electric current. The small fan is motorized and is used to blow the heated air generated from the heating coil through the barrel (the tunneled end of the hair dryer) that houses the heating coil and the opening for the air to blow out. The heating coil is made of nichrome (an alloy of nickel and chromium) and is installed on an insulating board. Because nichrome is a poor conductor of electricity and does not oxidize when heated, it is the perfect choice to use for the heating coil. The hot air of a hair dryer accelerates the evaporation of water to dry the hair faster. This controls the formation of hydrogen bonds in each strand of hair that holds shape better. Hair needs to be dried with a hair dryer before using a hair iron.
Straighteners have flat ceramic heating plates shaped like tongs that apply constant heat to the hair. This breaks down the hydrogen bonds that give the hair waves or curls. Once the bonds are broken, hair is prevented from holding its original shape unless exposed to moisture or humid conditions.
Curling irons have ceramic, Teflon or titanium barrel or cone around which hair is wrapped and curled. The hair when heat treated is more malleable.
Crimping irons and curling irons can curl or crimp hair because hair is essentially a long string of protein, acting like wood fiber. If you heat wood, it becomes malleable and you can form it and shape it. The process of heating the hair and curling it around the curling iron makes it keep that form until it is wet, when it once again takes its natural shape. The temperature range that actually curls hair is fairly small, so all curling irons operate with close to the same amounts of electricity.
To reduce hair damage hair should be air dried with a towel before using a blow dryer. Sometimes a leave-in conditioner or moisturizer can be used. The blow dryer is held approximately 8 to 10 inches away from the hair. Positioning the appliance closer to the hair can cause damage to hair or burn the skin on your scalp, face and ears. Slowly move the hair dryer as you dry your hair. You should avoid leaving one section of hair exposed to heat for too long a period. Blow the air from the roots of your hair to the ends to achieve a smooth, sleek look. For a rough, tousled look, blow the air from the ends to the roots. A hair brush can be used while blow drying.
When using a hair straightener the hair after washing is gently blow dried and a hair straightening spray is applied on a small section. Once the device is plugged in and has heated up, this small section of hair is then placed between the tongs of the open hair straightener and closed shut. From the top on your hair or crown, with the hair straighten now closed, slide the straightener all the way down to the ends of your hair. Crimping and curling irons have ceramic, Teflon or a titanium coating. For crimping The hair is usually sectioned off into four and a heat activated styling product is applied that will protect the hair from any damage that the hot crimping iron may cause. The crimping iron is placed close to the scalp (but not touching it) and the iron is pressed to closed. After several seconds the hair is released from the iron. You work your way down the strand until the entire section is complete.
A curling iron is an electrical cylindrical device with an attached hinged clamp that uses heat to form hair into curls. Dry hair is usually clamped at the end, then wrapped around the heated metal or ceramic rod and held in place until the hair molds to the proper shape. Smaller size curling iron barrels create tighter curls, while large diameter barrels create loose curls or waves.
Hair dryers can come with a diffuser attachment which help to distribute heat evenly over the entire head and help to encourage and tame curls while drying the hair. The curling iron can also have either a spring-loaded, Marcel, or clipless handle. Spring loaded handles are the most popular and use a spring to work the barrel's clamp. They are less expensive and more user-friendly than other models, but they are fragile and can cause a crimp where the clamp is placed. When using a Marcel handle, named after Marcel Grateau, one applies his or her own pressure to the clamp. For this reason, they are more difficult to use, and they are usually used only by professional stylists in salons. Clipless wands have no clamp, and the user simply wraps hair around a rod. Most clipless curling irons come with a kevlar glove to avoid burn
The hair dryer was invented at the end of 19th century by Alexander Godefoy in France in his saloon. Hand held dryers entered the home in 1920.
The modern hair straightener is credited to Scottish heiress Lady Jennifer Bell Schofield, who refined and combined previous efforts into a hinged, two-plated heated iron in 1912.n 1972, the modern crimping iron was invented by Geri Cusenza.
Curling irons have been used for all of recorded history, to shape and curl hair, beards, bangs and wigs. They go all the way back to ancient Babylonians and Egyptians and nobles in classical Greece when metal tongs were heated over an open flame and applied to the hair. Hiram Maxim, inventor of the Maxim machine gun and hundreds of other patents, filed a patent for a improved curling iron in 1866. In 1959, the French company BaByliss (now owned by Conair) invented and produced the first electric curling iron.
While hair is fairly resilient, heat treatments such as a hair dyer can cause weathering of hair to speed up. Weathering is where the cuticle of the hair shaft begins wearing away, exposing the cortex and causing the shaft to break. The intense heat can cause split ends, dull or frizzy hair, and occasionally the hair can become brittle, break off or burn. The use of hair straightening products, and heat-activated sprays are meant to protect hair from heat damage caused by these styling devices.