Thermal Styling

It's effects on virgin and chemically treated hair

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Thermal styling has been around for many years, primarily as a means of straightening and curling the hair. It has greatly increased the styling options of those with African descent textured hair, offering versatility and the option to wear virtually any and every hairstyle. With the advent of chemical hair relaxers and permanent waves, more enduring ways of achieving hair straightness and curls grew in popularity. Thus, thermal styling today is not as heavily depended upon for its mere ability to straighten or curl. Rather, heat is often used in conjunction with technologically advanced chemical systems, conditioning treatments and expert cutting techniques to deliver shape, movement, shine and a rich, silky texture to achieve an endless array of styles. In this discussion of thermal styling, it is important to establish the following:

1) Thermal styling, when properly implemented is a 'physical' phenomenon. Whether hair is being thermally straightened, waved, or curled, the effect is only temporary. When wet or exposed to humidity, the thermally straightened hair fibers revert to their original form.

2) Hair can only withstand a certain amount of heat before damage results. The scorching point of hair is estimated to be between the temperatures of 380° to 400° f. Even at the slightly lower temperatures, high heat is capable of:

a) Lanthionizing or breaking the cystine bonds of hair to a limited extent, slightly decreasing tensile strength.

b) Severely damaging or even significantly removing the cuticle layer, leaving the delicate inner structures of the hair exposed; and

c) Causing excessive hair dryness, brittleness and breakage. 

3) Hair texture and condition are important factors in thermal styling. Fine hair requires less heat than coarse hair. And generally, chemically processed and damaged hair cannot withstand as much heat as virgin hair that is in good condition. 

4) Thermal styling methods are to be evaluated in terms of their mechanical demands, as well as temperature. Certain thermal styling processes require a great deal of manipulation and impose tremendous mechanical stress upon the hair, which can be as damaging or even more so than heat itself. For instance, roller setting is not necessarily better than thermal styling; if the client's hair texture requires excessive roller tension, or if the hair is difficult to comb afterwards, then a curling iron may have been a better styling option. 

5) Deep conditioning treatments, using the appropriate kinds of conditioners, are essential when thermal styling. Heat is extremely drying to hair.Therefore, when styling using high temperature methods, make sure to deep condition with a good moisturizing or humectifying treatment before styling. This will help to counterbalance the moisture which thermal styling extracts from the hair. When hair shows signs of damage, make sure the conditioner also has some substantive proteinous agents. This will help fortify the cracks and weakened areas within and along the hair shaft, providing more support for the hair, while it is thermally treated. For blow drying, it is important to apply a styling product to help the brush or comb glide easily through the hair. There are some good silicone sealants and specifically formulated blow dry lotions that are excellent for this purpose.


The Most Prevalent Methods of Thermal Styling

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Hot combing or pressing is the most common method of temporarily straightening African descent hair. For effective straightening, pressing combs (whether conventional or electric) are heated to temperatures as high as 350°  F to 375° F. Typically, a small amount of creme, lotion or oil is applied to clean, dry hair in order to:

1) Help protect the hair against scorching

2) Give the pressing comb 'glide' (which reduces mechanical styling stress)

3) Control heat for advanced straightening

4) Impart shine 

It is very important for stylists to use only cremes, lotions or oils that have been purposely and expertly developed for pressing.


A Word About Thermally Styling Chemically Treated Hair 

Relaxed and color treated hair can be, and is being, thermal styled with excellent results. It's a fact that such hair has undergone chemical changes that involve cystine bond cleavage (or transformation), and a resultant decrease in tensile strength. If properly processed, however, the hair is still in reasonable condition and can withstand thermal styling. The key to maintaining good hair condition under these circumstances are:

1) Good and consistent conditioning

2) Temperature monitoring (remember that chemically processed hair requires less heat than virgin hair).

3) Keeping mechanical manipulation and styling stress to a bare minimum (combing and brushing while blow drying). It is also important that clients refrain from thermal styling on a day-to-day basis if healthy hair is a goal. Rather, wrapping, pin curling and roller sets are preferred methods of maintaining hairstyles until the next appointment. 

When it comes to permanent waved (curly permed) hair, thermal styling must be approached with this awareness: permanent waved hair will relax to a significant extent when thermal styled by any method. Many permanent wave systems on the market today claim to offer style variety and adaptability (from curly to straight back to curly again). This will work only to a limited extent and for a limited period of time. Whenever permanently waved hair is blow dried, thermal curled and/or roller set, the definition of the original curl or wave pattern will weaken significantly. With continued styling manipulation and exposure to heat, the curly style will not bounce back and may become difficult to style in any manner. Another factor when considering the thermal styling of permanent waved hair dryness. The active ingredient in permanent wave systems (ammonium thioglycolate), is very drying to African American hair. As previously pointed out in this article, heat, is also drying to the hair. When your clients want straight styles, it's best to allow the permanent wave to grow out, and to use a warm pressing comb until the hair is long enough to cut. At that time the virgin hair can be chemically relaxed. 


PLEASE NOTE: The temperatures of the thermal styling appliances noted in this blog post were determined in laboratory tests, involving a limited number of brands. The temperatures are not meant to represent all professional styling devices on the market.