6.1 Wet styling & thermal styling

Building shape without chemicals

Hairstyling is the art of arranging hair into a finished form, and most of it depends on a simple bit of chemistry: the hydrogen bond. Hydrogen bonds are weak physical side bonds in the cortex that are easily broken by water or heat and re-form as the hair dries or cools. Because they are physical rather than chemical, every wet set, blow-dry, and iron curl is a temporary change — the style reverts the moment the hair absorbs moisture from humidity or perspiration. This is why a stylist can completely reshape hair one day and return it to its natural pattern with a shampoo the next, and it is the single idea the NIC theory exam tests most often in this domain.

Finger waving and pin curls

Finger waving shapes wet hair into alternating ridges and hollows (troughs) using the fingers, a comb, and waving lotion — traditionally a karaya-gum gel that keeps the hair pliable while it dries. Because the set is created only by drying hair into a new position, it is called a cohesion (wet) set.

Pin curls are the building blocks of a wet set. Every pin curl has three parts:

• Base — the stationary foundation, the panel of hair on which the curl is placed.
• Stem — the section between the base and the first arc of the circle; it gives the curl its direction and mobility.
• Circle (loop) — the part that forms the curl itself; its size determines the width of the finished wave.

The stem controls movement. A no-stem curl is placed directly on its base for the tightest, longest-lasting, least mobile curl; a half-stem curl permits medium movement; and a full-stem curl gives the greatest mobility because the loop sits farthest from its base. Base shapes — rectangular, triangular, arc, and square — are chosen to prevent splits in the comb-out, and open-center curls produce even, uniform waves while closed-center curls produce waves that grow smaller toward the ends. Ridge curls are pinned in staggered rows to create waves; skip waves alternate a finger wave with a row of pin curls; and cascade (stand-up) curls and barrel curls are pinned upright to build height and volume where a lifted style is wanted.

Rollers and volume

Rollers do the same job as pin curls but faster and with more staying power: one roller equals about two to two-and-a-half stand-up pin curls. The volume a roller creates is set by how the strand is held relative to its base — the panel of hair the roller rests on, generally the length and width of the roller itself.

Larger-diameter rollers create larger, looser waves; smaller rollers create tighter curl.

Backcombing and backbrushing

To add height and lock a set together, stylists tease. Backcombing (also called teasing, ratting, or French lacing) combs short sections from the ends down toward the scalp so the shorter hairs mat at the base and form a soft cushion. Backbrushing (ruffing) uses a brush to push those shorter strands toward the scalp, building a light cushion that blends the surface hair for a full, upswept effect.

Blow-dry and thermal styling

Blow-dry styling dries and shapes hair in one operation. A concentrator nozzle focuses the airflow for smoothing and precision, while a diffuser disperses the air to dry curly hair without disrupting its natural curl pattern. Brush choice controls the result: a round brush adds curl, wave, and volume, and a large flat paddle brush smooths and straightens longer hair.

Thermal styling shapes dry hair with heat instead of water. Thermal (marcel) irons and curling irons form curls and waves, and a flat iron straightens by pressing hair between heated plates. Heat breaks hydrogen bonds just as water does, so the change is still temporary.

Hair pressing (silking) temporarily straightens overly curly hair with a heated pressing comb:

• Soft press removes about 50-60% of curl (comb passed once on each side).
• Medium press removes about 60-75% (once on each side with slightly more pressure).
• Hard press (double press) removes 100% (comb passed twice on each side).

Because pressing only manipulates hydrogen bonds, humidity and perspiration return the curl. This is different from thermal reconditioning (Japanese straightening), which uses a chemical to break the disulfide bonds and a flat iron to reset them — a permanent change, not a heat-only style.

Heat safety

Test a stove-heated pressing comb or iron on white cloth or tissue paper before it touches hair; scorch marks mean it is too hot. Place a hard-rubber comb behind the iron to shield the scalp, lower the temperature on fragile, porous, or chemically lightened hair, and remember that burnt hair cannot be reconditioned — prevention is the only remedy.