Chemical Services: Waving, Relaxing, and Texturizing
Chemical services: waving, relaxing, and texturizing
This domain tests the chemistry of breaking and reforming hair bonds, the difference between wave and relaxer products, and the safety checks that prevent burns and breakage. Expect questions on processing, neutralization, retouch rules, and contraindications.
Waving
- Cold waves use thioglycolate to reduce disulfide bonds; the hair is wrapped, processed, rinsed, and neutralized.
- Neutralizer, often hydrogen peroxide or sodium bromate, rebuilds disulfide bonds and stops the wave. Incomplete neutralization leaves the hair weak and over-processed.
- A test curl predicts curl size and processing time. Do not shampoo for about 48 hours after a wave, and do not wave over damaged hair or an irritated scalp.
Relaxing and texturizing
- Sodium hydroxide relaxers are lye products with high pH; no-lye relaxers use calcium hydroxide or guanidine. Both break disulfide bonds but require different care.
- Protect the scalp with base, apply to new growth only during a retouch, and never pull relaxer through previously relaxed hair.
- Process for the manufacturer's time, rinse thoroughly, and use neutralizing shampoo until the indicator shows the relaxer is removed. Then condition.
- Texturizing uses a weaker process to loosen rather than straighten; it still requires a strand test and careful timing.
Worked example
A client with a sodium hydroxide relaxer returns with 1 inch of new growth and wants a retouch. Reasoning: the relaxer should be applied only to the new growth, with protective base on the scalp and previously relaxed hair protected. Applying product through the ends would overlap and over-process them, causing breakage. The barber should strand-test, time precisely, rinse, neutralize, and condition.
Traps
- Applying relaxer to the scalp without base or to broken skin.
- Rushing neutralization; relaxer residue continues to process.
- Using a thio wave on hair that has had a hydroxide relaxer without a compatibility test.
- Shampooing immediately after a wave.