Why should hair be completely dry before thermal curling or pressing?

Why should hair be completely dry before thermal curling or pressing?

• A. Wet hair expands and may break when exposed to heat
• B. Wet hair dries faster with heat
• C. Dry hair expands
• D. Heat has no effect on moisture

Answer: (A)

Moisture inside hair is the key factor here. When heat is applied to wet hair, the water trapped in the shaft wants to turn into steam. That rapid vaporizing creates internal pressure, which can lift the cuticle, cause swelling, and lead to breakage, frizz, and uneven curl or press results. Dry hair, with no moisture to vaporize, heats more predictably, allowing the cuticle to lay flat and the styling tool to work evenly. There’s also less risk of steam scalding or weakening the strand when you’re handling the iron or comb. So drying completely before thermal curling or pressing minimizes damage and gives cleaner, more durable results.

Moisture inside hair is the key factor here. When heat is applied to wet hair, the water trapped in the shaft wants to turn into steam. That rapid vaporizing creates internal pressure, which can lift the cuticle, cause swelling, and lead to breakage, frizz, and uneven curl or press results. Dry hair, with no moisture to vaporize, heats more predictably, allowing the cuticle to lay flat and the styling tool to work evenly. There’s also less risk of steam scalding or weakening the strand when you’re handling the iron or comb. So drying completely before thermal curling or pressing minimizes damage and gives cleaner, more durable results.