Why your flat iron needs several passes: dry hair and 1.5" × 0.5" sections

Sign one: you press, and it springs back

Hair that is even slightly damp at the root or in the middle of a thick section won't stay flat. The manual is clear: the iron is for dry hair only. Hair that feels dry on the outside can still hold water underneath, especially on dense or coily hair after wash day. Pressing it does two bad things: it doesn't stay straight, so you go back again, and every extra pass is more heat on the same strands.

How to check

• Blow-dry until the roots and the inside of each section are dry, not just the surface.
• If you see steam, hear a sizzle or smell burning when the plates close, stop — the hair is still damp. Dry it first.

Sign two: the outside is smooth, the inside is not

The other usual cause is a section that is too big. The plates press the hair that touches them; hair in the middle of a thick section gets less heat and less tension, so it comes out wavy and you go back over it. The instruction manual gives the size: sections about 1.5" wide and 0.5" thick.

• 1.5" wide keeps the whole section inside the plates.
• 0.5" thick lets the heat reach the middle of the section in one pass.

It feels slower to take more, thinner sections. It is faster overall, because each one is done in one pass.

One slow pass

1. Clip the rest of the hair away and take one 1.5" × 0.5" section.
2. Comb it smooth, close the plates near the root and glide down at a slow, steady pace to the ends.
3. Check it. Smooth? Move on. Not smooth? Raise the temperature one step with the + button (the LCD shows the setting) rather than going over it again and again.
4. Repeat across the head in the same order every wash day, so no section is missed or pressed twice.

Which plate width for which part of the head

The 2" Titanium Wide moves through long, thick lengths: the plates are wider than a 1.5" section, so the whole section sits inside them, and the back and sides go quickly. The 1" Titanium Classic is easier around the face, the crown, bangs and shorter layers, where a wide plate is awkward. The Salon Pro Duo has both for $89.99 ($101.98 if bought separately), in stock in the US.

Both have titanium plates, an LCD temperature display with +/− buttons, a 360° swivel cord that turns as you work around the head, and an ergonomic grip.

Quick checklist

• Hair 100% dry — roots and inside included.
• Sections about 1.5" wide × 0.5" thick.
• Comb ahead, one slow pass, then move on.
• Turn up one step only if a section isn't smooth.

For the comb technique itself, see the comb-chase method; for where to set the dial, see the temperature chart.