Straightening Curly Hair and DamageQ: If someone has naturally curly hair, very tight ringlets, would it permanently damage the hair if a flat iron and straightening cream were used for less then 12 hours? I'm doing a friends hair in a week and she has very small curls. I'm afraid of damaging her hair.
A: Provided that your friend's hair is in healthy condition to begin with and you are using a product that doesn't chemically alter the wave pattern of the hair (most off the shelf hair straightening products don't) there is no worry about straightening the hair using a flat iron and product as you describe.
If you're concerned about the condition of her hair (if it feels rough, dry and brittle) then you should make sure to address those concerns before styling it. Even if the hair feels normal, you should consider giving her a deep conditioning treatment beforehand, rinse it out thoroughly and apply the straightening cream to the damp hair before drying it with a blow dryer.
If you dry the hair correctly, you will remove most of the curl and make the flat iron process easier to accomplish. If her hair is long, or particularly thick, be sure to section her hair first and dry it in sections. This allows you more control of the hair while drying and ensures that the hair gets completely dry (which is a key part of flat iron styling or other heat styling techniques).
You then want to section the hair again before you begin using the flat iron. Again, this makes longer and thicker hair easier to work with and will give you better results. Be sure to iron the hair in thin slices, to allow for even heating and straighter results.
Since you specify that her curls are natural, it is less likely that there will be cause to worry about damage. If instead you had said her curls were the result of perming, I would caution you about the fact that her hair would likely be very porous and would need extra protection during the heat styling process.
You do still need to be careful to avoid burning the hair. Make certain that her hair is completely dry before you use the flat iron. Applying a hot flat iron to hair that is still damp can literally cook the hair and can make it brittle. Once you are certain the hair is dry, you need to test your iron before applying it to the hair. Take a piece of tissue paper (either the kind used for gift wrapping, or perhaps an end paper for perm wraps. Spray it with water to moisten it and place it between the heating plates of the flat iron and press for 10 seconds.
The paper should come out dry and smooth with no scorching or discoloration. If there is any discoloration present or if the tissue smokes when pressed in the flat iron, the temperature is too high and should be reduced and retested after giving time for the temperature to adjust. Once you know your flat iron is at the right temperature, you can proceed to flatten the hair. In addition to the straightening cream, you can lightly mist each segment that you iron with hairspray to help the hair stay straight longer.
I wish you all the best.
Flat iron styling
Heat styling basics
How to recognize damaged hair