Never used them; my hair is naturally poker straight. These tips might help you out:
10 Flat Iron Success Tips – Tips on How to Flat Iron Your Hair
1. Begin with Well-Conditioned Hair
Before you even turn on that flat iron, ask yourself this: is my hair well-conditioned and moisturized? If it's not, turn that iron off and tend to your hair first. Sometimes, we think that a good heat protectant product is supposed to do all the work, but that's not true. You have to do your part to make sure you're only heat styling hair that's in a condition to take all of that heat without doing further damage. Only flat iron hair that's been regularly conditioned and cared for; otherwise, applying heat to dry, brittle hair is only prolonging the inevitable--a major cut.
2. Flat Iron Clean Hair
The best time to flat iron your hair is immediately following a fresh shampoo and condition (and deep condition if necessary). You have to press clean hair; applying heat to hair that has products and dirt in it is doing nothing more than baking these old products and dirt in. Need a touch up during the week? Flat iron once more, with minimal heat, but that's it; flat ironing is not for every day.
3. Use Smoothing Balm or Serum
After shampooing and conditioning, apply a smoothing balm or serum to your hair. This helps much more if your hair is chemical-free, but relaxed ladies can benefit from it, too. Look for humidity-resistant formulas if you live in a climate where humidity makes a frizzy mess of your straightening work as soon as you step out the door.
4. Use Heat Protectant
Once your hair is dry, apply a heat protectant to each section of hair before you flat iron it. Don't get fooled, though--a heat protectant helps, but even the best brand won't hold up to heat that's too high.
5. Avoid Oil Before Ironing
Applying a natural oil after
you iron is fine. Sometimes you need a little weight afterward, but don't put oil on your hair before
you press it. You won't get that lightweight, bouncy look you're after.
6. Only Flat Iron Dry Hair
For the best, longest-lasting results, only flat iron completely dry hair. Does this mean you have to blow dry it straight first? Not necessarily. You can always wet wrap your hair and sit under a hood or bonnet dryer until it's dry--this is a gentler drying method and the wrapping technique smooths your hair just like blow drying would. You can also let your hair air dry until it's about 80% dry, and then blow dry it the rest of the way. Flat ironing hair that's not completely dry will cause it to frizz up.
7. Go Slow and Steady
Try not to flat iron when you're in a hurry. This is a technique that requires slow, controlled movement, but don't let the iron sit in one place for any length of time. Move it, but don't rush it. Begin as close to the roots as you can and pull the iron down in one smooth motion. If you hurry through it, you may have to go over that section again (and again). Remember: the less heat, the better. Making one good pass is better than making three or four mediocre ones.
8. Adjust the Temperature as Needed
Just because your iron heats up to 450 degrees doesn't mean every part of your hair requires that much heat. For women with natural hair, finding out that they have two or three different textures on one head may be a shock, but it's not uncommon. Your crown area may be the curliest section, requiring high heat, but the hair on the sides of your head may be straighter, so turn the heat down when pressing that section.
9. Iron Small Sections
Smaller irons (1 1/2 inches or less) are better for tackling small sections of hair. Try not to press pieces wider or thicker than 1 inch at a time. You'll do a better job of straightening the entire section when you don't have to deal with too much hair. Big, chunky sections won't straighten properly.
10. Wrap Hair at Night
Now that your flat ironing job is complete, don't ruin all your hard work with no night time care! Wrap your hair at night and cover with silk or satin before bed. This way, your morning routine consists of little more than taking your hair down and combing through it. You already have the slight curve and volume and no more heat is required.