If you have curly hair and just can't find hair extensions that are curly enough to match your natural hair, consider perming them. Keep in mind that only human hair extensions that have not been treated with a hydroxide-type relaxer or have been colored with a metallic dye can be permed. The process for perming human hair extensions is identical to that of applying a permanent solution to your own natural hair.
Select your perm solution. If you are looking for a tight curl, go with an alkaline-based solution. If you want softer curls or extensions with body, choose an acid-balanced solution.
Apply a creme conditioner to the hair extensions.
Put on plastic gloves to protect your hands against the harsh chemicals.
Mix and apply permanent solution to hair extensions according to the directions included with the hair product.
Wrap the extensions around the hair rollers. Make sure that the hair is wrapped smoothly without stretching it too tightly.
Rinse the permanent solution out completely using warm water.
Apply the neutralizer product that came with the perm product directly onto the hair extensions.
Let hair extension sit in curlers for five to eight minutes in order for the curl to take hold.
Remove the rollers and rinse the neutralizer off of each hair extension with cool water.
If you haven't already purchased hair extensions or don't mind buying another set, look for hair extensions or even clip-in hair extensions that already come curly. Take extra care to find extensions that match the texture and wave pattern, not to mention the color, of your natural hair.
If your hair extensions are dark in color, be mindful that any permanent solution containing hydrogen peroxide can change the hue of the hair color. In fact, dark hair extensions may transform into hair extensions with reddish highlights.