Pam Spaulding from Pam’s House Blend and Pandagon did a really interesting video interview for a project called Hair Stories.
You can read more about it on her blog (sorry, I can’t get the embedded video to work):
I am old enough to have experienced the “pleasure” of the thermal hot comb — you rested it over the gas flame of the stove to heat it up. Then the oil was carefully applied to your hair and that comb sizzled through the kinks till it was bone straight, hissing as you prayed the comb didn’t touch your scalp. This is what black women did to emulate straight hair. I say emulate because all it took was water or merely a humid day to revert the hair back to its natural state. But that was the only acceptable style for the working black woman working in the dominant culture.