I often get asked questions about perm rods and what sizes are appropriate for different
lengths of hair. People often want to have really simple “Tab A/Slot B” answers to their questions, when unfortunately this isn’t
always possible. “Choosing Perm rods” is one of those subjects that requires a little “finesse” when it comes to choosing the right
one. The size of the perm rod you need to use depends largely on the length of the hair being permed and the amount of curl you want
to have in the finished style.
We all know that the different sized rods create different sized curls in the permed hair.
The smaller a rod is the smaller and tighter the curls will be as a result. In addition, the length of the hair is a factor in the
resultant amount of curl that is achieved from a perm.
Curl vs. Wave vs. Body
We’ve all heard the terms “Body Wave” and “Body Perm” and “Curly Perm”, and in fact, a lot
of the time the use of such terms is confusing. Most people don’t understand what is meant by these terms and how the use of certain
perm rods factors in creating these effects. The principle is simple: the more times the hair is wound around the perm rod, the more
bends are created in the hair.
The longer the hair is the more times it will need to wrap around a rod of a given size.
In order to create a wave that looks natural and balanced to the hair’s texture and length, we generally use larger rods on longer
hair lengths. This depends on the desired outcome. Say we have a client who has neck-length, layered hair and she wants a lot of
volume and curl in the hair. Her hair is an average of 5 inches long in its shortest areas. Depending on how tight a curl was
desired we’d probably use a gray or white perm rod to wrap the hair. If she wanted less curl and just “body” we’d probably use a
purple rod to create the largest and softest wave pattern.
With shorter lengths, using large rods can give large, soft curls and add wave instead of
curl. The shorter the hair is, the smaller the range of rod diameters that we would be likely to use would be.
The Rods Themselves
Perm rods are designed on a universal standard. The various sizes are color-coded, even
though the manufacturers may use shades of the same color that vary from other manufacturer’s rods of equivalent size. The key is to
learn what basic colors mean, since some of the rods may not be readily visible as being different in size.
(It should also be noted that perm rods come in both concave and “straight” versions. The
concave rods get slightly thinner toward the center and flare at the ends. This has two benefits. One, it allows the rod to sit
snugly against the scalp with hair wound around it – to a point at least. And two, it gives a slight variance in the curl making it
looser to the outside of the segment for a more natural look. The straight rods have the benefit of creating a uniformly shaped curl.)
Let’s take a look at the rod color groups: (Listed lengths are approximations, not meant to be hard rules.)
(Click to enlarge)
Red: Red rods are the smallest rods made, and are typically only used on
short hair lengths to create tight, kinky curls. The hair lengths that would most often require such small rods are those less than 2 to 2-1/2 inches.