Message: I am a technician in a hospital and our scrub colors are often being changed. I would like to know what to use for 65% polyester/35% cotton. The color now is honey, and I need to dye them navy blue. Do I need sodium chloride also? I have washed them in bleach.  Thank you.

It's better to buy 100% cotton scrubs if you want to dye them. Dharma Trading Company sells a couple of designs of 100% cotton ready-to-dye scrubs at their website. Since they can be dyed at room temperature with high quality fiber reactive dyes, 100% cotton scrubs are far more satisfactory (and cheap!) to dye.

Unfortunately, in comparison, your 65% polyester scrubs will present a problem. The cotton portion of the fabric cannot be dyed with polyester dyes, while the polyester portion cannot be dyed with cotton dyes. In order to get any dark or intense color, such as navy blue, you will have to dye both the cotton and the polyester, using different dyes. If you use only cotton dyes, you will get a pastel color, as only 35% of the fiber will take the cotton dye. 

You will not be able to buy polyester dye locally. All-purpose dye will not work. In order to dye polyester, you must mail-order some special polyester dye, called disperse dye. See my page, "Dyeing Polyester with Disperse Dyes".

While it is possible to dye both the polyester and the cotton, dyeing the polyester in your scrubs will require extensive boiling, and you must stir frequently throughout the boiling step, in order to obtain a solid color. You cannot dye polyester at room temperature, or even in hot water; you must boil the fabric in the dye for half an hour or longer. You will need a large stainless steel or enamel pot to do the dyeing, large enough for the fabric to move freely as you boil it in the dye. Do not plan to reuse this pot for preparing food, because clothing dyes will contaminate cookware. A good several-gallon dyepot is expensive; it's an excellent investment if you plan to do a lot of dyeing, but costs too much (typically $100) for a one-time project.

If you have a good dyeing pot, you will be able to dye the cotton and the polyester in two separate steps. You also have the option of buying Jacquard Products' dyes for polyester and cotton. Their dye for cotton is called "iDye", while their dye for polyester is called "iDye Poly". If you buy both iDye and iDye Poly, you can mix the two kinds of dye, in order to dye both the cotton and the polyester in your scrubs at the same time. I recommend that you follow this with a commercial dye fixative such as Retayne, because otherwise the direct dye will fade relatively quickly from the cotton. Retayne, like iDye Poly, must be ordered by mail, because you will not be able to find it in any local store.

Unlike dyeing poly/cotton blends, dyeing 100% cotton is easy to do without a dyeing pot, because there are cool water dyes available for dyeing cotton. The same dyes that are used in a good tie-dyeing kit work very well for dyeing cotton solid colors. I don't recommend the use of all-purpose dyes, such as Rit or Tintex dyes, on cotton, because they tend to fade quickly, and they bleed badly in the laundry, but if you acquire a good fiber reactive dye, such as Procion MX dye or Tulip One Step Fashion Dye, you can dye cotton scrubs any color you like. Fiber reactive dye will last much longer in cotton fabric than all-purpose dye such as Rit or Tintex, or direct dye such as the non-Poly iDye.

Sodium chloride (ordinary table salt) is useful for some types of dyeing, but you should use it only if your recipe calls for it. For any dyeing, find a good recipe for the exact dye and fiber type you are dyeing, and follow it closely. Your dye should come with instructions; if so, they will tell you exactly what, if anything, to add.

Bleaching 65% polyester scrubs is, unfortunately, not a very good idea. Chlorine bleach tends to damage polyester, often producing an ugly yellow color that cannot be removed in any way. Instead, it is best to use a chemical specifically marketed for removing dye. The easiest to find is Rit Color Remover, which is available in many grocery stores and pharmacies, as well as fabric stores. It works best on the stovetop, but it's easier to use in the washing machine in hot water. See "What chemicals can be used to remove dye?".

(Please help support this web site. Thank you.)