Name: abbey

Message: ok im sorry if you have already answered this question but i looked and couldnt find it. so my question is after you are done tie dying should you put it in a plastic bag or just leave it sit on wax paper outside until it drys?  and how long do you think you should leave your shirts out to dry?

Fiber reactive dyes must have moisture present in order to react. If you are using Procion MX dye, there are two good ways to keep the dye moist on the fabric long enough to react thoroughly. You can use either one or both of these methods. You should give your dyes plenty of time to react with the fiber, in the presence of soda ash (from the presoak); I prefer to leave shirts at least overnight in a warm place (70°F or higher), so that all of the dye has reacted, which means that there will be no problems with backstaining of dye from one part of the fabric to another, during the washing-out step.

(Please note that none of this information applies to all-purpose dyes, such as Rit. Urea will not help Rit dye at all. It is for good fiber reactive dyes, such as Procion MX dye, which are necessary for the best tie-dyeing.)

The first and simplest method for keeping your dyes moist is simply to mix urea in with your dye mixtures. (See What is urea for? Is it necessary?.) Urea is optional in tie-dyeing, but it can be very useful, with fiber reactive dyes. It is a humectant, which means that it attracts water to it. If you use urea in your dye mixtures, then you can leave your dyed garments out overnight, without any covering, and they will stay moist enough for the dye reaction to continue, even if they seem almost dry to the touch. The amount of urea to use is one tablespoon per cup of water. This is equivalent to 15 ml, or 12.5 grams, for every 250 ml of water, to which you then add your dyes. I generally mix up one-quarter cup of urea, which is four tablespoons, in one quart (or one liter) of water, and then measure out one cup of this mixture to add dye to. 

The second possibility is to wrap your shirts in a waterproof covering, such as Saran Wrap or plastic bags, in order to prevent any water from evaporating. If you do this, you don't have to add urea to your dyes. If you use urea, you don't have to wrap your dyed stuff in plastic. You must do one of these, either urea or plastic; it is okay, but not necessary, to do both.

There is no drawback to using urea, as long as you have it. It is not expensive, and it dissolves in water with the greatest of ease. Urea is not toxic (it's a common ingredient in hand lotions and other moisturizers). It will stay good for a long time when stored in plastic jars, usually for years, but it can eventually go bad. If your urea smells strongly of ammonia when you open the container, then it has started to go bad and should be discarded (or used as fertilizer or to melt ice on your sidewalk in the winter). Ammonia changes the pH, so you do not want to use ammonia in your dye mixtures.

You can buy urea from your dye supplier. Order it from Blick, Grateful Dyes, PRO Chemical & Dye, Dharma Trading Company, or wherever you normally order your dyes from. You can also find fertilizer-grade urea in a feed store, but you should buy that only if it looks clean and white. You don't want the mess of dirty urea.

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