I thought I'd put down a few things about the actual tie dyeing process, some links and thoughts. I am a mere dabbler, but I enjoy the challenge of tie dyeing ~putting colours together, visualizing a pattern and bringing it to life, the surprise of*untying* to see what resulted!
Over the years I have tried tie dyeing many times, never with much success.
I will tell you~ throw away your RIT and Tintex and get yourself some Procion MX fiber reactive dye. It makes a world of difference.

When the fabric is properly cleaned and pretreated (soda ash to 'rough up' the fibers) these dyes bond chemically with the cotton (or other plant fibers) making them permanent. There are various chemicals that you can then use to aid or change your results (thickeners, urea for brilliance etc.). I have not yet experimented with the thickeners, though I would like to do so ~ but having to order all my chemicals and have them shipped from the US (+customs) is VERY expensive, so I am trying to keep it simple. Batching items for 12-24 hours yields brighter results, A proper post wash routine, including a dye suspension chemical (like synthrapol) helps rinse away non-reacted dye and set the final product.
You can learn so much more about it at these sites (for starters):
http://tie-dyewiki.com/wiki/tiki-index.php
http://www.pburch.net/dyeing/howtotiedye.shtml
I regularly read a little to get new ideas (many of my experiments don't get listed as I use whatever I can lay my hands on and save the good blanks for sales!).

Here are a few tips I can share:

• wear gloves! (and eye protection and a NIOSH mask when mixing dyes in powder form, they are dangerous if inhaled) and respect the chemicals.
• keep a clean work space. One small crystal of procion dye yields a LOT of colour if it escapes and gets wet! Nothing worse than a marred piece from an errant drop of dye. Wipe up constantly and keep lots of paper towel or shop towels handy.
• plan ahead. Know what you are going to dye and have the items prepped, and have a general idea of how and mix the appropriate dyes (plan several projects in the same colours to make the most of your dye)~ you will probably be happier with your results!
• Be prepared for surprises! Sometimes amazing results happen and other times, crazy mistakes, so be willing to accept what comes and learn from it. I love that in dyeing, as in life, you can be creative, and work hard and better your mistakes, often making something even more beautiful in the end~!
• Be prepared to say "No, that finger is not gangrenous!" "No, I didn't burn my arm, its fuchsia dye!" "No, my circulation is fine, and yes, I know my fingertips are blue!" your life will get a whole lot more colourful (or at least your skin!).

For me, dyeing, batching and painting an item for an order or for friends and family is a minimum four day process with all the reacting and curing that it takes. Working full time and chasing after a two year old can make that take a little longer, so I encourage my buyers to be patient if you place a custom order!

Tie dyeing is a lot of fun, but honestly I would save the procion dyes for grown-up dyeing and let the kids play with the safer stuff. Dylon is your best bet for safe but bright and long lasting colours for kids. And consider bleach pens to draw with after dyeing fir a neat effect.

L