[quote=Prism99]Anyone using dye powders needs to be extremely careful with them. You do not want to expose children to the powders at all; they are toxic if breathed in, if carried to the mouth, etc. They are safer for children to handle after they are mixed with water. In classes, even as adults, we were always required to wear masks and gloves when handling dye powders and we were very careful to avoid spills.
When we teach the hand dyeing workshops to adults, we never have them mix the dye for two reasons, the safety factor (see above) and also the mess factor. What we do is mix all the dye up before hand and put all the dye in soda bottles, marked with the color in the bottle. You really only need a pink/red, yellow and blue. This will create all colors by mixing. The dyes should be mixed wearing a mask.
The soda ash can be purchased at a pool supply store if you can't find it anywhere else. I buy mine in 50# bags but you probably only need a small amount so hopefully Walmart or Joanne's will have that, too. This can also be mixed before hand if you want and put into gallon milk jugs.
If we run out during the workshop, one of the teachers goes to the backroom alone and mixes more dye. It isn't so toxic that everyone has to stay a great distance but this really helps with the controlled mess.
Be sure to have a lot of rubber gloves on hand. I suggest a pair per child. Don't try to use the surgical gloves, they break. The yellow ones at Walmart are fine. They are inexpensive or ask each child to bring a pair.
Good luck with your adventure and if you have more questions, please ask.
Barb