Why Steam?
  • I am thinking about painting wool yarn with acid dyes. Something confuses me about steam setting--why use steam heat as opposed to dry heat. A lot of people wrap their yarn or roving in plastic to steam--which means it isn't in contact with the actual steam. Others use paper, but I'm not sure the point is for it to absorb water. Why steam and not just dry heat around an enclosed container with the wetted fiber providing the moisture?

    Oh, and by the way, I saw a commercial for a new type of disposable steamer bags by Gladd or some other plastic company. I wonder if they'd work in the microwave for dyeing?
    L
  • Dear Empathy, Whenever dyes are fixed on natural fabric (this does not include disperse dyes on polester) some moisture is essential. With reactive dyes there is a chemical bond formed. Moisture plays a critical role. If no moisture is present then the reaction stops. That is why in tie dye the fabric is bagged in plastic for 12 to 24 hours. When printed the dry reactive dye is activated by heat, but heat alone won't do it. There must be moisture.
    Acid dyes do not react with the protein fiber, or polyamide, as in the case of nylon, but rather, in the presence of heat and moisture they migrate into the fiber itself. The dye molecules not only migrate, they also, somehow reorient themselves and that is what blooms the color.
    There are many fixing methods out there. They will all work so long as there is moisture one way or another. You don't need an actual steamer as long as there is water in the system when the heat is generated. A microwave actually acts on the water molecules pressent in the wet fiber heating them up. Fixation then occurs.
  • Wow, MKatz -

    Thanks for a very lucid explanation of a very complicated process. I can never comprhend chemistry and such, and I understood it very well!