5-gallon Copperas or Ferrous Sulfate Indigo Vat
Can be prepared the same day allowing 4-8 hours to fully reduce and then it’s ready to use!
INGREDIENTS:
• 50g Natural Indigo Dye Powder (www.maiwa.com)
• 100g Ferrous Sulfate
• 150g Calcium Hydroxide
• 5 Gallons of water
• 50g Citric Acid or a gallon of vinegar. Either can be used. (Either a spoonful of citric: acid, or a hearty splash of vinegar in a gallon of water to create a weakly acidic rinse to pH neutralize your dyed fabric after it comes out of the vat).
SUPPLIES:
• Kitchen Scale with .00 accuracy
• 5-gallon bucket with tight fitting lid
• Empty jar with tight fitting lid
• 20+ marbles or pebbles that will frt into your bottle
• Stirring stick
• Respirator
• Rubber gloves
PROCEDURE:
1. Start boiling about 4 gallons of water. The volume is not particularly important as we are making a condensed dye solution.
2. While the water is heating up, measure out the chemicals into separate containers. Be sure to wear gloves and a mask to protect your health.
3. When the water starts to boil, add it to your five-gallon bucket.
4. Carefully spoon about 1/3 of the indigo powder into a quart sized jar. Carefully add a handful of marbles or small stones. Add about 2 cups of tap water and place the lid securely. Shake vigorously. This will make the indigo suspension -hydrating the indigo making it more easily to react in solution.
5. Add t.he indigo suspension to the vat (be careful that the marbles do not enter the vat) I Rinse the jar with a little more water and add that to the vat.
6. Once all the indigo powder suspension is added to the vat, slowly add the ferrous sulfate.
7. Stir slowly with a dowel .i.n a circular motion so that you do not introduce air bubbles and continue adding the ferrous sulfate.
8. Sprinkle about 1 cup of calcium hydroxide onto the surface of the vat and stir In a slow circular motion until the powder is dissolved in the vat. Continue adding In this manner, adding a little at a time and check the pH after each addition. Stop when proper pH is reached. (pH 10-Wool, pH 11 Sifk, pH 12 Cotton)
9. Wait 10-15 minutes until a coppery film is seen on surface, vat color is greenish yellow. You will notice a reaction beginning to occur! The iron and lime will fall out of suspension, settling to the bottom of the vat and the indigo will react with the dissolved ingredients and as it becomes reduced (undergoing the molecular change to leuco-indigo} the vat will change color to a transparent yellow green color with a distinct coppery purple surface.
10. Top up your vat with hot water (splashing as little as possible} until it is a couple inches from the top. This will leave enough room to add items into the vat and not displace so much liquid that spillage occurs.
11. Stir the vat around in one direction creating a vortex which will blend all the ingredients. Cover the vat i,vhen you’re not actively stirring. Revisit your vat a few more times over the next hour and stir each time.
12. Your vat is now ready for dyeing! The indigo reduction reaction is ongoing, and the vat will continue to strengthen for another day at least. Remember to keep the lid on.
AFTER TREATMENT:
When using the Copperas or Ferrous Sulfate Vat, the iron needs to be neutralized after you have finished dyeing your materials. Your materials have been exposed to a vat with pH 11 or greater, In the long run, this can be detrimental to the pigment and the fabric. Thoroughly rinse your mterials in water, starting with cold, gently proceed to warm until no more pigment comes off the pleece. Next, in one gallon of water, add either 1 tablespoon of citric acid crystals or ! litre of whate vinegar. Stir well. Add the goods to be neutralized, and soak in the solution for about 20 mintes, This will reduce the pH and also help to brighten the blues of the piece if there is any excess iron that came Into contact with the fiber. Rinse well.
CARING FOR YOUR INDIGO FABRICS:
Wash your materials with a neutral detergent separately in a cold-water wash for the first wash. If mixed with other garments during th\s first wash, there is the possibility that they will crock off and transfer color through rubbing against other pieces. For future laundering, wash with dark colored fabrics in cold with a mild soap.