Preparing an Indigo Vat

 Put about 20 L of hot water (110°-140° F) in a plastic pail ( we are using two smaller pails so do each pail with 10L of hot water). A water heater is handy if you need the vat for a long period of time. 

  

Make up two cups of very hot water with ¼ teaspoon of Soda Ash. Stir well. (This is our alkaline). Divide into two cups, one cup for one pail one for the second pail.

   

Indigo requires an alkaline environment of about PH 11 (PH 8 for protein fibres). Neutral PH is 7. If you don't get 11PH, add more soda ash in small amounts until you get it. We ended up need 3/4 tsp. If you add too much you need to add more hot water. 

   

Add ½ teaspoon of Thiourea Dioxide (removes the oxygen in the water) to each vat and stir.   Allow to “reduce” (de-oxygenate) for 15 minutes. 

Carefully lower the indigo stock solution into the vat being careful not to create bubbles that will introduce oxygen, pour ½ of the stock into each vat and stir. Allow to sit for about 30-60 minutes till ready to use.  

Be sure to wear gloves! 

Put your fabric in the indigo vat for 3-10 minutes per dip. The more you dip the darker the colour. 

Remove the fabric from the vat , careful not to create oxygen bubbles.

Oxidize for 20 minutes

Allow your fabric to oxidize for 24 hours before doing a mild vinegar rinse. Do 4tsp  of vinegar in 4L of water.  The vinegar rinse neutralizes the alkaline from the vat. 

 oxidize in the air for 24 hours then do a mild , about 4 tsps. Vinegar to 4 liters water. 

then just rinse and allow to dry.   

Instructions Credited to The Indigo Manual