The 5 minute Indigo Dye Vat - indigo vat dyeing as quick as it comes!
ten 100g skeins of BFL wool dyed with 10 grams of indigo crystals
- 10 grams indigo dye crystals
- 15 grams soda ash
- 15 grams Spectralite (thiourea dioxide or thiox)
- 5 litres water at 50°C
- 1 kg fibre (yarns, fabric, etc)
- 10 litre stainless steel saucepan or stockpot
- electronic balance or scales
Follow the usual precautions of wearing rubber gloves, and a face mask when handling chemicals. Keep the saucepans, jugs, spoons or any other utensils just for dyeing and do not use them for food preparation. It is better to weigh the indigo dye crystals, soda ash and Spectralite in labelled jam jars rather than on the bowl of the balance or scales. The jam jars can be used again and again. Make sure your Spectralite is not too old.
1. Soak the fibre overnight or for at least two hours. This opens up the fibres, increasing dye penetration. It also removes as much oxygen as possible and helps to prevent the fibre floating to the top of indigo dye vat. Just before you start to weigh the ingredients, warm up the fibre by putting it in a washing up bowl with warm water at about 50°C.
Indigo crystals are currently out of stock & we are looking for a new supplier
2. Place a jam jar marked ‘soda ash’ on the scales, zero the scales and weigh the soda ash in the jam jar. Pour 300 ml of warm water (50°C) in a Pyrex jug. Add soda ash to water, stirring well to dissolve it.
3. Place another jam jar marked ‘indigo crystals’ on the scales, then zero the scales and weigh the indigo. Add the indigo crystals to the jug with the soda ash solution, stirring slowly. The solution is blue at this stage and there is an oily film with a metallic sheen on the top. There should be a slightly sweet smell.
4. Weigh the Spectralite, add it to the jug and mix it gently. The colour of the solution becomes greenish blue and the oily film is still there.
5. Fill a stainless steel saucepan or stock pot three quarters full with water at 50°C. Keep the temperature at 50°C all the time.
6. Lower the indigo dye solution into the water, tilting the jug so that water enters the jug and the contents then flow smoothly into the saucepan. Do not pour from the jug whilst it is held above the saucepan.
7. The indigo vat should be ready in about 5 minutes. The solution should be a yellow-green colour with a bronze bloom on top. The indigo vat smells a bit like cooked kidney beans. If the solution is not yellowish green sprinkle a bit more spectralite on the vat, check the temperature and wait for 10 minutes.
8. Wearing rubber gloves, squeeze the fibre while still in the soak water, keep it squeezed (compression helps to keep the air out) as you let the excess drip over the soak water. Lower the fibre into the dye vat and then release. Leave the fibre in the vat for 5 minutes.
9. Remove the fibre which is yellowish green at this stage. Expose the fibre to the air, it will slowly turn from yellow to blue. Let the fibre oxidize in the air for 15 minutes. Rinse. If you want a darker shade of blue, dip the fibre in the indigo vat again for 1 min and expose for 15 min. Repeat a few times if you want. Leave to air overnight. Rinse well.
10. Immerse the fibre for 10 minutes in water with a little bit of white vinegar (about 2 tablespoons of vinegar in 4 litres of water) added to counteract the alkalinity of the indigo vat. Rinse well again.
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