Instructions for dyeing fleece and wool in a microwave oven and on a stove top. Kenanthrol acid milling dyes are suitable dyes for fleece, wool, silk and other protein fibres. As the name implies these dyes require a hot acidic dye bath for the dye to bond with the fibre. These dyes can be used in a conventional way on a stove top or they can be used in the microwave oven. The colours are all intermixable so you will be able to mix the olours as you would in a paint box.

A word about safety

Although these dyes are amongst the safest on the market, It  is best to avoid inhaling the dry dye powder. Where possible use the dye in solution. If you are using the powder for any length of time it is wise to use a facemask, (available from most  DIY stores). Clean any spills as you go, to avoid unwanted stains. Protect yourself and the work surfaces and keep the dyes away from children, food and pets. Do not use dye utensils for food preparation.

Washing raw fleece prior to dyeing

Soak half a fleece at a time in a bath full of hot water with a large helping of detergent. Make sure you agitate the wool as little as possible as this will lead to felting. Drain off water and dirt after 45 minutes and rinse in hot clean water. Depending on how dirty the fleece is you may have to do this again. It is a good idea to add half a cup of vinegar to the final rinse if the fleece is very strong smelling. Place in a muslin bag or a pillow case and fast spin in the washing machine. If you don’t have access to a washing machine, roll up in a large towel and squeeze hard. Lay fleece out to dry.

Other wools and fibres.

You need to make sure they are thoroughly clean as this will affect the efficiency of the dye. I give most fibres a good soaking in detergent and a good rinse beforehand just to make sure any greasy coatings have been removed.

Dyeing with Kenanthrol acid dyes

 Quantitys of dye and fixative needed for 100g dry weight of fabric

Shades                                    Acid dye                                 Fixing agent  

Pale                                       0.1 – 0.2 grms                    ammonium sulphate or ¼ cup of white vinegar

Medium                               0.5 – 1 grms                        ammonium sulphate or ¼ cup of white vinegar

Strong                                   1.5 – 2 grms                        ammonium sulphate or ¼ cup of white vinegar

Black                                      3.0 – 4.0 grms                    ammonium sulphate or ¼ cup of white vinegar


Make sure the wool or fabric is clean You need to make sure your material is thoroughly clean as oils, sizing and other contaminants can affect the efficiency of the dye. I give most fibers a good soaking in detergent and a good rinse beforehand just to make sure any greasy coatings have been removed.

Method for dyeing  Kenanthrol Acid dye on the stove top for 100g of fibre

  1. Measure approx 3 liters of warm water per 100g of fibre into a heatable pan,   preferably stainless steel as other metals may affect the dye shade.   There should be enough water to allow the fibre to float freely.
  2. In hard water areas add 3gms Calgon – dissolve
  3. Disolve 6g of Fixing Agent (Ammonium Sulphate) or add 1/4 cup of white vinegar per 100g of  fabric
  4. Weigh out dye powder. In a separate dish add a little warm water, mix to a paste. Add boiling  water to dissolve. Add dissolved dye to dye bath
  5. Add damp fabric to the dye bath and stir gently with a wooden, plastic or stainless steel  implement.
  6. Raise temperature slowly to 95°C. Continue at this temperature for 20mins or (30mins for   strong shades).
  7. Remove from dye bath, rinse in tepid water. Finally wash with detergent and leave to dry.

Dyeing with kenanthrol Acid dyes in a microwave

This is suitable for smaller items

Items you will need -:

  1. Large microwave-able bowl.
  2. Measuring spoons
  3. Measuring jug
  4. Clear malt vinegar

Method for dyeing wool or fabric in the microwave

  1. Take about 100g – 150g of the washed raw fleece and soak in a washing bowl full of hot   water and detergent. Rinse through with clean water and squeeze dry by hand.
  1. In a small measuring jug, dissolve approx 1.5g of dye powder (about 1/3 of a teaspoon) in   about a tablespoon of warm water and mix to a paste. Add boiling water from a kettle and   fill to 200 ml
  1. Stir thoroughly until the dye has completely dissolved, then let the mixture cool to room  temperature.
  1. Put 1 liter of hot water in to a large microwave-able bowl. (I use one witch holds 3 liters).   Add the dye mixture, then sprinkle 3g, Approx 1/2 a teaspoon of ammonium sulphate in to  the solution
  1. Give the mixture a good stir so that the particles dissolve. Add two tablespoons of clear malt vinegar and then the wetted fleece.  (You may leave out the ammonium sulphate if   there is none available and use 150 ML of the malt vinegar instead)
  2. Place in the microwave and cook on full power for about 12 minutes
  1. Allow the fleece to stand in the mixture as it cools down.
  2. Rinse thoroughly so any loose dye particles are removed then leave to dry