Back to Mordants and Additives
Soda ash
$4.40 – $8.00
Used with fibre reactive dyes as a colour FIXATIVE. Soda ash raises the pH and allows the dye to bond with the fibre. Generally used only with cellulose (plant) fibres such as cotton or flax. Also known as washing soda or sal soda, though this is a more pure form that the washing soda sold in supermarkets.
Also sometimes used in natural dyeing to create more alkaline conditions, and thus altering the colour with certain plants. Extensively used for indigo vat dyeing.
TO USE: Follow dye manufacturer’s directions for amounts and timing.
Dispose of spent dyebath in the usual way, most likely down the drain.
CAUTION: Wear a mask when handling powders. Wear gloves, can be a skin irritant.
Related products
Aluminum acetate
May 26/22 - back in stock, finally!
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
NOT THE SAME AS ALUM!! Aluminum acetate is used as a one-step mordant on cellulose (plant) fibres such as cotton, linen and well worth experimenting with on rayon fibres (including Tencel), bamboo, ramie, hemp and others. This is a more expensive but faster means to get natural dyes to stick without the more traditional alum/tannic acid premordanting method.
TO USE: weigh dry fibre and scour if needed (especially cotton). Calculate mordant required for 5% WOF (weight of fibre). Weigh and dissolve in hot water. Fill pot with sufficient water for the fibre to move, add mordant and stir. Enter fibre. Bring to 190-200°F and hold 1 hour. Stir yarns frequently. Cool overnight, then wash well. Dye immediately or dry for later.
Spent mordant solution may be safely disposed of down the drain (except for septic systems). It also may be diluted and poured on the ground, for instance on a gravel driveway or path.
CAUTION: wear a mask when handling powders. Wear gloves when handling powder or solutions, particularly when rinsing or handling wet yarns. Best done outdoors or with very good ventilation.
Tannin Blend
This is a blend of NATURALLY-SOURCED Tannin, usually from Quebracho and Sumac, possibly others. It will leave your plant fibres or fabrics a soft red-brown base colour before using other dyes.
Used mainly on as a MORDANT on cellulose fibres such as cotton, usually in combination with Alum.
TO USE: weigh dry fibre. Calculate mordant required at 15 to 20%% WOF (weight of fibre) each of Tannic Acid and Alum. Weigh mordants and dissolve in hot water in separate plastic or non-reactive containers. Add wetted fibre to Alum solution and soak for 12 to 24 hours. Rinse and place in Tannic Acid solution for 12 to 24 hours. Rinse again and place back in Alum solution for 12 to 24 hours. Wash and rinse well, then dye or dry for later use.
Spent mordant solution may be safely disposed of down the drain (except for septic systems). It also may be poured around garden plants that prefer acidic soil conditions.
CAUTION: wear a mask when handling powders. Wear gloves when using tannins, particularly when rinsing or handling wet yarns as they can cause skin irritation and staining.
Iron sulphate
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Iron darkens or "saddens" colours. It takes only a tiny amount to do this, and one must be careful with iron: too much will harshen or damage fibres. If you use iron with any regularity, consider having a dedicated pot for this purpose, as it sticks to pot surfaces and will affect the colour of future dyebaths. A chipped enamal pot is perfect.
Used mainly on protein fibres such as wool, alpaca, silk. Although it can be used as a premordant, most natural dyers use iron to alter the colour at the end of the dyeing process. If you prefer to premordant, follow the usual steps using iron at 6% WOF.
TO USE: Weigh fibre before wetting. Dye in the bath of your choice, with or without an alum premordant. Calculate iron mordant required for 2% WOF (weight of fibre). Dissolve iron in hot water. Remove fibre from warm dyepot, stir in dissolved iron and re-enter fibre. Simmer for 5 minutes, cool then wash and rinse well.
Spent mordant solution may be safely disposed of by pouring in the garden. Iron sulphate is a common soil amendment in agriculture and horticulture.
CAUTION: wear a mask when handling powders. Wear gloves when using iron, as it stains skin easily. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.
Tin Mordant
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Tin (Stannous chloride) brightens colours and really makes them "pop". However, it is one of the trickier mordants to use, and rather expensive. Some dyers prefer to premordant with tin, while many simply add "a pinch" at the end of the dye process, and heat the fibre for another fifteen minutes or so, cool and then rinse as usual. The amount recommended for this is only 25% of the usual premordanting amounts, below.
Used mainly on protein fibres such as wool, alpaca, silk. Tin can make fibre feel harsh and brittle, so do not exceed the recommended amounts. Yarns can also easily scorch during tin premordanting. Do not pack the pot too full of fibre! An upturned rack, marbles or stones can help keep yarns off the bottom of your pot.
TO USE: Weigh fibre. Calculate mordant required for .5 to 2% WOF (weight of fibre). Weigh tin and dissolve in hot water. Fill pot with sufficient water for the fibre to move, add tin and stir. Enter fibre. Bring to 180-200°F and hold 1 hour. Stir yarns frequently. Cool, remove fibre and wash well. Dye immediately or dry for later. Some dyers add cream of tartar at 5-10% WOF with tin.
Spent mordant solution may be safely disposed of by pouring in a gravel driveway or path.
CAUTION: wear a mask when handling powders. Wear gloves when using tin, as it can be absorbed by the skin. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.