Mordanting with Alum Triformate

One of the joys of Aluminium Triformate is its simplicity, no heating required and no complicated setup. It's a true cold-process mordant that works beautifully on all natural fibres, cellulose and protein.

There are two ways to work with it, and both are wonderfully practical depending on how you like to dye.

Before You Begin — Safety First

Aluminium Triformate is one of the gentler mordants to work with, producing minimal odour and dissolving easily. That said, always wear a dust mask or respirator, gloves, and an apron when handling the powder, as it can irritate the nose, throat, and skin. Work in a well-ventilated space, keep your dye tools separate from your kitchen utensils, and supervise children closely.

When it comes to disposal, Aluminium Triformate can be safely poured down a household drain connected to a sewage system. Do not dispose of it directly into waterways or stormwater drains.

How Much to Use

Method 1 — Grams per Litre (gpL): Use 20g of Aluminium Triformate per litre of water in your mordant bucket. This is ideal if you want to keep a standing mordant bath that you can dip pieces into as needed and top up over time.

Method 2 — Weight of Fibre (WOF): Use 5–10% WOF. This is the method for careful record-keeping and consistent, repeatable results. A higher percentage will give you deeper, richer colour.

Method 1: The gpL Bucket Method

This is the low-fuss approach, perfect if you want to mordant a piece or two without a lot of weighing, calculating and timing. And it can be ready to go in the studio when hyou need.

1. Calculate how many litres your bucket or dye pot holds. Measure out 20g of Aluminium Triformate for every litre.

2. Remove about 500ml of water from the bucket and use it to dissolve the mordant powder in a smaller container, stirring until fully dissolved.

3. Pour the dissolved mordant back into the bucket and stir well. Mark the water level on the outside of the bucket with a piece of tape so you can track it over time.

4. Add your wetted-out fibre, and rotate occasionally for even coverage.

5. Leave for a minimum of four hours — overnight gives the best results. You can leave fibres in the bath for multiple days.

6. Remove, rinse well, and proceed to dyeing.

   
   

The bucket can be reused indefinitely. As the mordant strength lessens or the water level drops, simply top it up using the same 20gpL calculation.

Method 2: The WOF Method

This is the method for the careful, record-keeping dyer, great for achieving consistent results batch after batch.

1. Measure out Aluminium Triformate

2. Dissolve the Aluminium Triformate in a small amount of warm water, stirring until fully clear.

3. Fill your dye pot or a clean bucket with warm water from the tap.

4. Add the dissolved mordant and stir well.

5. Add your wetted-out fibre, stirring occasionally for even coverage.

6. Leave for a minimum of four hours. Overnight gives the best depth of colour.

7. Remove, rinse, and proceed to dyeing.

Storing Mordanted Fibre

You don't have to dye immediately after mordanting .

• Short term: Store mordanted fibre damp in a sealed plastic bag in the fridge for 3–5 days. This curing period can actually increase depth of colour — a lovely bonus.

• Longer term: Air dry mordanted fibre completely and store for future use. Label it clearly so you know it's ready to go when inspiration strikes.