01/10/19 Product note: Our supplier is backordered on aluminum potassium sulfate, which is the normal mordant that we carry. We are substituting aluminum sulfate, which is the same active ingredient with a different refining process, resulting in more irregular-shaped granules that produce near identical results. We expect to have our regular grade of alum back in stock by the second week of November.
This is the mordant to use for protein fibers such as silk and wool, and is the traditional mordant used worldwide since antiquity. Alum is refined from bauxite and is a transparent crystal, resembling salt. We supply a food grade alum that is free of iron and other impurities.
You can use between 10-20% alum on the weight of fiber. 250 grams will mordant about 2500 grams (5.5 lbs) at 10%
Check out our How To Mordant instructions for detailed information on preparing your fibers for natural dyeing.