Treat Fabric with Alum Before Marbling
We'll marble 100% cottons. Fabric that's sold for dyeing is a perfect choice, but any cotton fabric will do. Pre-wash fabrics, and if they're "regular" cottons off the bolt, throw a few tablespoons of Boraxo into the wash to help remove coatings.
Treat Fabric with Alum
- Mix 3 Tbsp. of alum per quart of hot water. Make enough solution to cover your fabrics.
- Stir thoroughly to dissolve the crystals. Allow the solution to cool.
- Pour the alum solution in a bucket and add fabrics. Wearing gloves, swish fabric to make sure it is saturated. Allow to soak for up to 20 minutes.
- Wearing gloves, wring fabric pieces to remove as much alum as possible. Dry in dryer.
- Iron pieces and cut to size for your marbling tray.
Alum Cautions
Alum is corrosive and will destroy cloth if not washed out soon. Marble fabric as quickly as possible after treatment. I use fabric within 1-2 days.You'll rinse fabrics and heat set paints as you work, but until they are washed, fabrics contain traces of alum. If you heat-set the paints on your ironing board, some of the alum will transfer to the cover and will eventually destroy it. More importantly, if not washed out, traces of alum could be transferred to other fabrics ironed on the same board.
Set up a temporary ironing board or protect the regular board cover. Hospital pads with a absorbent tops and waterproof bottoms work real well -- no moisture passes through and you can throw the pad into the washing machine after each session.
