When using the rust technique if you want the process to stop you need to neutralize it with a salt water solution. I put about 1/4 cup salt into a five gallon bucket, if that gives you a ratio.
I use straight vinegar and all sorts of rusty objects, I keep telling myself I will photograph those last 47 objects and get them onto the website but it doesn't seem to be happening.
You can do pole wrapping and bound resist techniques with this, also you can sprinkle iron mordant or iron shavings onto your fabric for other patterning. I suggest the iron mordant over the shavings, shavings often imply sharp things that can cut you, and they may be coated in machiners oil.
You can also do this technique using old copper pieces but it takes a bit longer.
If you like your rusty pieces and want to push it further rinse it, neutralize it, rinse it again and then rust the fabric once more. This will help prevent the fabric from rotting through.
Your natural rust is an iron oxide. Wear gloves and a mask when working with it, iron in that form loves to bind with your hemaglobin blocking all available sites for oxygen, ask me how I know. You can become gravely ill from too much contact with raw iron products. And it varies with each person.
Working with natural rust? What color is your natural rust? It comes in about 10 or more natural colors depending on what’s in the neighboring soils.
You can mix this natural rust with water or soy milk and paint your fabrics with it. I mix the rust with water, stir really well, let it sit for 24 hours then apply to the fabric, use a junk brush. Let the fabric dry/cure for 24 hours and then rinse. By letting your natural rust sit in the water for 24 hours your ensuring that all of the color will dissolve. I use about 1 TBS of oxide to 1 cup of water.