Iron Water

If you want consistent, repeatable colors when modifying your natural dyeing with iron, iron water is not the thing to use. Move along and search online for a recipe to make an iron acetate mordant for anything that requires measurable results. However, if you want to introduce a little bit of chaos, surprise, and pure chemical magic into your practice, have I got the recipe for you.

Iron water is incredibly simple to make. The hardest part for me was sourcing rusty iron because it turns out you can’t buy that from your local hardware store and the streets of Dublin are suspiciously tidy and rusty-nail free on the one week when you’re trying to find them. However, Orlaith came through for me and supplied me with a lovely bag of rusty nails and metal pieces. (Get yourself a friend who doesn’t think it’s weird when you ask for rusty nails in bulk.)

Once you have your rusted iron, all you need to do is place that into a container and fill it the rest of the way up with 1 part vinegar to 3 parts water. Give it a quick stir and then leave it alone for 3-5 days or until it starts to look nice and rusty.

Obviously, because I am who I am, I did not leave my iron water alone for 3-5 days. Instead I worried over it like a new pet and photographed it every day, for science, before forgetting about it and leaving it alone while I went on a little vacation. I came home to find that it had done exactly what it was supposed to do without any intervention from me. Trust the process folks.

Day one. I added the rusty iron, vinegar, and water. Then I sat, watched, and waited. Nothing happens on day one. Do not bother to sit and wait for a cool visible change.
Day two. Looks suspiciously like day one, doesn’t it? The rust started to peel off the metal, but wasn’t mixing into the water.
Day three. OK! Things are starting to happen! The water got a distinct rusty, murky look to it on day three. This may be because I lost patience and opened the jar and gave everything a good stir? But in theory, you should be able to start using the iron water at this point.
Day four. Slightly more murky, and the last of the rust coating the bent metal peeled away into the water and started to disintegrate.
Day five. According to the recipe I was following, the iron water should definitely be usable at this point.
Day ten. Then I went away, didn’t use the iron water when I was supposed to (5 days), and came home to this absolutely gorgeous mix of rusty, orange liquid.
Day ten view from the top. Look at that gorgeous, crusty layer of rust that we have developed! At this point, I’ve named the iron water and am determined to keep it going as long as I have any interest in natural dyeing (sort of like my Covid sourdough starter. RIP).
Day 15. My dye samples have finally been properly wetted-out and mordanted and I’m ready to use this iron water! Cracking through that rusty, crusty top layer with my wooden spoon was incredibly satisfying.

The results of dyeing with my iron water (left) compared to iron acetate (right). Interestingly, the pitcher with my iron water was a lighter, more rusty brown shade but produced far darker, nearly black results on the textiles when they were wet. The iron acetate water turned nearly black, but gave more subtle, greyish-brown saddening results when the textiles were still wet. This led me to believe that the iron water I used was a much stronger concentration of iron than the iron acetate mixture where I was able to measure out exactly 2% iron. It would be a fun experiment to do this same test each day that the iron water is maturing and see if it gets stronger over time, or if it reaches a point and then stays roughly consistent. Although, with all the steps of mordanting and dyeing, this experiment is beyond my current space that I have available (both physical and brain).

After dyeing all of my samples and letting them dry, I organized them into my portfolio. Now that everything is dry, it’s interesting to note that the differences between the iron water and the iron acetate are less clear cut. The iron water samples lightened several shades while they dried, while the iron acetate samples darkened over time. The iron water samples that, when wet, had looked like black textiles turned into dark browns and dark greens.

The answer is not just ‘my iron water was stronger’. The iron water did produce darker shades on some of the silk and wool samples. But, on the cellulose samples, the iron water gave warmer, rustier tones that fit in more harmoniously with the rainbow of natural dye colours I am discovering. The iron acetate has a greyish undertone in nearly all of the samples. The difference is subtle, but it’s there.

The iron acetate is easier to use if you’re wanting a measurable result. I knew I had a 2% mixture of iron acetate, and I know I can create that same mixture over and over and always get the same grey tones. However, the natural, earthy, rusty tones that came from the iron water are appealing enough that I know I’ll be letting a little more chaos magic into my dyeing in the future.

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