Making a Long Term Vat

Q: I would like to have a large, permanent, natural indigo vat that I can upkeep and maintain. I’ve been buying kits but I don’t want to keep creating so much waste emptying and starting fresh every time the vat is exhausted. Do you have any input about what kind of vat is best? Or any pointers? I haven’t used your kit yet, but I am thinking of getting one - is it possible to use that as my base?

A: I’d recommend the ferrous vat (what’s in my kit and on my website) for a longer term vat. It is easy to maintain. Just make sure you AVOID THE SEDIMENT which will build up at the bottom of the vat over time as you sharpen it to maintain it. I’ve made Frankenstein’s monster style vats in the past (part fructose, part iron, part thiox). You can kind of just blend them together at will! The vat from my kit could certainly act as a starter. You’ll just have to dispose when you build up too much sediment to be able to dye what you want to dye cleanly and easily. If you’re going big, I recommend sourcing a steel 55 gallon drum. Though the investment in indigo and ingredients is much more in the beginning, they are actually much easier to use and maintain at that scale than a little 5 gallon guy.

Indigo Resist Screen Printing

Q: I have some questions about indigo resist screen printing. What type of screen do you use? What density? And what types of resist are you using? I’ve seen the rice paste recipe on your website. Do you ever screen print with other resists like mud or flour/water?

A: For indigo resist screen printing I use a 40 mesh screen, create my designs with cut vinyl (make sure you get the stickiest kind) which I place on the bottom of the screen (the print side not the ink side) and print with a traditional Japanese rice paste recipe. You can use photo-emulsion for preparing the screen but I find that it tends to get pixelated when using 40 mesh, which is why I create my designs using adhesive vinyl. You can still get incredibly crisp lines and points when working with a very open mesh.

I've tried a couple mud recipes and found the rice paste to hold up much better over repeated dips. I've never tried wheat flour/water, just the rice flour/water. Just make sure to sieve your dry ingredients through a 60+ mesh screen to ensure that they all properly fit through a 40 mesh screen when you're printing. I've found that it is hard to find rice bran that is milled fine enough.

Rinsing in Still Versus Running Water

Q: I have a question about rinsing my pieces after dyeing. Does it have to be done in running water or can it be done in multiple buckets?

A: The rinsing can be done in dingy water up until the moment the piece is going to be opened. At that point, use fresh water (or at least the cleanest rinse water bucket you have). Dirty rinse water can stain the pristine white resisted portions of the fabric. The staining is not permanent but it is difficult to remove and will naturally fade out over time (though in patchy ways and will turn yellow before disappearing).

Rice Paste Resist Longevity

Q: I have a question about your rice paste recipe. Do I need to use it immediately after I make it or can I store it in the refrigerator in a jar? And if I can store it, do I use it straight out of the fridge or do I need to heat it up?

A: I've used the paste successfully after refrigerating for up to two weeks. After that, it just tends to be less "sticky" and will ferment. I've actually used some that got moldy in the fridge and smelled fermented. I just scraped off the mold and used it. Worked great! I've anecdotally heard that it can be frozen for longer periods of time and thawed before use but I’ve never tried that.

You can use it cold straight out of the refrigerator, though the consistency seems to be more workable when it gets back up to room temperature.

The best results definitely come from fresh made paste that has been allowed to cool to room temperature.

Destabilized AKA De-Fatted Bran in Rice Paste Resist

Q: Your recipe for making rice paste resist calls for de-fatted bran. Is that the same as stabilized bran?

A: I have seen the two terms used interchangeably. All the bran does is add fluff which makes the paste spreadable. The sweet rice flower adds the sticky.

Dyeing Over Multiple Days

Q: I have done several dips on a piece that I have shibori tied. I would like to do more dips, but need to stop for the day. Can I stop mid-process on a piece, let it dry, and come back to it tomorrow or in a week?

A: Yes, no problem. Just be sure to rinse your piece VERY well before it dries and fully re-hydrate it before the next round of dyeing.

Indigo Flower Comes and Goes

Q: I made a ferrous vat using your 1-2-3 instructions. I had a proper indigo flower upon completing the vat. But when I opened my vat this morning to use it the flower was gone except for just a few bubbles. Does this indicate a problem?

A: No problem! The flower should reform after proper stirring.

Dipping Metal in my Vat

Q: I have come across some pieces of scrap metal that I would like to try to wrap my fabric around to see what kinds of patterns it might make when dipped in my indigo vat.  Will the metal affect my vat?  What if the metal has rust on it?

A: The metal will not affect the vat.  If the metal has rust on it, the rust may transfer onto the fabric and make orange/brown stains.  These stains can be removed with a simmer in citric acid.

Using Pencil to Make Marks on Fabric - Does Graphite Affect the Vat?

Q: I am interested in using some stitched techniques to create patterns on my pieces.  Everything I read tells me to use tailor's chalk or a disappearing water soluble fabric marker to plan out designs on my pieces, but I have been using pencil.  Will the lead from my pencil affect my vat?

A: Graphite will not harm your vat but it is very challenging to remove from fabric so chalk is definitely better.

Under-Reduced Fructose Vat

Q: I have been dyeing in a fructose vat and no matter how many times I rinse my pieces the water still runs blue. Am I doing something wrong?

A: My guess is that the indigo in your vat isn’t fully reduced. Fructose vats are often “under-reduced” which means that the color is more weakly adhered to the fabric and thus rinses out more. You can just add new reducing ingredients to your old vat contents so you don’t waste the indigo though you’ll begin to build up more sediment which makes the dyeing more challenging (as you’ll need to make sure your fabric doesn’t get that material on it).

Troubleshooting a Different Vat Recipe

Q: Yesterday I tried an indigo iron vat recipe that was almost identical to yours, except it called for less of each ingredient (20g indigo, 40g ferrous sulphate, 60g lime) and it suggested starting with all of the water (nearly boiling) rather than 1 gallon and then topping it off. I used Stony Creek indigo 40%. After an hour it had the bronzy oily surface and the bubbles in the middle, so I thought it was good to go. However, it just stained the fabric a dull grey/blue rather than the characteristic green-to-blue change upon oxidation. Do you think it was because I didn't use enough ingredients? Or didn't let it sit long enough? Also, it was way too hot to submerge my hands into, is it ok to let it cool a few hours before dyeing?

A: My suggestion is to wait longer before dyeing. If it turns gray, you were most likely dyeing in the ‘unsettled’ sediment OR the indigo was not properly reduced yet. Allow the ingredients to settle out and the temperature to get cooler before you start dyeing.

Starting with all of the water boiling rather than heating only 1 gallon for mixing and then topping off after will not make a difference or lead to the challenges you are describing. You can even make your vat in completely cold water, it just effects the amount of time it will take for the indigo to properly reduce. When using hot water, proper reduction can happen in as little as one hour. When using cold water, proper reduction takes approximately 24 hours.

The ratio of ingredients is right on but those numbers seem low to be able to power a 5 gallon vat and that could also contribute to your difficulties. Don’t be afraid to add more iron and lime to get that indigo activated.

The vat will remain viable for quite a while after it is mixed up, days to weeks, depending on how well behaved you are with your fabric in the vat.

Avoiding Sediment

Q: I made a 5 gallon iron vat following the instructions on your website and I am trying to dye some cotton gauze scarves. The first one came out well but the rest have come out a grey/green - any thoughts on what I might be doing wrong? I am wondering if I am coming into contact with the sediment at the bottom of the vat? The only other time I dyed I was dipping in a 55 gallon drum so I didn’t have to worry much about the sediment and I am wondering if now that I’m using a smaller vat if my pieces are dragging in the sediment. Is there a way to protect against that?

A: Yes, it does sound like sediment is the issue. The ferrous vat has an iron-rich sediment, which when coming into contact with the fabric will stain it yellowish - and when that is layered with the indigo, a sludgy green. My suggestions would be to switch to a bigger/deeper container and avoid the sediment altogether or put some sort of bag/basket/strainer in the vat secured to the top of the container so that the pieces literally cannot touch the sediment. Also, make sure to not stir the vat beforehand on the same day it is used to dye. The sediment needs time to settle.

If you are dyeing in a steel pot, I recommend heating the contents up to about 120 and holding for an hour or so, stirring occasionally. This will revitalize the vat. Otherwise, you can reheat the contents with some sort of heating element or bucket wrap like this: https://www.amazon.com/dp/B00OYEABGQ/ref=biss_dp_t_asn

It may seem "expensive" but its amazing how much better a warm vat performs!

Indigo Vat Troubleshooting: Recipe Quantities for a Large Vat

Q: I am wondering if you are able to help me troubleshoot my vat. I made a 19 gallon iron vat in a plastic bin about a week ago with no success. I found instructions online that called for 20g indigo, 40g iron, and 60g lime for a 5 gallon vat, so I multiplied it by 4 for 19 gallons (80g indigo, 160g iron, and 240g lime). I see that this recipe has lower quantities of each than what you recommend and I am not sure why or if this is the issue. Initially the vat seemed to work. On the first day it had a coppery sheen but no flower and produced mid-dark blues. I dyed approximately 100g of fabric. On subsequent days, however, everything went downhill. I have continuously checked the pH, stirred, and added more iron and lime when I thought necessary. The vat liquid continues to be blue but I cannot get any good color when I dip. I tried restarting it by adding 1-2-3 solution again (as per your instructions). I am pretty sure the vat is not exhausted, but this still has not helped. I bought iron sulphate from a garden shop, it is ferrous (II) sulphate as far as I am aware. I am thinking of chucking out the vat and starting again by scaling up your recipe of 50g, 100g, 150g. Any thoughts?

A: No need to chuck! I'm going to assume that you actually have the right kind of iron, but definitely double check! It just sounds like your numbers are low for the vessel. I'd use at least 600g lime, 400g iron to properly reduce that amount of liquid (maybe more). If you've still got the vat, try decanting a gallon or two, heating to simmer, cut the heat then mix in another 450g lime and 300g iron (plus any additional indigo you may want). After ageing that for an hour or so (it will probably be a thick paste), add back to the large vat and stir thoroughly. It should dye well on the following day.

Sharpening Your Vat

Q: I'm wondering if you can keep an indigo and iron vat going by feeding it more after it’s exhausted of indigo or do you have to begin again from scratch once there's no indigo pigment left in it?

A: Yes, you can keep the vat rolling by "sharpening" it. Over time (after a couple rounds of sharpening) you will build up a bunch of sediment that will start to cling to the bottom of your fabrics and leave some "muddy" indigo tones. At this point, you do need to start from scratch, or just decant the clear liquid and discard the sediment, then top it up.

So, try adding all ingredients again in proportion. I decant some of the clear liquor (1-2 gallons) from the top of the vat into a stainless steel sauce pot that I've dedicated to dye use, heat to boiling, then remove from the heat and add the ingredients. Mix well (immersion blender without making bubbles if you've got one). Let that sit for a few hours until it is an insane neon yellow, then add back into the larger container.

Top up your vat with fresh, hot water to keep it near the brim.

You can then let it cool to ambient temperature and use as normal.

Stirring Your Vat

Q: Should I stir my ferrous vat every time before I use it?

A: I recommend letting your vat settle out at least an hour before dipping after the last time you’ve stirred. Stir when you finish a dye session. If you stir too close in time prior to dipping, the sediment will won’t have time to settle and you’ll get sediment on your piece, which is not ideal as it can tint your piece toward a ‘muddier’ indigo tone, but it can be rinsed off.

You can reference “Q: I am dyeing in a ferrous vat and got sediment from the bottom of the vat on my piece. Is that bad? What should I do?” to learn more about how sediment affects your piece and what you can do about it!

Also, when I stir it is usually for only 20-30 seconds and is only to get all the sediment up and moving around. There is no benefit to prolonged stirring, or stirring your vat when you aren’t preparing to dye in it, and in fact that is a great way to introduce oxygen into the vat which will weaken it.

Adding More Pigment to a Fresh Leaf Extraction Vat

Q: I made an indigo vat using fresh leaves. I used washing soda for pH and sodium hydrosulphite for reduction. The vat worked very well but the dye is all taken up now. Can I add more leaves to the vat to give it more pigment or must I start over with a new vat?

A: I’ve never added fresh leaves to an existing indigo vat, and can’t imagine that it would be a good way to go, what with the sediment, elevated pH and the dye already in the liquid. You can definitely extract the pigment from the leaves separately and add the extract to the vat though with additional pH adjusting and reducing agents to strengthen the existing vat.

Making a Vat for Pale Dyeing

Q: I am about to make a 5 gallon vat and I only want to use it to dye some pieces to a pale blue. Since I’m only wanting a pale color, can I reduce the amount of indigo paste I add to the vat so I don’t waste indigo? If so, how much indigo paste would you recommend using?

A: For pale blues, I'd recommend starting at 10g of indigo extract for a 5 gallon bucket, but still use 100g iron and 150g lime. This will make sure that the indigo is fully reduced and will add incremental pale shades to your pieces. You can paste up and add more indigo as that vat loses efficacy.

Sizing Up Your Vat

Q: I have never done an indigo vat in anything larger than a 5 gallon bucket. However, I was wondering about using a large trash can (32 gallons) for yardage. What are your thoughts? I was planning on doing a cold vat with iron and lime and have had great results in the 5 gallon. Do the proportions simply need to be multiplied by 6 to account for the size? Ex. if I used 50 grams of indigo in a 5 gallon vat, I would use 300 grams in a large vat. That just seems like so much indigo!

A: Yes, you can just increase the scale accordingly. It is quite a bit of indigo, but the vessel is very large! I work out of a 55 gallon vat right now and initially used a couple pounds of indigo to set it up. Make sure that you get a very heavy duty trash can, as they tend to warp and bend and are challenging to work with when full of water!

Indigo Vat Troubleshooting: Lye and Hydrosulfite

Q: I am using a Philippine indigo paste and the instructions say to melt 100 g of the paste in 10 litres of hot water and then add 1.25g / liter of sodium hydrosulfite and mix until incorporated and then add 1.25g / liter of sodium hydrosulfite and let sit for 20 minutes before dipping.

I followed these instructions but my vat does not seem to be working well. It is very liquidy and weird and a pale blue. Do you have any suggestions for fixing this vat?

A: As an initial matter I would check to see how new your stock of Lye and Hydrosulfite are as they can become less effective if they're aged and oxidized.

I'd guess by your description that your vat was under-reduced (the liquid being blue and dull) which means I'd recommend adding more of the NaOH and Hydrosulfite. I usually add those together into a cup full of simmered water until they are completely dissolved, then incorporate that into the vat, stir the whole thing and check back in half an hour to see where you're at.

Dyeing Protein Fibers in a Natural Indigo Vat

Q: I’ve heard I cannot dye protein fibers like wool or silk in an iron vat, is that true?

A: You CAN use the iron vat for protein fibers, but when I do, I make sure that I do two things:

First, I make sure that the fibers NEVER touch the sediment at the bottom of the vat. The sediment contains a lot of iron which will bond to the protein fiber and cause the indigo to look dull and flat.

Second, I make sure that I rinse my pieces in acidic liquids immediately following each dip. Water with a little citric acid powder (half teaspoon per gallon) or a quarter cup of vinegar for about 4 gallons of water, works well. Ferrous vats have a high pH and animal fibers prefer a low pH. The high pH of the vat will break the protein chain and the fibers will feel scratchy or lose their luster if they are allowed to dry after coming out of the vat without being rinsed in an acidic bath first. I also soak protein fiber pieces in a mild vinegar solution overnight after dyeing and prior to washing. I’ve also heard, though never done this myself, that a little hide glue added to the vat will help keep the fibers in good shape.

If dyed properly, a ferrous vat will create beautiful blues on protein fibers. The ideal vat style for protein fibers is the traditional fermentation vat which is fed by decomposing plant matter, wheat bran and oxygen (from stirring) but is very challenging to execute on your own without guidance or experience. You can also look into a fructose vat or thiox vat for other options. Maiwa has a great PDF on different vat recipes here: https://naturaldyes.ca/indigo-pdf.