Category Archives: dye auxiliaries

Can I use soda ash in my front loader washer to soften my hard water?

Name: Mary
Country or region: United States

Message: Hello: I am wondering if I can use soda ash in my front loader washer to soften my hard water. I am a beginner dyer and had to purchase some soda ash and wondered if I can use the same product for dyeing and as a water softener.

I have also seen washing soda (by Arm & Hammer) used as a water softener. Is that better? If possible, I’d like to use one product for dyeing and water softening. Please advise. Your comments/suggestions would be most appreciated. Mary

Soda ash is not a good water softener for dyeing.

What works really well as a water softener for dyeing is sodium hexametaphosphate (also known as Metaphos, and formerly sold under the name of Calgon). Here in the US, I recommend that you order Water Softener from Dharma Trading Company, or Water Softener from Colorado Wholesale Dye (they have really good prices!), or Metaphos from PRO Chemical & Dye, or buy Jacquard Products brand Calgon from an art supply store that sells dyes from Jacquard Products. (See Sources for Dyeing Supplies Around the World for contact information for these and other suppliers.) Do NOT buy Calgon that is not specifically labeled as being Jacquard brand or sodium hexametahosphate; although “calgon” used to mean sodium hexametaphosphate, the Calgon company now sells entirely different products, such as sodium citrate or polycarboxylate, under the same name, which can cause real problems in dyeing. As long as you buy a product with “hexametaphosphate” in the fine print, you’ll be fine.

Water softening is the removal of hard water metal ions, specifically calcium and magnesium. Calcium forms complexes with some unattached dye molecules that are difficult to wash out, which results in some slowly-released unattached dye that bleeds in the laundry; it can also produce unwanted spotting as the dyes attach to the fabric. Sodium hexametaphosphate binds to the calcium and magnesium, making them water soluble, and removing the problems caused for dyeing by hard water.

We frequently use sodium carbonate to increase the pH so that cellulose can react with fiber reactive dyes. Although sodium carbonate is listed as a water softener for some purposes, using sodium carbonate does not solve the calcium problem when dyeing. It’s just as useless for this purpose in a front-loading machine as in a top-loader. Sodium carbonate reacts with the calcium in hard water to form insoluble calcium carbonate, which is deposited not only on the sides of a sink or bathtub, but also on the fabric, interfering with the ability of dye to evenly reach the fiber that you are dyeing. The water in the dyebath is, technically, softened by this reaction, because you end up with less calcium in the water; however, putting insoluble calcium carbonate onto your fabric does you no good at all.

A household water softening device uses a resin to replace the calcium ions with sodium ions, but this is not possible without the water softening equipment. You can’t do this in a washing machine.

Washing soda, including that sold by Arm & Hammer, is nothing more than sodium carbonate with a few extra water molecules complexed to it. It is not better or worse as a water softener than soda ash is; they act exactly the same, which is to say, neither is useful as a water softener for dyeing, and both work very well as a fixative for fiber reactive dyes such as Procion dye. You can always use washing soda (sodium carbonate decahydrate) as a substitute for soda ash (anhydrous sodium carbonate), or vice versa, if you remember that washing soda has more volume and more weight per a given amount of sodium carbonate than soda ash does. You need to use 2.7 times as much washing soda as a substitute for soda ash, if measuring by weight, or 4.6 times as much if measuring by volume, to get the exact same number of sodium carbonate molecules. However, most of our dyeing recipes include a comfortable excess of sodium carbonate, so it’s usually not all that important if you forget to increase the amount you use.

(Please help support this web site. Thank you.)


Does the dye/soda ash/water mixture stay “active” indefinitely, or is there a fixed working time?

Name: Rose
Country or region: New York, USA
Message: Hi, Does the dye/water mixture and does the dye/soda ash/water
mixture stay “active” indefinitely or is there a fixed working time for
both? Thank you.

I’m assuming you are talking about Procion MX type fiber reactive dyes; answers will be completely different for other classes of dyes. There are three different questions here: soda ash, dye dissolved in water, and dye dissolved in water with soda ash added.

1. Soda ash alone, no dye mixed, in plain water, stays good indefinitely. It never spoils. Dry soda ash may absorb a little water from the air so that a given weight or volume actually contains less than you might expect. Not a big deal since we tend to use more soda ash than we really need to anyway. Cover the bucket, when you put it away for the day, to reduce evaporation and prevent rain from falling in. You can use a soda ash solution for weeks, even months, after preparing it.

2. Fiber reactive dye plus water alone (no soda ash) lasts only until the dye reacts with the water it’s dissolved in. This process is called hydrolysis. You can keep your dye stock solutions for a week or possibly more, and they’ll still be good, if not even a single drop of soda ash has gotten into them; if you refrigerate them, they will last three times as long. This is assuming you have average water, or use distilled water; alkaline or acidic water will badly shorten the lifespan of reactivity of the dye. Note that different dye colors have different hydrolysis rates, so a mixture of different dyes will shift in hue, as the fastest-reacting members of the mixture go bad!

3. The dye/soda ash/water mixture maintains its strength for only a brief
period of time; it may go bad an hour after the soda ash is added to the
dye! Be completely ready with everything else before you add soda ash to the dye. In high-water-ratio immersion dyeing, do not add soda ash until after the dye has had time to penetrate the fabric, and, for smoothest results, then add the soda ash in three or more parts, stirring for a few minutes after each addition, rather than adding all the soda ash at once. You cannot reuse a fiber reactive dye dyebath.

(Please help support this web site. Thank you.)


What to do if soda ash makes your skin break out

Name: Bob
Country or region: USA
Message: I have been dyeing for many years. I have had no reaction to soda ash up until about 2 months ago. About that time, I got a huge rash/blisters on my hand that I thought were caused by poison ivy/oak. Now, whenever I touch fabric that has soaked in soda ash, I get pimple-like things on my hands and forearms. I am sure they are caused by overexposure to the soda ash. They are quite irritating.

Do you think my soda ash soak is too “hot”? I have been using 100% sodium carbonate that I buy in ph Up in the pool supply store. Do you think that it would be less irritating if I were to use light soda ash as supplied by ProChem?
I know that you can use soda ash directly in the dyes but it gives you a shorter life for the dyes. I am not sure about that process.

I generally dye about 100 shirts a week, over a 5 day period. I have been dying with procion dyes for 25 years and never encountered this problem before. The weird part is that most of the skin irritation occurs on my left hand while my right hand is relatively free from any irritation.

Thanks for any help you might be able to give me.

Have you been soaking your fabric in soda ash before tying it? If so, the answer is to stop doing that. Moisten your fabric with plain water (a spray bottle is nice for this unless you prefer to soak it) and tie it. Plain water works just as well as water for the tying step, for those who prefer to tie wet fabric, and then, after tying, it can be displaced by the soda ash presoak. After you have tied your fabric, put on heavy duty rubber gloves to place it into your soda ash soak. Use a relatively strong soda ash presoak mixture, one cup per gallon, rather than the nine tablespoons per gallon in the ProChem recipe, to make up for the extra water (though soda ash works well over a surprisingly wide range of concentrations). Get a mop bucket with a wringer to squeeze out the extra soda ash solution after soaking, so you don’t have to handle it so much by squeezing out extra soda ash solution by hand. The spin cycle of some washing machines works well for this step, but other washing machines spray on extra water during spinning, which is no good at all. Wear reliable gloves whenever you’re near soda ash, including your freshly dyed items before rinsing out.

If you are line-drying the soda ash into the fabric before dyeing, after the presoak but before tying, the fabric is probably too irritating for you to handle at all. The dry soda ash tends to get into the air during the tying step.

Adding soda ash directly to the dye works well if you will be using the dye right away, but as you note the dye goes bad only an hour or so after adding the soda ash to it. There’s a good recipe for this technique on my dye thickener page.

To protect your hands while dyeing, try latex-free gloves to see whether a latex allergy might be contributing to your problem; you can choose vinyl or nitrile gloves, instead. There are some nice elbow-length nitrile gloves available for dyeing. Look for the type with a cotton lining, as well as the thinner unlined type for when you need more sensitivity.

Depending on your source of clothing blanks, it’s possible for them to be contaminated with formaldehyde and other chemicals when you receive them. (This is less likely with clothing that is marked “prepared for dyeing”.) Wear gloves to handle them as you place them in the washing machine for pre-scouring.

Light soda ash will not make any difference. It’s the exact same chemical, just a little bit fluffier maybe. It doesn’t matter whether you order soda ash from a dye supplier, or purchase soda ash as a pH increaser for swimming pools; the latter is often more convenient.

There are other chemicals that can be substituted for soda ash, such as trisodium phosphate (TSP), but it seems likely that your problem may be due to irritation from the high pH of the soda ash, rather than due to a specific allergy to soda ash. If this is the cause, then switching chemicals will not help at all, because all of the chemicals that can be substituted for soda ash, for dyeing with fiber reactive dye, produce a similar high pH. It’s the high pH that activates the cellulose molecule so that it can attack the dye molecule. Trisodium phosphate produces a higher pH than soda ash, so it is even more irritating.

All of these high-pH chemicals tend to react with the natural oils in your skin, producing soap. That’s why your skin feels so slippery after you get soda ash on it. What you feel is the newly created soap. It is extremely irritating to the skin to lose the protective oils. In addition to strictly avoiding all exposure of your skin to soda ash, you will need to replenish the oils. Avoid exposure to very hot water. You will probably want to apply lots of moisturizer to your hands frequently throughout the day, especially after every time you have gotten them wet, and before going to bed at night. Be aware of anything that might be causing an allergic reaction; if you are concerned about an ingredient in your skin moisturizer, you can apply plain vegetable shortening, such as Crisco, to your hands. It is distressingly greasy, but very suitable for extremely sensitive skin; some eczema sufferers like to put it on at bedtime and wear thin cotton gloves. If your problem continues after you have stopped exposing your skin to soda ash, you should see a dermatologist.

For more information about soda ash and its role in dyeing, see my FAQ page What is soda ash, and what’s it for in dyeing?

(Please help support this web site. Thank you.)