Hi,

I am getting ready to dye a large batch of shirts for a not-for-profit group and I use Procion MX dyes.

My question is, when I rinse the shirts, I do it in my kitchen sink and hand rinse to remove most of the excess dye, and then wash a few together in the washing machine.

Is there a way to make it less labor-intensive? I let the shirts cure for about 7 days before rinsing. 

Thank you, Todd

Yes, there is an easier way!

Since you are letting the dyes react with your shirts so long (I hope that they are at or above 70°F for at least one day of that time), and since you are using Procion MX dye, all you have to do is dump all of the shirts into the washing machine together. Fill the machine at least partway with cold water first. Wash once in cold water, either with Synthrapol or with no detergent at all, to remove the soda ash and any salt or other chemicals; then repeat two or three times with a little Synthrapol or any other detergent in very hot water, preferably at least 140°F. Hotter water is much more efficient than cooler water at removing the excess unattached dye that can muddy your colors or cause temporary staining, but the initial cool water rinse can be important.

If you wash out your dye before every bit of the dye reaction is complete, you can't use this method. If you wait only four or six hours after applying the dye, some dye molecules will remain that are capable of reacting with the fiber and making permanent stains, in places where you don't want it to. (In that case, you must rinse each individual piece thoroughly, to prevent darker sections of dye from staining lighter sections.) If, however, you leave the dyes to react with the fiber for overnight or longer, at 70°F or warmer, then all of the dye molecules will have reacted. Some of the dye molecules will react with the fiber, while some of the dye molecules will react with water. Once all of the unattached loose dye molecules have reacted with water, they can no longer form a permanent bond to the fiber. These fully reacted, hydrolyzed dye molecules can temporarily stain the fiber, but washing in sufficiently hot water will remove these stains. You can wash out up to about five pounds of clothing (dry weight before dyeing), or about ten adult size XL t-shirts, at a time, in a regular top-loading washing machine.

What I do, after leaving the dyes to react overnight in a warm place, is carry the dyed items into the laundry room on a tray, to prevent dripping. I wear thin disposable waterproof gloves. I keep a pair of child's blunt-tipped scissors near the washer, to use to (carefully!) cut the ties just as I am dropping the things into the washing machine, which is already mostly full of water. I run the machine through one cycle in this cool water, usually adding Synthrapol (but never any other detergent) for this initial rinse. After that cycle completes, I wash in very hot water, with Synthrapol or another detergent. Since I have a "water saver" model of top-loading washing machine, it automatically adds cold water whenever I do a hot water wash, so that the water temperature is never hot enough to remove all of the excess dye, so I prevent the addition of cold water by turning off the cold water faucet to my washing machine as the hot water fills the machine, then turn it on again after the washing machine is full.

It is also a good idea to use softened water for your dyeing, if you have hard water. This can help your washing-out to be more efficient. If you don't have a whole-house water softener for the water supply you're using for your dyes (most water softeners are installed for the hot water tap only), then you will want to buy the dyer's water softener, sodium hexametaphosphate, and add a small amount of it to your dye mixtures and to your rinsing water. Working in several different ways, this helps to brighten your final dye colors, prevents the formation of white insoluble flecks when you add soda ash (sodium carbonate) to water, prevents gelling of the popular dye thickener sodium alginate, and prevents the formation of dye-dye complexes that are difficult to wash out of your fabric after dyeing. It's less expensive than using distilled water, and can be added to your washing machine during washout. Sodium hexametaphosphate, a white powder, is sold by Dharma Trading Company as "Water Softener", by PRO Chemical & Dye as "Metaphos", and by Jacquard Products as "Calgon". Don't confuse this with the "Calgon" liquid sold in grocery stores; liquid Calgon is an entirely different chemical, polycarboxylate, which is not suitable for use in dyeing. Check the fine print and make sure that you're getting sodium hexametaphosphate. See my page "Dyeing with hard water: water softeners, distilled water, and spring water".

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