Monday, March 21, 2016

The science-y stuff

Okay, I will be honest....when it comes to the science, I tend to be more of a Penny and less of a Sheldon (mostly because I get distracted by shoes easily)... but there are some things you need to know if you are going to use food safe dyes to dye your yarn. 

Disclaimer - I am by no means any kind of an expert! Any information I give you in this post is based on research I have done, and mistakes I have made (also known as "trial and error").  I will give you as much of "how" as I can, but there may not be as much of the "why".  Use this information at your own risk :)

#1 most important science-y fact - this method of dyeing only works on animal fibres. This will not work on acrylic, and will not work on plant based fibres, like cotton. For the plant based fibres, you may be a sort of stain, but that will eventually wash out.   

This method is meant for wool, cashmere, llama, yak, silk, nylon, etc.. And you can dye your fibre at any stage. I have yet to get into spinning, so at the moment, I dye the yarn itself, but you can also dye roving, before you spin it into yarn.  And, if you want to be super adventurous, you can knit your item first and then dye it afterwards.

For the sake of these posts,  I will just say yarn, but know that it can mean whatever incarnation of the fibre you want it to be.

So what is required to make dyeing with food colouring work?
  1. Yarn 
  2. Colour - food colour, unsweetened Kool Aid from the envelopes, Easter Egg Dye tablets
  3. Acid - Already in the Kool Aid envelopes, but you may need more for soaking
  4. Heat
That is it. I was tempted to put "patience" as number 5, but we all know by now that I am lacking in that respect, so why post it? These really are the main 4 things you will need to make this work. 

The acid and the heat are the two more important parts to making your colour permanent. You can soak your yarn in water and food colouring, and the yarn will change colour, but it is not permanent, and will wash out/fade.  If you want the colour to be permanent, that is where the acid and the heat come in. 

Kool Aid already contains citric acid, so if you are using the envelopes of Kool Aid, you already have this part covered. There is usually enough citric acid in the Kool Aid envelopes that you can even add some additional food colouring and still have the colour bond to the yarn.  

If you are not using Kool Aid, then you will need to add acid to your process. I like to use citric acid, which I buy in bulk at the wine making store, but you can also use vinegar. 

When to add the acid can depend on a few factors, and I will most likely go through these in more detail as I get into the specific techniques of dyeing, but it is worth mentioning here.  

When I do my hand painted or speckled yarns, I soak my yarn in a combination of citric acid and water. I typically add one tablespoon of citric acid powder to the large Tupperware container, then add warm water and put my yarn in it. I gently push the yarn down into the water until it is submerged and most of the air bubbles are out, then let sit for at least half an hour.   By doing this, the yarn is ready to bond to the colour as soon as it is applied. I do not need to add any acid to the dye stock itself. These methods are heat set in the microwave, so there is not other change to add the acid. (more on that in the Heat section below)

When I am doing an immersion dye (where the yarn is actually immersed in the dye stock), the citric acid gets added to the dye stock itself. But when it is added here can have an impact on the results you get.   If I am going to soak my yarn first, to ensure a more even colour distribution, I do not add acid to that soaking water 
  • For most colours, I will add the citric acid when I add the dye to the water. I like to mix my citric acid powder in a ratio of 1 tablespoon of citric acid to one cup of water, and I usually add 1-2 tablespoons of that mix to the dye stock. There are some exceptions to this rule, though
    • If I am using a dyestock that has Red #3 in it, or if I am using certain blues, I do not add the citric acid until after the yarn had has a chance to absorb a lot of the colour, and the water has been brought up to temperature  
      • Red #3 can do something called crocking, which causes the colour to rub off on your hands when the yarn is dry. This happens because the colour has not properly bonded. This is often caused by too much acid in the dye bath, or the acid being added at the wrong time. 
      • Some blues and purples seem to lose some of their red pigment if the acid is added right away, or if there is too much acid. 
This is another crucial step to getting the dye to bond to the yarn.  You need to bond the dye to the yarn to stop it from washing out.  From everything I have read and been told, the magic temperature for heat setting is 180 degrees F (82 C).  You should also keep the yarn at this temperature for 20 minutes.  The 20 minutes seems to be a widely debated topic, but I will tell you that for immersion dyeing, I have had bad experiences if I don't use that 20 minute rule, so I tend to stick with it.  

There are various methods of heat setting, but in this post, I am only going to cover the ones I use, since I really don't have a lot of information on the other methods. I may add more details later on, but for now, I will stick with what I know. .

This was my preferred method of heat setting for about a year and a half, and is the method I still use for any of my hand painted or speckled yarn.  I dye my yarn, wrap it in plastic wrap, put it on a very large plate, and pop it in the microwave. It is very important that all of your yarn is damp, and that all of it is covered in plastic wrap. Even if you are leaving a section blank, make sure it is damp and wrapped. 

My typical routine is to microwave it in 2 minute intervals on high, and I do this 5 times,  for a total of 10 minutes. I don't like to put it in for the full 10 minutes all at once, because I want to be able to check it in between to ensure the yarn is still safe inside the plastic wrap. If the wrap comes off the yarn (which may happen since the yarn expands with the steam from the yarn), the yarn may scorch.  So checking after each 2 minute interval is a good way to make sure this does not happen. 

This will definitely bring the internal temperature up to the 180 F range, if not higher. And it usually takes at least 10 minutes before it is cool enough for me to remove the plastic wrap, so the yarn gets the time it needs at the temperature it needs.  

I have only used this method on superwash wool, but I know others have used it on regular wool. I do not know if you need to adjust the power level or length of time if using a non-superwash wool, so if that is what you are using, you may want to do a bit of research first. I will try to ask around before I get to my hand painting post, so I can add that information. 

I use this method with all of my immersion dyeing. This method involves using the stove to bring the dyestock up to the correct temperature and hold it there for the correct amount of time.  Depending on the result I want, I will add the acid at different times, and I may add the wet or dry yarn at different times as well. I will get into that more as I do the posts on the specific methods. 

I will typically bring my dyestock up to 180 degrees F and keep it at that temperature for at least 20 minutes, sometimes longer as I am waiting for the dyestock to exhaust. It is sometimes necessary to add more acid to the dye bath to help with the absorption of colour. And in some colours (blues especially), it is quite helpful to turn off the heat and just walk away, sometimes as long as overnight, while the colour sets. 

You need to be really careful when using the stovetop method, especially if the yarn you are using is not superwash. If the water gets too hot and starts to boil, you may felt your yarn. 

This was not on the list above, but is something I have recently been looking into, and has a scientific application (that I am still looking into) so I wanted to add a little bit about it.  I have read that adding salt to the dyestock can help slow the absorption of the colour, which should help you end up with a more even colour through your yarn.  This is still very new to me, and on the occasions that I have tried it, I have used 1/4 tsp of non-iodized salt per 100g of yarn.  I will most likely add a separate post about salt, once I have done more research.  Gynx (Laura) from The Dyers Notebook, was kind enough to answer my question about salt in episode 152 of her podcast, and she even gave me some links to check out.  So if you want more information before I am able to get around to writing that post, you may want to check out that episode. 

Coming up on The Impatient Dyer....
I am hoping that my next post will be me actually documenting and explaining one of my methods. I am going to start with hand painting, since that is where I started. I will give you all the step by step instructions for how I get the skein that I will show in that post.  This one may take me a couple of days, due to some time constraints, so please be patient. 

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