Today I want to talk a little about suitability of fibre to project, but this article is mainly about sampling…boring but essential! I hope you find some (or all) of it useful. Scroll to the bottom of the page for detailed sampling instructions, or take a look at my slideshow. 

We all do it – buy beautiful fleece for a project because of its colour/tactile characteristics/look etc. We might even have a project in mind, and want to get right down to it. We get our fleece home, start spinning or felting it and find that it’s not really what we wanted for that project after all, or that it doesn’t work with the technique we want to use. 

There is only one answer for this – you must match your fibre to its end use before you start your project! If your fibre doesn’t match your end use, you will never be satisfied with the finished work. After sampling, you will, of course, be able to either adjust your project or send the wool to your ‘later’ stash! 

So how do we go about making sure the project matches your original vision? The answer lies in buying the correct fibre for the project, and then sampling to make sure that it will work the way you expect.  

I know a lovely old lady who was repeatedly puzzled about the way her knitting never turned out the way she had intended. Indeed, her garments were always too big, too small or strangely distorted.  

Part of the problem was that she was using yarns that were very different from those recommended in the pattern (she wasn’t a spinner), but I got to the bottom of the problem with one question:

“Do you sample?” 

“Oh, goodness no, I haven’t got time for that nonsense!” 

It’s all quite logical, really. For example, for a really fine knitted or felted scarf you will need a very fine Merino fleece (19 microns or less), whereas for a felt hat you would probably want something a bit ‘meatier’, say a strong Merino, Corriedale,  or even Romney, depending on the look you want.  

If you are felting, sage advice tells us to keep right away from any Down breeds such as Perendale, Suffolk, Southdown. These are wonderful spinning breeds but do not make lasting felt; in fact some of them don’t felt properly at all! Good reason to buy your fleeces for felting from reputable sources. 

No type of wool that has been superwash treated will felt, as it has been altered to prevent felting during washing. And if your generous neighbour has given you a fleece and doesn’t really know what it is, sampling will help you decide whether it’s more useful for making craft items or compost (as is often the case). 

Don’t be tempted to miss out the sampling step – it’s the only way to find out what you need to know about your fibre and technique. Keep a sample book to refer to – it will help you with project ideas and it’s a great resource to share with fellow crafters. I put samples mounted on card into a clear book and keep records of all the details of each sample.
 
Click here to see a slideshow of my sampling process

Sampling for spinning
Make sure you use all the techniques available to you and make several samples. Try to match the twist in your finished yarn to the crimps in the fibre. If you’re spinning sliver, pull several strands and look at them under magnification.

• Count the crimps per inch (CPI) in each fibre and average them. This will give you the number of twists per inch (TPI) that you will need to make your final yarn the perfect match to the fibre. You will have to add more twist than CPI (because plying partly untwists your singles).
  
• Calculate the TPI for the singles, then for plying 
  
• Anne Field’s Spinning Wool: Beyond the Basics (Shoal Bay Press, 1995) is an invaluable resource for spinners. Alongside a wonderful breadth of information about fleece, preparation and matching fleece to project, it gives detailed instructions on how to match spin and ply to twist.Make a few samples using different spinning styles; e.g. short backward draw, long backward draw (my favourite), spinning on a core etc.
  

Wash the samples and then make a square matching the final project. This must be at least 15cm square – skimping here can skew the final result. 

Once you have your finished, washed, pressed square you can check:

• Does the sample look as you expected?
  
• Is your spinning technique up to the project you envisaged?
  
• Is there another technique you should explore before going ahead?
  

Sampling for feltmaking
Pat Old once said to me that ‘feltmaking is a craft with more than the usual amount of disasters’. The only way to minimize the disasters and make the most of your fibre is to sample, sample, sample. 

Every different fleece has its different characteristics; every batch of sliver will reflect the characteristics of the fleeces used to produce it. When the finished size of the piece is critical, it’s essential to thoroughly test for each and every project.

Basic Felting Tests
The rough ‘will it felt?’ test:
Take half a handful of fibre, then compact and form into a small ball by rolling in the palms of your hands.

• Dip the ball into hot water with your soap or detergent of choice (I always use Lux flakes)
  
• Squeeze most of the suds out, leaving enough to nicely lubricate the wool
  
• Begin lightly rolling the wool between your palms. Depending on the fleece, it can be very soft to start with
  
• Continue to roll, increasing the pressure, until you have a nice tight little felt ball. Keep dipping in hot suds to keep it lubricated. If the ball doesn’t tighten up until it’s quite hard, it’s unlikely the wool will felt properly.
  
• Rinse the ball thoroughly in hot and then cold water
  
• Inspect that final product. Is it hairy? Your finished felt will likely be hairy, and may not felt well. Is it smooth, compact and hard? Then your wool will felt well.
  
• Once you are happy that your wool will indeed felt, then move on to making a shrinkage sample
  
• Save up your sample balls to make pins, earrings and necklaces. There are many ways to embellish them and they make terrific gifts! 
  

Sampling for shrinkage (wool felt):
Felt will shrink most along the length of the fibres; if you want to make felt that shrinks equally, you will need to lay even numbers of layers of fibres in opposite directions. If you use odd-numbered layers, make sure you mark your sample in some way so that you know which edge is which. 

• Take a piece of netting, plastic or whatever you usually use to make your felt
  
•  Lay out a sample at least 20cm square in the thickness you want for your final project. Draw around the sample on a plastic square with permanent marker and put to one side. You will use this to check your progress.
  
• Lay a covering over your sample
  
• Felt the sample using your usual technique, using the template you made to check that it is shrinking. Usually the sample will get bigger as it absorbs water and then start to shrink as you work it.
  
• When it’s holding together, start to full the sample using your usual techniques
  
• When completely fulled, rinse out your sample in hot, then cold water; dry and finish in the usual way. Check your sample against the original template.
  
• Measure the difference and convert to a percentage. This is how much shrinkage you can expect overall in your finished felt. You can then calculate the size of your felt pieces accurately. Many finer wools will shrink around 50% when properly fulled! 
  

Note: it is very tempting to stop fulling when the fabric is still loose so that it will be flexible. It’s better to choose a finer wool and full adequately than to do this; inadequately fulled felt will never wear as well or look as good as well-fulled felt.

Sampling for shrinkage (Nuno-felt)
You can combine fabric/fibre compatibility with sampling for shrinkage in nuno-felt. If you have problems with nuno-felt, often it's not the wool's ability to felt that is the problem - it's the combination of wool, a particular fabric and technique. Not all wools are equal - some will require different treatment from others. Technique is very important here – persuading the little fibres to mesh with the fabric can be tricky and some wools will need more help than others.

• Cut at least a 20cm square of your chosen fabric – if you are using heavier fabric, use a larger square, but make it in increments of 10cm – it will make your final calculations easier.
  
• Cover the edges and lay out your sample in the pattern you intend to use for your finished work. This is important if you are using a multi-directional pattern as the fibres will shrink up in different directions, which makes shrinkage unpredictable.
  
• Again, using a square of plastic, make a template drawing around your sample with a permanent marker and put it to one side for reference
  
• Using your usual techniques, wet out your sample and work it to a soft felted stage
  
• Full the sample completely, rinse with hot then very cold water, dry and finish as usual (I steam or damp press at this stage to give a smooth, even finish)
  
• Use your template to determine shrinkage as above for wool felt 

Now excuse me for being a bit of a nerd, but I thought you might like to know how the felting process works. If you already know - well, you can skip this one!

Felting is a innate characteristic of wool fibre. This means that unless the wool is treated in some way (more later), whether they are spun and knitted, crocheted, woven or just felted on their own, wool fibres tend to felt. Our distant ancestors in Europe and Asia knew this through experience, but the clever scientists of the 20th century found out why.

 This is important because once we know how to felt, we can either encourage or avoid this tendency in our woolcraft items.

Soooo...the wool industry has brought out Superwash wool, mostly because the invention of easy-wash fabrics has gutted the wool textile industry over the last fifty years. Let's face it, coming home from work at 6 p.m. and doing the woolies has never been that attractive a prospect! Polar fleece, in particular, was a strong influence on the downturn in the sale of woollen garments, because we could now be kept warm in things that were cheap and could be thrown into the washing machine. Millions of dollars have been spent inventing alternatives to a fibre that was already plentiful and easily washed - as long as you stuck to the rules!

But I digress...Superwash is a process that strips the tiny scales off the wool fibres and applies a chemical coating to the fibre, preventing dirt and liquids from penetrating. This also prevents stains from getting in, of course, and allows the fabric to be machine washed. These are fantastic innovations, but they cut right across the characteristics needed to make felt, which is why you must always ask "Is this fibre Superwash treated?" if you want to make felt from it.

The three things needed to make felt from wool fibre are:

• moisture
• heat
• movement

This explains why jerseys are prone to matt in the armpits, doesn't it?

Wool will felt if these things are combined. The two most powerful factors are moisture and friction; heat just speeds the process. Now why does this happen? the answer lies within the fibre structure. 

Each fibre consists of an outer layer which is made of overlapping scales, and an inner core which consists of two separate compartments, one which accepts and one which repels moisture.

If the wool becomes wet, the moisture-accepting core swells while the other core doesn't, forcing the fibre into a curve. In this state the wool becomes very prone to felting, because as the fibre curves, the scales one one side open up and can easily become enmeshed with other fibres. If any friction is then applied to the wool, the scales become even more enmeshed, and a further property of the wool is activated. 

Each fibre will shrink up to 50% of its length, in one direction only, from root to tip. This is an irreversible process. Heat accelerates the shrinkage of the fibre, and this is why most modern feltmakers prefer to use hot water. the addition of soap or detergent to the water merely make the water penetrate more quickly into the fibre, as well as providing a useful lubricant to allow the scales to slide together more easily.

From what I've just said, it's easy to see why careless handwashing or machine washing can completely ruin wool jerseys. 
A word of warning: felting doesn't stop when you want it to! Any felted item must be treated the same as fine knitwear - that is, it must be gently washed with an appropriate detergent, avoiding sudden temperature changes. It should be dried flat away from harsh light (particularly when dyed - no dye is entirely unaffected by strong UV light), and stored where insects can't attack it.

Felting (or fulling) has been applied to woven fabrics to make them more stable, warm and durable since time immemorial, and the first felt appears to predate the Roman empire. How exciting to be able to take part in a craft that spans a large part of the existence of humanity!