So what is felt and why can’t I spin it?

The merino top that went into the dye pot came out and looked like one really long dreadlock! What happened? Can I still spin it? If you desperately want the answer to be yes, I recommend covering your eyes and skipping ahead because you probably won’t like the answer. While the history and how-to of felt has had numerous books devoted solely to the topic, let’s examine felt primarily from the spinner’s perspective, where felt is not usually a desirable quality.

Most fabrics that fiber artists encounter are woven, knit, or crocheted. Yarn or thread used with a method of interlocking stitches creates a flat piece of fabric. On the other hand, felt is a textile created by matting and compacting fibers. Wool has microscopic scales which are barbed. Science hasn’t fully explained how these fibers relate to felting, but they are involved in some way. Once fiber is felted, it is nearly impossible to separate the fibers without damaging them.

The Science!

Repeat after me…


This is the magic formula. This is what makes felt. We can all go home now! What do you mean you want to know more?

Heat encourages the scales of the wool to open, increasing surface area. Moisture acts as a lubricant. Agitation encourages the fibers to slide against one another.  And then the magic of DFE happens.

Directional Field Effect (DFE) is an important term to remember.  It is the closest answer we have at the time of writing this article to why felting occurs.  DFE describes the frictional force or resistance being greater when it is pulled against the scales than when it is pulled with them.  When fibers are tangled together enough, DFE becomes strong enough to hold them together permanently… again, this isn’t a complete answer, but it is what we know at this time.

Not all compacted fibers are felted

Sometimes felt isn’t felt. Are you thoroughly confused yet? A fiber supply can be compacted, but not felted. When a fiber supply is dyed, scoured, or tightly packed and stored, the pressure of the water or storage container removes the air from the spaces between the fibers. In this state, the fibers are difficult to process or draft.  The good news is compacted fibers can be fluffed open and spun. However, if the fibers break, snap, or sound like Velcro being pulled apart, this is a sign that your fiber supply has felted. And if you try to spin felted fiber, you’re going to have a bad time.

Not all wool felts. So, what’s with down breeds?

Out of the hundreds of recognized breeds of sheep, a majority of wools will felt to varying degrees when exposed to the magic formula of wool + moisture + heat + agitation = felt. Our exception to this rule is down breeds of sheep. Down breeds are named for the southern regions in England where the breeds originated, and while their name has nothing to do with their fiber, they all share certain characteristics. The truest of the true down breeds include Dorset Down, Hampshire, Oxford, Shropshire, Southdown, and Suffolk.

True Down Breeds

Dorset Down Shropshire
Hampshire Southdown
Oxford Suffolk

Science hasn’t conclusively agreed on why these breeds don’t felt when compared to other wools. A fiber that resists felting has potential uses in projects like socks, which tend to take considerable abuse. There are also breeds not from the down areas which are referred to as down-like breeds, because they share some of the characteristics of down wools.


1 comment on “So what is felt and why can’t I spin it?”

  1. Pingback: Troubleshooting Scouring – Luthvarian Fiber Arts

Leave A Reply

Your email address will not be published. Required fields are marked *