What Is the Difference Between Fulling and Felting?

Pictured above: a coat of fabric in silk noil and baby alpaca, 

woven in Deflected Double Weave and fulled for warmth and durability

Before I begin, please understand that the coat pictured above is a work in progress: I haven't finished sewing it!

Anyhow, many years ago I was talking with a felter-friend of mine, telling her how I "felted" a hand-knitted hat I had made. She corrected me, telling me that I had really "fulled" the hat -- not felted it -- because felting involves raw fiber while fulling involves fiber that has been knitted or woven.

Here's how the two terms are defined by Britannica.com. (U.S. readers, remember that Brits spell fiber as "fibre.")

Felting, consolidation of certain fibrous materials by the application of heat, moisture, and mechanical action, causing the interlocking, or matting, of fibres possessing felting properties. Such fibres include wool, fur, and certain hair fibres that mat together under appropriate conditions because of their peculiar structure and high degree of crimp (waviness). Wool can produce felting even when mixed with other fibres. 

Fulling, Process that increases the thickness and compactness of woven or knitted wool by subjecting it to moisture, heat, friction, and pressure until shrinkage of 10–25% is achieved. Shrinkage occurs in both the warp and weft see weaving), producing a smooth, tightly finished fabric that is light, warm, and relatively weather proof. A common example is loden cloth, first produced in Austria in the 16th century.

There are a lot of mysteries and opinions (oh my, the opinions!) involving these two processes. Which soap to use? How hot should the water be? Machine wash or hand wash? Do you "shock" the wool by immersing it in cold water after using hot water? Can you heat the fiber in a microwave? And so on. 

I won't be addressing all of these questions; I'm talking about my own hand-woven fabric and how I went about fulling it. Here's the "before fulling" state.

And here's what it looks like after fulling.

And here's another view.

The colors in the photos vary because I used two different painted warps to weave the fabric in Deflected Double Weave. I dyed the silk noil in a range from teal to purple to turquoise and I dyed the baby alpaca warp in a range from lavender to periwinkle to mauve.

You might be thinking: I like the piece before it was fulled. And there's an argument for that, certainly. The main reason I fulled it was for texture: This was to be sewn into a coat and I needed a sturdy, warm fabric for that. I also just love the look of fulled handwoven or hand-knitted fiber: it acquires an organic, more natural look, less angular and tidy -- and to my eye, far more interesting!

Here's a photo of the back of the coat to give you a better idea of what I am going for.

The fulled fabric has a bit more eccentricity and quirkiness, in my view.

I've long pondered the question, "What makes wool felt?" The simple answer lies in the microscopic structure of the fiber. It has tiny scales on it that open with heat and soap and agitation (and pH, when you get really scientific about it) and then lock into each other as the agitation continues.

Here's a photo I found on Pinterest that gives you a microscopic view of a number of fibers. Unfortunately, I can't find where it's from because it's all over Pinterest, with no attribution.

See the scales on the coarse wool and fine wool (first and second fibers on the left)? And see the smaller less defined scales on the alpaca (third from left)? 

Many people will tell you that alpaca can't be felted or fulled -- but that's not really true. It's just that it takes longer to do so.

And I can testify to that. Without going into all the gory details, it took me several days of washing and sloshing my 8 yards of fabric in the bathtub, in the sink, and even in the washing machine. There's even some nudity involved but I won't go into that on a family blog ;o)

I just wasn't getting the results I wanted -- and then I remembered a spinner telling me that she used Murphy's Oil Soap to felt her wool. Murphy's is slightly basic, at a pH of about 11, and that change in pH helps the scales to open which in turn promotes their locking together.

So I tried Murphy's and yes, I did get the results I was after. Not perfect, but close enough. 

And I learned a lot in the process -- which is half the reason we fiber folk enjoy what we do! Thanks for reading.