Fulling and felting

Fulling is the process of fluffing up an already woven or knitted piece of woolen cloth. It's to be distinguished from felting, which takes raw fleece and puts it through the same process without having any initial structure. Felting usually yields a fabric that's a lot stiffer than fulling, since it needs more felting to be able to hang together at all. Fulling can be applied lightly, and simply fluff up a fabric so it ends up softer, fuzzier and thicker (so warmer for the same weight) but still very pliable. A well-known example is loden cloth, developed to deal with Alpine climate, which is knitted before it's fulled. Generally the best candidates for fulling are fairly loosely knitted or woven fabrics, both because that allows more thread movement and makes the process more efficient, and because the resulting fabric is more likely to be satisfactory in weight. There is a fairly new hybrid process called 'nuno felt' coming from Australia via Polly Sterling's work, where a light layer of fleece gets incorporated into a gauzy fabric layer of any fiber, and this gives a very light and airy, sometimes even sheer, fabric.


Felting is one of the earliest forms of textile processing we know. Asian nomadic tribes started spreading all over the continent thousands of years ago. Attila and Genghis Khan are the most well-known of their many rulers, and their names alone still convey the horror felt by the Europeans and Chinese when these much more mobile and flexible people showed up on their doorsteps in later days. Their success was due in part to the domestication of the horse, which allowed them to move great distances quickly. But it was also due to their mastery of felting, which allowed them to withstand some of the most horrible weather conditions on earth in relative comfort, or at least live through them. It's a big improvement on the hides that preceeded it for the same functions, and can be made in a much more portable way than the weaving favored by more settled cultures.

Wool is not just a perfectly-renewable resource, quick-growing and if anything helpful in the harvest to its producer. But it's also one whose source is inherently portable, and in a pinch is a handy alternate supply of food. So it's an ideal material for nomadic survival. Felt gives wool a very windproof quality when it's thick enough, and it gets relatively water-resistant as well. It may be stiff, but it's almost never heavy. Tents made of it are just as liveable as more solid houses, they are light enough to be transported easily, and as a bonus they're fire-resistant and won't kill you in an earthquake. Clothes made of a lighter version act like portable tents, keeping the wearer protected from both extremes of temperatures and from precipitations, while remaining much lighter than the equivalent in other natural materials. Asian nomads also gave the world the pants, which made for much more comfortable horse riding, and which are still the garment of choice for going out and actually doing something.

The process

Felting happens because wool is sheep hair, and like human hair each strand is covered by microscopic scales (you have probably seem vivid pictures in shampoo commercials). The primary mechanism of felting is abrasion, as the individual hairs get rubbed together the scales catch on each other, and the global effect is that the whole thing shrinks in a irreversible way to make a mat that can't be separated. This can be accomplished by stuffing some fleece under your saddle and riding on it all day, which is why the Asian nomads had a natural advantage there ;-). For the rest of us, some elbow grease must be involved, sometimes a great deal of it.

There are ways to make the process easier. Encouraging the little scales to open up vastly speeds up the process and lessens the amount of work necessary. One of the primary ways to do this is by wetting the fibers. Cold water will work, hot water is better. Alternating hot and cold water ('shocking') works best. So fulling is always very wet work, I've done it stomping fleece with my feet like grapes in the bathtub for instance. Soap also helps the process. But we do mean soap, not detergent! We use Dawn dishwashing liquid to wash our sweaters because it's what preserves their condition best, cleaning without stripping, preventing dye bleeds, and not disturbing the scales so there's less chance of fulling. So consequently it's the worst possible thing to use when you mean to full. There is still some liquid soap available on the market, like some varieties of Ivory, or you can use Ivory soap flakes, or even a plain bar of soap. Whatever it is, it must say 'soap' on the package, because if it doesn't it's most likely detergent, even if you don't think of it that way, that's the deal with modern marketing. I believe the slightly basic ph of soap is one of the factors that makes the scales open up further.

There are also moderns ways to cheat mechanically. An old-fashioned washing board is a big help when you're trying to full by hand. It's a good tool, especially for a small project, because you keep an eye on what's happening and you can stop precisely when you reach a satisfactory state, and also because you can full some spots more or less and keep better control on the final shaping. But a top-loading washing machine is also just fine, as you may have discovered when you tried to wash sweaters without your mom the first time. The machine needs to be top-loading, because you must be able to stop it, fish out the items and examine them at short intervals. If you intend to wear something, it's important to keep a tight control on the process so you don't end up with a too thick and stiff or misshapen thing.

One method I like to use is Judith McKenzie's interpretation of an early washing machine. This can be done outdoors, or I prefer a bathtub for easier access to hot water. Also, since I tend to get very wet at this, it allows for the most efficient outfit, none. You need a washbasin of sorts, as filling the whole bathtub isn't practical, and you're likely to slop over so it's much better to do that into the bathtub than onto the floor. And finally, the piece de resistance, you need a toilet plunger. Judith has a lovely one for class use, new, sparkling, bright green with clear handle. Your own slightly used one may seem too gross to consider, but you may also think that after you're done with all that hot water and soap you could probably dish out ice cream with it without any ill effects. In any case, one puts the item(s) in the basin filled with hot water, and agitates the hell out of it it all with the plunger. Water that slops out in the process can be easily replaced with new one, preferably hot enough to fry your neurons on contact. The ergonomics of the plunger allow for much more and longer agitation than anything else would, and you get very good eyeball control of the process. This method is the best for items that are fairly loose and large, so they'd get deformed in a washing machine and are too big for the board, and it's very efficient.

Keep in mind that the process of fulling can pick up again at any time. Just because your wool sweater has looked the same for years doesn't mean it can't be ruined by an unfortunate round of machine washing. And after you get a fulled item to the point where you like it, you must then switch to washing it with regular wooly precautions. If you submit it to more wet abrasion, it'll full right past the desirable point on you.

Reversal - not!

It's worth mentioning also that there is a lot of mythological stories out there, specially on the net, about miraculous recipes for reversing fulling. They mostly involve soaking in various substances, but while I haven't personally tried them all, I'm pretty sure the textile people would have noticed such a staggering technological advance and talked about it at length :-)... None of these methods as far as I can see involve anything terribly modern or sophisticated, they are mostly on the level of soaking/boiling in vinegar/soda/cow urine for a few hours/days, all ingredients and processes that have been available for centuries. As you know modern science is busy giving us more polyester, rather than working on this problem. But if you think about the structure involved you can see for yourself that new chemicals aren't likely to help either.

The most you could accomplish with all this would be to stretch out and essentially block an item that had been only lightly fulled. Which has its good points, at least till you're exposed to humidity (San Francisco fog, anyone?) and the item goes right back to its altered state... If you're enclined to waste your time this way, you can simply go with a vinegar rinse, on the principle that acidic environments will tend to smooth the remaining unoccupied scales, but don't get your hopes too high.

First published: 7/18/02

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