Felting Sweaters: How to Felt a Wool Sweater, and What to Make From It

Felting a sweater on purpose is the laundry accident everyone has had, pushed further and done deliberately. The result is no longer knitwear. It is a dense, windproof wool cloth that you can cut with scissors and leave unhemmed, and it comes in whatever colour the thrift store had that week.

Whether it works depends mostly on the sweater you start with, so that comes first. After that the process is simple, and most of the craft is in using the fabric well.

Will this sweater felt? Read the label first

Label says	Will it felt?	Why
100% wool, lambswool, Shetland	Yes, well	Untreated scales lock together readily
Merino	Yes, soft and fine	Fine fibres felt fast into a thinner cloth
Cashmere, alpaca, mohair, angora	Yes, fast	Watch it closely; these overshoot
80% wool with nylon or acrylic	Usually	Slower, and a little looser
Under about 70% animal fibre	Poorly	The synthetic content holds the knit open
Superwash, machine washable, "shrink resistant"	No	The scales have been removed or coated
Cotton, acrylic, any plant fibre	No	No scales at all

If there is no label, snip off a bit of the hem and shake it in a jar of very hot soapy water for five minutes. If it thickens and the stitches blur, the sweater will felt. If it looks exactly the same, it will not, and why won't my wool felt explains the rest of the ways it can fail.

Two things that do not matter: size and style. You are buying fabric. A huge men's sweater with a moth hole in the front is worth more to you than a pristine small one.

How to felt a sweater in the washing machine

1. Bag it. A zipped pillowcase or a laundry bag. Felting sheds a surprising amount of fluff, and it belongs in the bag rather than the pump filter.
2. Add something rough. An old pair of jeans, two or three tennis balls, or wool dryer balls. Friction does as much of the work as heat.
3. Use a teaspoon of detergent. It helps the fibres open. More than that only makes rinsing harder.
4. Choose the hottest wash, the longest cycle and a cold rinse. The jump from hot to cold helps.
5. Check after one cycle. Felting cannot be undone, so it is always better to run it again than to wish you had stopped.
6. Dry it. A hot tumble dry tightens it a little more; drying flat keeps it where it is.

Top loader or front loader

	Top loader with agitator	Front loader
How well it felts	Fast, often done in one cycle	Slow, usually two to four cycles
Best setting	Hot, heavy duty, long agitation	Hottest cotton or sanitise cycle; never "wool"
Friction to add	One pair of jeans	Jeans, a towel and several tennis balls
Checking part way	Easy: lift the lid	Often locked; plan on full cycles

High-efficiency top loaders without a central agitator behave more like front loaders. The "wool" and "hand wash" settings on any machine are designed to prevent exactly what you are trying to do.

How to felt a sweater by hand

This takes 20 to 40 minutes of hot, wet work, but it gives you the most control. It is the better choice for a single cashmere sweater or for felting only the sleeves.

1. Fill one bowl with water as hot as rubber gloves allow and a squirt of dish soap. Fill a second with cold water.
2. Squeeze, knead and rub the sweater against itself in the hot water for two or three minutes.
3. Move it to the cold water and keep working it.
4. Go back and forth, checking every few rounds.
5. Stop when you cannot pick out individual stitches. Rinse, roll it in a towel and dry it flat.

A washboard or a ridged bamboo mat speeds it up considerably. The soap you use makes less difference than people think; best soap for felting covers the details.

How much it shrinks, and when to stop

Expect 20 to 40% off the length and 10 to 30% off the width. Sleeves shrink more than the body, ribbing shrinks most of all, and synthetic sewing thread in the seams does not shrink at all, which is why seams pucker. The numbers by fibre are in how much wool shrinks when felted.

It is done when a snipped edge stays put. Cut a small notch in the hem: if the stitches hold, stop; if they start to run, give it another cycle. Going too far is possible too. An over-felted sweater turns stiff and cardboard-like, hard to sew and hard to shape, so for most projects aim for dense but still bendable.

When it goes wrong

What you see	Cause	Fix
No change after two hot cycles	Superwash or synthetic blend	None; use it as a sweater, or unravel it for yarn
Felted in patches	Uneven agitation or a crowded drum	Felt it alone, with more friction, one more cycle
Stripes felted at different rates	Different yarns in each colour	Normal; cut the pieces from one colour area
Puckered seams	Synthetic thread does not shrink	Cut the seams out before using the panels
Stiff and board-like	Over-felted	Use it for bags, coasters, trivets and bowls
Fuzzy, pilled surface	Long, loose fibres rose in the tumble	Shave it with a fabric shaver or shear it close

Cutting a felted sweater for the most fabric

Decide what you are making before the first cut, because placement decides how much you get.

1. Cut off the sleeves just inside the shoulder seam.
2. Cut up both side seams and across the shoulders to get two flat body panels.
3. Open each sleeve along its underarm seam.
4. Leave the cuffs and hem attached where a project can use them. They are finished edges you cannot make as neatly yourself.
5. Keep the neckband. It becomes a mitten cuff, a bag handle or a headband.

An adult sweater gives two body panels of roughly 45 × 50 cm and two sleeve pieces: about half a square metre of fabric. Press any wavy panels flat with steam through a cloth before you mark them out.

What to make from felted sweaters

Project	Fabric it takes	Worth knowing
Mittens	Both sleeves, or one panel	Two or three pairs per sweater; the cuffs become the wrists
Fingerless gloves	One sleeve	Cut to length, snip a thumb hole, done
Coasters and trivets	Offcuts	Use the stiffest, most over-felted pieces
Christmas ornaments	Offcuts	Patterned knits make instant "ugly sweater" ornaments
Hot water bottle cover	One sleeve or one panel	An adult sleeve is often exactly the right width
Cushion cover	Both body panels	Envelope back; reuse the sweater's own buttons
Tote bag	Both body panels plus a sleeve	The sleeve or neckband makes the strap
Slippers	One or two panels	Layer two thicknesses for the sole, or add a proper slipper sole
Patchwork blanket	Six to eight sweaters	Butt the squares edge to edge; there is no seam allowance to lose
Rug	Several sweaters	Strips stitched onto a heavy backing

Scraps are still useful. Chopped small, they make good stuffing for cushions and toys. A flat piece is an ideal base for needle felting on fabric or a wool painting. Pulled apart, felted sweater turns into short, matted fibre that works fine as core wool inside a needle felted sculpture, where no one will see it.

Sewing felted wool

• Long cuts with sharp scissors. Short snips leave a chewed edge on thick felt. Pinking shears give a decorative edge if you want one.
• Zigzag or stretch stitch. Felted knit keeps a little stretch, and a straight stitch can snap under strain.
• A 90/14 or denim needle for two layers; a walking foot stops thick layers creeping.
• By hand, blanket stitch in wool or embroidery floss is both the seam and the decoration.
• Butt joins for patchwork. Lay the edges side by side and zigzag across them, so the seam stays flat.

Before the sweaters join your stash

Wash and freeze anything second-hand first. Thrift-store wool is the easiest way to bring clothes moths home, and a felted stash is exactly what they like: see protecting wool from moths. Store the panels flat and clean.

If you would rather felt something you knitted yourself, sized so it shrinks to fit, that is felting in knitting. If the sweater did not felt and you want a new colour for it instead, see dyeing a wool sweater.