Sewing with fleece: warm layers without a serger

Fleece is a napped polyester knit that does not fray, hardly shrinks and forgives most mistakes, which makes it one of the easiest fabrics to sew without a serger. Use an 80/12 to 90/14 universal or stretch needle, polyester thread, a straight stitch at 3–3.5 mm or a narrow zigzag, trim the seam allowances to 6 mm (1/4 in) and leave them unfinished, and keep the iron off the fabric. The one thing it demands is patience with lint.

Quick reference: how to sew fleece

What is fleece and which kind should you buy?

Polar fleece is a polyester knit that is brushed on one or both sides and then sheared to an even pile. It traps air, so it is warm for its weight, dries fast and does not absorb much water, but it is not windproof. It is sold by weight: labels such as 100, 200 and 300 roughly track the grams per square meter, so 100 is a thin microfleece for linings and light tops, 200 the standard mid-weight for jackets and joggers, and 300 a thick outer layer. Anti-pill fleece has a treated face that stays smooth after washing and is worth the small premium for anything you will wear often.

Related fabrics behave differently. Minky and plush have a long, silky pile and much more stretch, which makes them slippery to sew. Sherpa has a curly face and a flat knit back. Cotton sweatshirt fleece is a brushed French terry, a different fabric with its own rules. Polar fleece stretches 20–40 % across the grain and little along it, and its recovery is moderate, so elbows and knees can bag in a thin fleece.

Which side of fleece is the right side?

Often the two faces look identical. Three tests settle it. Stretch a cut edge across the grain: fleece usually curls toward the wrong side. On a print, the color is sharper on the right side. On anti-pill fleece, the treated face is the smoother one and is the right side. Decide once, mark the wrong side of every piece with a chalk cross or a bit of tape, and stay consistent; the two faces wear differently even when they look the same on the table.

Do you need to pre-wash fleece?

Polyester does not shrink, so pre-washing is optional. A cool wash with no softener and a low tumble or air dry gets rid of loose lint and the finishing from the mill, and it tells you how much the fabric sheds. Never dry fleece hot: the pile flattens and can melt.

How do you cut fleece?

• Fleece has a nap: brush the face with your hand and it is smoother one way. Lay every piece with the top pointing the same way, or the panels will shade differently in the light. A with-nap layout takes 10–20 % more fabric than the quantity on the pattern envelope.
• Cut thick fleece in a single layer. A sharp rotary cutter or long shears both work; the fabric is dense and dulls blades, so expect to change the blade.
• Pattern weights and clips hold better than pins, which sink into the pile and get lost.
• Mark with chalk, a sliver of soap or a washable marker on the wrong side. Cut notches as 3 mm (1/8 in) snips.
• The greatest stretch runs around the body.
• Vacuum the table and the floor before you go to the machine.

Which needle, thread and stitch work on fleece?

A universal 80/12 or 90/14 sews most fleece without trouble; if stitches skip, switch to a stretch or ballpoint needle in the same size. Polyester thread matches the fiber and has enough give. A straight stitch at 3–3.5 mm suits the seams of a jacket or trousers, which stretch little in wear; a narrow zigzag of 1.5 mm × 3 mm is for hems, neckbands and anything that must stretch. Use a 1 cm (3/8 in) seam allowance and trim it to 6 mm after sewing, especially where seams cross.

Two layers of fleece are thick and spongy, and the top one creeps under a standard foot. A walking foot feeds both layers together; failing that, lower the presser-foot pressure and sew slowly. Where a seam crosses another, put a folded scrap of fleece behind the foot so it stays level and does not stall. Clean the bobbin case and the feed dogs after every fleece project: the lint builds up fast and causes thread jams. Sewing knit fabrics on a regular machine covers the stitch settings in more depth.

How do you finish fleece seams without a serger?

Fleece does not fray, so the raw edge is a finish. The question is only how to keep the seam flat.

• Raw and topstitched. Finger press both allowances to one side and topstitch 6 mm (1/4 in) from the seam with a 4 mm stitch. This is the standard jacket seam: flat, strong and tidy on both sides.
• Zigzagged together. A 3 mm × 3 mm zigzag over both allowances keeps them paired and lying in one direction. It is not needed against fraying, only against flopping.
• Lapped. Overlap the two cut edges by 1 cm (3/8 in) and sew through both with a straight or zigzag stitch. This gives the thinnest seam of all, useful in a 300-weight fleece at the shoulders.

Finishing seams without a serger shows these and the other options for fabrics that do fray.

Can you iron fleece?

No, or almost never. Polyester melts at iron temperatures, and the pile flattens and glazes long before that. Finger press seams open or to one side, then hold them with topstitching, which is what pressing would normally do. If a seam truly needs heat, use the lowest synthetic setting, a press cloth, work from the wrong side, and hover the iron rather than resting it. Test on a scrap first.

How do you hem fleece?

• No hem. A straight rotary cut is a perfectly good edge on a blanket, a scarf, a cape or the bottom of a casual jacket. A hand or machine blanket stitch along it adds a finish.
• Single fold. Turn up 2.5 cm (1 in) once and sew with a zigzag or a twin needle; a double fold is too bulky.
• Bands. Rib knit or self-fabric bands at the hem and cuffs are the sweatshirt finish. Cut a band at 80–85 % of the opening, seam it into a loop, fold it, and stretch it to fit as you sew, the same way as a T-shirt neckband.

Common mistakes with fleece

• Ironing it. Melted or shiny patches do not recover.
• Mixed nap directions. Panels shade light and dark.
• Double-fold hems and self-fabric facings. Bulky and stiff; use single folds and bands.
• Skipping the machine clean-up. Lint in the bobbin area causes jams and a loud machine on the next project.
• Pulling the fabric through. Stretched seams ripple; let the feed dogs or the walking foot do the moving.

What to sew with fleece

• A sweatshirt or hoodie in 200-weight fleece, with rib-knit or self-fabric bands at the hem and cuffs. Sewly drafts it with 1 cm (3/8 in) seam allowances on knits and lists the band lengths with the pieces.
• Pull-on trousers in a jogger cut, with an elastic waist and fleece or rib cuffs, for lounging and cold mornings.
• A bucket hat in fleece needs no interfacing and no lining: the fabric gives the body on its own.