Mending clothes: patches, hems, zips

Fabric is made of many threads woven or knitted together. If one thread breaks, the neighbouring threads have to take over the load. The forces therefore gather at the edges of a hole – every time you bend down or the trousers stretch, they pull on the edge, and the hole keeps growing.

A patch spreads this load back over a larger area of intact fabric. That is why it must extend a good two centimetres beyond the hole all round, and why it holds best when it is similar to the garment: similar thickness, similar stretch. A thick, stiff patch on thin fabric pulls at its edges and tears the fabric next to it anew.

Hems and zips follow simple rules too. A hem is just folded-over fabric held by small stitches – if the thread breaks, it drops down. A zip works through the slider, which presses the teeth into each other. If it sticks, the cause is often dirty teeth or a slider that has widened through wear.

A simple sewing kit is enough to start: a few sewing needles in different sizes, thread in basic colours (black, white, grey, navy), small scissors, pins or safety pins and a thimble that protects your finger when you push the needle through firm fabric. For jeans and jackets, slightly stronger thread is worth having.

Leftovers from old clothes make good patch fabric – a cut-off trouser leg, for example, provides perfect denim. Cotton goes with cotton, denim with denim. Iron-on patches are quick to apply, but often last longer if you also stitch around the edge.

For zips, small flat pliers help, and for sticking teeth a pencil or a little candle wax. Good light matters more than you think: in poor light, stitches become uneven and you prick yourself more easily.

Three basic stitches cover almost everything. The running stitch is the simplest: needle in, out again a little further on, alternating – quick but not very strong. The backstitch is sturdier: each time you go back a little, so the stitches lie edge to edge like a sewing machine's. The whip stitch takes the thread around an edge and holds hems and patches in place.

Prepare the repair well: wash the garment, trim frayed threads, cut the patch with rounded corners – square corners lift sooner. Pin the patch smoothly and without tension. If the fabric puckers while you sew, it will crease later or tear at the edge.

Zips need a light touch: rub sticking teeth with pencil graphite or wax and move the slider back and forth a few times. If the zip gapes behind the slider, you can squeeze the slider very gently with the pliers – better twice lightly than once too hard, because an over-squeezed slider jams.

Sewing is a calm activity, but needles and scissors are sharp. Keep them in a tin or pincushion, count pins after the work and keep them away from small children. A thimble stops you from driving the needle into your finger when pushing it through.

When ironing on patches, use the right temperature for the fabric – the care label helps. Synthetic fibres can melt or get shiny patches. Never leave the iron switched on unattended and put it down safely after use.

Clothing and equipment whose protective function depends on seams is not repaired by yourself: motorcycle clothing, climbing harnesses, safety harnesses and similar protective gear are replaced after damage or checked by the manufacturer. Waterproof membrane jackets also need special repair material, otherwise they will no longer be waterproof afterwards.

Practise first on a scrap of fabric, not on your best jacket. Sew a few rows of running stitch, backstitch and whip stitch side by side and see how they differ. Make sure the stitches are the same length – that matters more than speed.

After that you can patch an old garment that was going to be thrown out anyway. Learn to tie a knot at the end of the thread and to secure the end of the seam so nothing comes undone. A loose button is also a good first exercise.

In times of scarce supply, mending was a matter of course, and many people could do it as children. Today it is mainly a question of practice and a few tools. Once you can do it, you save money, throw away less and are more independent of new clothes in a crisis. For complex repairs, a tailor remains the better choice.