When I buy a new cotton vest or T-shirt, the side seams are always straight and parallel. After a few washes, one piece of material seems to move relative to the other, and the seams are never again parallel. Why is this?
• If you look closely at the fabric of a T-shirt, you will see that it is made up of thin, vertical rows of ribbing. For the front and back to be aligned, these rows must be parallel. This is difficult to achieve. In a factory, multiple layers of fabric will be laid on top of each other before cutting out the T-shirt pattern, so there is a high possibility that the cuts will not fall exactly along vertical rows.
As a home sewer, I often choose T-shirt fabric for its softness and ease of wear, but it does require more care at the cutting-out stage.
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Claire Gregson, Portadown, Co. Armagh, UK
• T-shirt fabric is often manufactured as a tube in which bands of interlooped yarn run through the fabric in spiral rows of stitches. When the tube is slit open to make a flat piece of material, the rows of stitches may lie at a slight diagonal across the fabric. When this fabric is cut and sewn into a T-shirt, then washed, the stitch rows tend to straighten, resulting in the seam twist.
“We’re all familiar with the almost-horizontal position ski jumpers assume – this helps keep them in the air”
Martin Bide, Department of textiles, fashion merchandising and design, University of Rhode Island, US
• T-shirt material is knitted from a continuous thread, forming loops that interlink with rows above and below. The loops allow it to widen in any direction, while narrowing in the direction at right angles, giving you a nice, stretchy T-shirt with a stable shape.
It will stay like that until you wet the material and the threads relax. It is the drying that is crucial to maintaining shape. If you lay out your T-shirt flat and pat and pull it into the right shape before leaving it to dry, it will be fine. If you just chuck it over a line and hope for the best, it will probably end up a different shape. It can still be rescued by reshaping while gently steaming with an iron.
Adrian Foulds, Glasgow, UK
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