Sometimes, knitted pieces are not just wash-and-wear, or wash-and-use. In order to turn some knitted items into something functional and beautiful, the practice of blocking may need to be employed.
The term "blocking" refers to setting the knitted stitches in place with pins and, most often, water onto to a board to even out or shape an item. Blocking has several uses in knitting: one of the most common uses is to open up the holes in a lace project. Lace usually is knitted on larger needles than the yarn weight requires, so blocking an item can open up the loose stitches and show off their pattern or design more clearly.
Other great uses for blocking is to ensure garment pieces are uniform or compatible in size, to prevent stockinette stitch from rolling (this is a common trait of stockinette stitch), or to just make a knitted item look crisp and "finished." Some items are blocked on a board, while others are blocked in the air using wires or a mesh panel. Not every item needs as much work to block, however; some can be evened out using a steam iron.
Some fibers and yarns are more blocking-friendly than others. For instance, animal and plant fibers such as wool and cotton, respectively, have more of a memory to them when they are blocked. The synthetic fibers, such as nylon and acrylic, do not have the same memory or elasticity so blocking may not help as much to hold its shape. Also, the ligher-weight a yarn is, typically the better it will block. There are exceptions to this rule, but generally since bulkier yarns have more volume and diameter, the blocking process may take longer to get the same result as using thinner yarns.
There are several different blocking methods that can be employed. Wet-blocking involves immersing an item in water with no agitation, absorbing the excess water in a towel, and then pinning the wet item into shape on a board to be allowed to dry. When the instructions for an item call to "block to measurements," or to make the knitted piece a very specific size, this is usually the best blocking method. Steam-blocking involves shaping or pinning the item first, and then holding a steam iron over the item at a distance of one to two inches. Generally, the number of pins needed is dictated by the size and style of the piece; lace items may need a pin every half-inch or so, in order for the design to keep a uniform look in its design.
Three cautions when blocking items: cables, ruching, and ribbing are not necessarily blocking-friendly. All three of these stitch techniques rely upon the elasticity of the yarn to do a lot of the shaping for the knitted piece, so wet-blocking a cable or ribbing pattern may cause it to lose its shape, depth, or elasticity. Blocking ruching, or intentional gathering of stitches, can actually cause the piece to flatten.
If you are new to blocking, the best practice is by knitting a gauge swatch and then laundering it as you would the full garment or item before blocking it. You can determine how much blocking an item will need to fit particular measurements, for instance, and see how colorfast your yarn is, by using this practice.
Blocking may feel like a waste of time when doing it. After all of the time invested in knitting, having to block an item may invoke resentment or impatience. Blocking, however, is one of the best insurance policies for making sure your garment will look beautiful, professional, and sometimes, perfect.
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