How to Block Knitted Items. There are many misunderstandings about blocking: that it can change the finished size of a garment, that it's necessary to block all knitted items and that it's a difficult process and something to be dreaded. What is true about blocking is that it opens up stitch patterns, straightens edges and can train fabric into a certain shape, at least for a certain amount of time. Blocking can be done wet or with steam, but either way, it's not the horrible chore many expect it to be; mostly it just takes an undisturbed place to dry after a few minutes of shaping and/or pinning. Here are some tips.
How to Wet Block
Wash the knits according to the method suggested for the fiber it's made of. Press out as much water as possible without wringing or twisting the fibers. Alternately, if a garment is already clean, but still needs blocking, spritzing with lukewarm water until just damp will save you from having to rewash.
Put down a plastic sheet or liner to protect your surface and cover it with a dry towel. You can also set up a mesh drying rack over your bathtub and skip the towels.
Arrange your garment(s) on the towel or mesh rack to dry. Sweaters only need to be laid as flat as possible and allowed to dry over time. Unassembled pieces will benefit from light stretching to set their shape before being seamed.
Pin the corners of lacework or other open-patterned items to your surface and then pin around the rest of the shape every inch or two.
Swap out the towels as they become soaked and flip the knitted items so that the stitches underneath are exposed to the air.
Bolster shaped items that are being blocked to form a curve or that are otherwise not flat with rolled towels inserted in and around the piece. Anything that meets your shape requirements can be used if you wrap the items in plastic to protect them from the moisture (I once used a block of discs wrapped in plastic to block a purse).
How to Steam Block
Lay out towels on a counter, table or bed--any surface large enough to hold the entire article all at once to prevent unintentional stretching from parts hanging over the sides.
Spread out the fabric to be blocked as flat as possible. Have the outside of the fabric face down or inside out. Lacework is an exception, since you need to see the stitch pattern to be opened. Leave it face up and place the pins at an angle to avoid interfering with the steam iron.
Steam each area of your fabric one at a time by skimming the iron just above the surface. Do not press the fabric at all and avoid steaming any of the folds (like those at the shoulders or along the sides).
Arrange the fabric into its ideal shape, stretching gently and adding more steam to open the fibers if necessary.
Let dry completely before turning over or right-side-out, and gently steam out any folds or touch up sections that may need it.
Large items like shawls or table clothes can be blocked on a spare bed or even a floor out of the way of traffic. Stretching knit fabric wide will shorten the length, while stretching it lengthwise will narrow its width. Drying a sweater wider is fine, as gravity will take care of the length once you put it on. Rolled towels or a pressing ham can be used to steam out accidental folds or shape curved seams.
Steam is not appropriate for all fibers. Check your fiber wrappers or test your gauge swatch before steaming your finished pieces.