The Importance of Blocking: A How Tocomments (7) June 12th, 2008
Blocking isn't especially important on some projects (such as hats, for instance), but it can really whip your more intricate pieces into shape. If your project is small, you can block it on an ironing board or any padded surface—no special tools required. I even had a roommate who used to block on the carpet (if you do this, just remember to collect all of the pins when you've finished).
To demonstrate the difference blocking makes, let's start with two unblocked grannies. To block them, you'll need: a blocking board (or padded surface), T-pins (rustproof pins that hold your work in place; to save money, pick them up in bulk at an office-supply store), and an iron with a steam setting. Set your iron to the appropriate heat setting based on the fiber you're blocking, and only use it for natural fibers. (Note: Acrylic fibers should not be blocked with steam heat, as the heat may cause some of them to melt. Instead, pin them into shape, and spray them with water. Let the pieces dry, and remove the pins.)
First, stretch your squares into shape by pinning the corners. Don't go too crazy with the stretching, just gently tug the motif into the desired shape and size. You can place more pins all around the square, depending on your desired level of perfection. If you're blocking multiple squares or a project with size specifications, measure your work to ensure that it is the right size or to make sure the squares are all the same size. Commercial blocking boards are gridded, which will make this an easier task, but a ruler works just as well.
Next, hold your iron about 1inch above the piece. This is very important: do not press the piece, or let the iron touch the fibers, as it will flatten them. Hold the steaming iron over the work in sections, and give each section about 10 seconds of steam before moving to the next section. Allow the work to dry before you remove the pins.
Here's the difference between the unblocked (left) and blocked (right) square (I forgot to take out the pins, but the square does hold the shape once pins are removed). It's definitely worth taking the time to perform this finishing technique; after a few simple projects, you'll really see the difference.