I sewed up the back and worked in the loose ends last night. I went with a fairly tight gauge--about 5 stitches per inch--so it would be extra-thick and warm.
I'm glad you asked! The gauge of any knit or crocheted item can be measured by counted the number of stitches in one inch across. Seriously, you can calculate the gauge on that sweater you bought at the Gap. You probably have no need to, unless you want to make one just like it, but you could.
The type of gauge needed for a project depends on two things: thickness of the yarn and how loose or tight you want the finished item to be. This hat is made from worsted-weight yarn, which is the most versatile yarn weight. You can really use almost any needle size, depending on the look and feel you want for your project. For something you want to be very tight, like mittens, the needles will be very thin (size 2 or 3) and the resulting mitten will be sturdy enough to keep your hands warm in the coldest weather. Hats and sweaters are worked on medium-sized needles (size 6-8) for an item that is sturdy but still has enough stretch to fit over your head. Items like afghans can be worked on needles that are even larger (size 10-11), although those patterns will probably incorporate something like slipped stitches to keep the gauge from getting too loose.
For this hat, I used size 6 needles. This meant that I needed more stitches in each row, so the hat took a little longer to make. It also means that the logo in the middle is smaller than it would have been with a looser gauge. Incidentally, if you want to figure out how big a design will be, it is a simple matter of dividing the number of stitches in your design by the number of stitches per inch.
For example, my Mario design is 14 stitches across at the widest point. 14/5=almost 3 inches. Most hats are worked on slightly larger needles for the yarn I used (size 7 or 8) for a gauge of about 4 stitches per inch. 14/4=3.5 inches.
As your reward for slogging through all the knitter's lingo and math talk, here is a Styrofoam head wearing the Mario hat!
Yes, I just happened to have a Styrofoam head in my apartment. It belongs to my hubby, who got it with his Emperor Palpatine mask. Incidentally, those white streaks you see on the hat came from the baby powder that he puts on the mask to keep it from cracking. Whoops. Good thing my hat is washable.