This isn't one of those t-shirt resize methods where you stitch a seam here and a dart there, and have something at the end that sort of resembles a t-shirt. I totally remake mine, almost from scratch, using a pattern and materials from the original garment. I like a t-shirt to look like a t-shirt, not a botched up mess. It may sound time consuming, but trust me, it's not. And its easy. You should know by now that I don't do hard!
I have a favourite pattern that I usually use, which came from a back issue of Burda magazine, but you can use any classic t-shirt pattern. Any of the big name companies should have at least one suitable pattern you can use (this one from Kwik Sew looks pretty good). Now, I like to trace all of my patterns onto sew-in Vilene or tracing paper, so that I can make any fitting adjustments without having to stab into the pattern. It's probably a good idea in this case, because you need to cut in a shoulder yoke.
Why, you ask? A problem I have found is that when you place the front of a child's t-shirt pattern on an adult tee, sometimes you have to move the pattern piece down in order to get the shoulders of the child's pattern out of the way of the t-shirt's neckline. This makes the shirt's graphics sit up way too high. Like this:
See what I mean? If I cut it like this, it would certainly look a bit crap, to my mind, anyway. Oh, I am a pedantic thing. Such is the joy of being me. We need to manipulate the pattern to get it to work to our advantage. So this is what we do.
Take the front piece of your (traced) child's shirt pattern and measure about 4cm from the shoulder and mark at the neck edge. Then measure about half way down the armhole and mark with chalk. Now, draw a line connecting the marks.
Cut along the line.
If your t-shirt has a graphic on the back as well, the same thing can be done to the back pattern piece, if you need it. And, yep. That's it. Now, your pattern piece will sit more squarely over the t-shirt graphic.
First of all, unpick the t-shirt's ribbed neckline. This is by far the most tedious bit, because they are overlocked on. You will be using this ribbing for your new shirt so try not to shred it. But it is boring and fiddly. I usually do my unpicking while watching the daily re-runs of Roseanne, because I've seen them a hundred times before. But despite that, she still makes me laugh hard. Probably not a good thing to be doing when you have a stitch ripper in your hand, but I haven't injured myself yet *crosses fingers*.
Next, cut along all the seams of your t-shirt. Up the side seams, around where the sleeves attach to the body, and the shoulder seams. Once you've separated the sleeves, cut along their seams. Cool. Now you have four flat pieces: a back, a front and two sleeves.
Pin your back and front pattern pieces to the corresponding t-shirt pieces and cut. If your shirt is big enough, you can cut the shoulder yokes from the bottom of the shirt. I managed to fit my yoke pieces on the shoulders of the original shirt. If there's not enough fabric, you may have to check your stash to see if you have some matching jersey fabric. It's probably a good idea to buy 30 or 40 centimetres of jersey to keep just in case you need it. Or, use a contrasting colour (this is a great idea if your re-inventing a masculine design for a girl: you can use pink or some other girly colour or print). If you're really desperate, your partner or friend or child probably has a t-shirt scrunched in the back of a drawer that he or she won't miss. Be sneaky.
I incorporate the t-shirt's original sleeve hem into my new shirt, because it's something less I have to do. Check your pattern instructions to find out what the hem allowance is. If it's, say, three centimetres, fold up three centimetres on your pattern's sleeve opening and fold. Place the fold you just made on the fabric sleeves edge and hey! Instant hem. Cut away!
Using a stretch stitch (the pattern instructions will tell you), attach your fabric shoulder yokes to your fabric front, and then treat as one piece. Again, my finicky and sophistic nature means I like to topstitch mine on the right side with a straight stitch. I like the finish it gives, but it's totally optional.
Now attach the ribbing back onto the neck. Again, use your pattern's instructions to guide you. I have long since lost my instructions, but have the absolute best method is outlined in this tutorial. Try it, it's easy and looks reeeeeeeal professional! (But make sure you trim away the seam allowance on the neckline before proceeding, otherwise, besides your t-shirt looking all weird, it will most likely turn your face blue.)
And again with the top-stitching OCD.
And to celebrate the end of this tutorial, it's time to channel the late, great Michael Hutchence.
Or perhaps not. Happy making!