This tutorial is going to give you directions for a tube top like this (stretchy, knit fabric with no seams) along with ideas for adaptations:
You can adapt it to work for your old tube tops or your thrift store finds. Just make sure if you're sewing a knit fabric that you use a ballpoint needle in your sewing machine.
Here's a "before" shot of me wearing it 7 years ago:
First, put it on your little model and using clothespins, clip it to the right size. Don't worry about whether it's done neatly, you're just trying to figure out what the finished length and width should be.
You can also use a store-bought tunic in the correct size to see what the finished measurements should be.
Now lay it out flat to measure the length and width. Right down the numbers somewhere so you don't forget later, then unclip it. We're going to work on getting the width right first, then the length.
(Little Sweets wears 2T or 3T and the finished measurements for her were 16" long and 9" wide.)
Now calculate how many inches you need to cut out of it to get it to the right finished width. Since I wanted to it to measure 9" across when finished and it started out at 17", I cut out 7". I included a generous 1" buffer, just in case my measurements were off (better to cut out too little than too much!).
Like I said, my tube top was seamless, so I got to pick where I wanted the seam to be. I decided it would be in the middle of the back since that would be easier than doing two down the sides. So I cut out the extra 7" from the middle. I used pins to mark where I was going to cut (my tailor's chalk wouldn't write on this fabric or I would've just marked it that way). I hope the picture explains this better:
(If you already have two seams down the sides, you can cut those and the extra material out from the sides to get the right width--in this case it would've been 3.5" from each side.)
Here's another picture to explain this part. On the left you can see where I pinned to get rid of those extra 7". I decided to sew down those lines before cutting because I didn't want the ruching to unravel. On the right, you can see what it looked like after it was sewn:
Then cut out the extra fabric and save it so you can make straps later.
Now, fold it in half lengthwise with right sides together and raw edges aligned. Pin in place and sew to create the seam in the back.
Now it's the right width and we need to work on the length. My tube top had an empire waist so I cut it into two pieces right at the bottom of the ruching. (If your tube top doesn't have details like this empire waist and ruching, the easiest way to do this part would be to cut off some fabric from the bottom and do a simple hem--and you'd be done!)
I wanted the ruched part to be 5" long to get the correct finished length of 16", so I measured and marked with a pin where to cut and sew (remember your seam allowance.)
Now you can sew along the marked line.
Oops! I realized after I sewed it that I did it wrong. Time for the seam ripper (it gets a lot of use in my house).
What did I do wrong? I sewed it like I usually sew quilting fabric, making sure not to pull on it. But this fabric is stretchy and I needed to pull it while sewing to make sure that it would stay stretchy. Here's the right way... see how it's pulled taut? That will allow it to stretch after it's sewn.
(I added this extra step of sewing along the cut edge before I sewed the two parts together to make sure that the ruching didn't unravel. If you know how to sew and your fabric is just a regular cotton/knit, you can skip this extra step.)
Okay now it's time to put the top and bottom together. This next photo shows how to start putting it together, with ride sides facing and the seams aligned:
Tuck the top part all the way into the bottom part and align the cut edges. Since the top is clearly narrower than the bottom, you'll need to do some more stretching as you sew. To do that, first pin where the seams are aligned (in the back) like you see in the next photo. Then pin on the other side (the front). Then stretch it evenly and add a pin on each side. This will show you how much you need to stretch as you sew.
Hope that makes sense. If not, keep your seam ripper handy! Nothing wrong with trial and error when you're sewing. =) When the two parts are sewn together it should look like this and it should be the right length and width:
Go back to the piece you cut out and cut some pieces long enough for straps. You may need to measure your model (or correctly-sized tunic) for this. I chose to gather the ends of each strap to add a little flair so I cut the straps much wider than they needed to be. See Step 2 of this tutorial to learn how to gather if you've never tried it before--it's very easy!
Put the tunic on your model and pin the straps where they should be... Little Sweets sits motionless when the TV is on so I knew that would be the perfect way to get this part done. Just be careful with the sharp pins, especially when you take it off! I liked the idea of cris-crossing the straps since I had long enough pieces of fabric left over.
Flip the tunic inside-out and carefully move the pins to the other side so you can see them as you sew. This photo shows it before I moved the pins to the other side:
Sew above the gathered seam (I sewed in the ditch where the ruching starts in order to hide the seam), then remove the gathering threads and trim the extra material. And here it is:
All done! Now your favorite tube top (or thrifted find!) can have a second life as a cute toddler tunic.
I love the cris-crossed straps in the back.
With the gathered straps, you can stretch them out to make the straps look more like cap-sleeves than tank top straps too! Looks like Little Sweets likes wearing Mommy's old tube top. I hope your little one likes it, too!