I didn't forget about my tutorial, I was on vacation!
I've found that the slip stitch is working for the sleeves of my wildlife tshirt but not the hem at the bottom. Right now, I'm going to recommend doing a top-stitch kind of hem. You can see it but it will be better for a knit because it's easier to do a stretch stitch with a machine. Tell us how you did it!!
I started with a biiig t-shirt and a little tshirt (the small one is the size I want my new one to be). I lined up the necks of the shirts which were roughly the same size and then put pins all around the little shirt (in blue). Doing it this way might not give you long enough sleeves! It really depends on the length from the neck to the start of the sleeve (the original shirts shoulder).
I cut off the sleeves. I wasn't sure how much extra I would need for a hem. If you are going to do it this way, you probably want to cut off the sleeve right at the seam so you don't see it.
I cut out the shape of the pins. Remember to leave about an inch for seam allowance!! My tshirt was all stretched so I left didn't cut off the bottom at this point. I left the bottom hem until the very end when i could try it on. I also left the pins in so I know where to sew/serge.
When I cut the extra off around the sleeves, I left lots of extra seam allowance just in case. I also left the pins in. The orange line is the original sleeve seam.
Here is it, ready to be sewn! (except the bottom which is really long at the moment)
This part is easy. Turn the shirt inside out and sew along the lines of the pins (take them out as you go along). When you get to the armpit, put the needle down, lift up the foot and turn the shirt, then start sewing again. Here's mine:
I just top stitched the edge of the sleeves.
I think I'll sew some lace around the top of mine...
Now try it for yourself!!