>>1209
So, I just finished (sort of) a DIY onsie made out of an old t shirt and a pair of underwear. A basic list of steps follows.
Things you need:
A) a T shirt, preferably stretchy and sort of tight fitting, but not uncomfortably so
B) a pair of underwear
C) Some velcro straps or other fastener of some sort, ie snaps, etc
D) safety pins
E) needle and thread and/or ability to use a sewing machine, but can be done all manual
1) take underwear and cut along the narrow part that goes between your legs so that it is cut in half.
2) sew along both sides of this cut so that the fabric doesnt get unraveled or anything, also to hold the two flaps/layers together.
3) take old T shirt and underwear and use a bunch of safety pins to roughly pin them together, not worrying too much about position at this point.
4) put it on like a regular shirt, then see how it fits with where you put the pins. Try stretching the two flaps on the underwear together like it will be when its done to see how well it fits, how snug, etc. The big thing I adjusted here was how far down to pin the T shirt on the underwear. I decided to use the entire shirt instead of cutting off part of it and sewing the new bottom of the shirt to the underwear waist band both because I thought that it would look better this way, and because having that cut in the fabric where the hem was before might weaken it, and I really didnt want to sew all the way around it if I could avoid it.
4.5) A couple of things that I learned in hindsight: First, if the T shirt reaches below the waist band of the underwear, especially if its more than an inch or two, consider starting off with two layers of safety pins, one on the bottom of the shirt pinned below the waist band of the underwear, and the other at the waist band of the underwear pinned to somewhere above the bottom of the T shirt hem. This makes sewing easier later on, as otherwise you keep getting folds of fabric hanging down and getting in the way on the inside. The second big thing I learned is to draw a line in addition to the safety pins along where you want to have the stitching go. This makes it MUCH easier to follow a consistent curve all the way around in my opinion. Draw this line while you are still wearing it so you know the line is where you want it. (use a washable marker or maybe some masking tape?)
5) Now comes the long part. Just sew around the line/between the safety pins! I did this by hand with a needle and thread because I don't have any experience with a sewing machine and I wanted to be discreet while making it, so I suppose this wouldnt take too long if you were using one.
5.5) If you have a second ring of safety pins, sew along that row as well
6) Next, take some velcro strips/straps and sew them along the flaps of the underwear. This will make it easy to put it on and off. Other ideas might work too, velcro just seems the easiest. Right now I am wearing mine with temporary tape holding it together, but snaps or even adhesive velcro would work fine too.
Your done!
I finished mine just today, and it turned out reasonably well all things considered. I think I am still going to just buy a onesie to be honest though. All things considered, it feels pretty good!