The interweb is vast, so I am sure there is already something like this out there. I thought of making a bib using a bandanna a couple of months ago. Because of my craft-supply hoarding, I already had everything, except for the bandannas, which I purchased in a two-pack from Target for $4.
Here's what you'll need:
fabric for back
Typical sewing supplies: scissors, thread, sewing machines, pins etc.
1. Cut the bandanna to your desired size. I held up my bandanna to my son's neck and just haphazardly measured. It wasn't perfect (FYI - bandannas are not perfect, nor square), but I think they measured about 11" on each side. I used a rotary cutter, which made cutting through all 4 bandannas a breeze. Each bandanna yields two bibs.
** I recommend to cut the area around the neck into more of a scoop, instead of leaving it straight. I realized this the hard way.... If left straight, it tends to bunch up a lot around the neck and will likely come up and cover your baby's chin.. not idea!**
3. Pin the pieces together. I layered the pieces like so (top to bottom): bandanna material, backing material, batting. Pin the right sides (or the sides of the material you want to show on the outside when finished) together, because you will be pulling this inside out.
6. Iron the edges. Ironing makes the seams cleaner.
7. Fold the 4" inch open area in, pin, and sew around the parameter of the bib. I folded the edges in about 1/4" and then pinned them in place (see the pic below). I again used 1/4" seam allowance when sewing around the edges.
8. Pin the Velcro in place. Use the loop side (the rougher kind of Velcro) away from where it will be worn. That way it won't irritate your little one's skin. Sew into place.
And boom! Finished product! I hope that all makes sense :) I was doing multiple bibs so it took me a bit longer, but this is easily a nap-time project. Again, not perfect, but I am perfectly happy with the way it turned out.
And here's my little guy wearing his new bib. I think he looks just adorable! (look close and you can see all of his teeth i.e. the reason he needed new bibs in the first place. Dude is a drool-machine!)