Tutorial: Transforming bloomers into functional panties

If your three-year-old is anything like mine, sooner or later, if she's wearing a dress, everybody will get to see the Care Bears panties she wore that day.  So even though she's potty trained, I tend to still make either fancy knickers to go underneath, or matching ones.  Examine the difference between the patterns and the RTW variety, and the main difference is that RTW panties have a double layer gusset between the legs. 

So if you sew in a knit gusset to keep sensitive areas away from seams, they become functional panties.  My first move was to trace the shape of the RTW gusset.  I did make it a bit wider, because, after all, these are poofy blomers!  Next, I assembled the panties in question, except for the leg elastic. 

My original thought was to sew the crotch seam first and not the side seams, but a bit of fiddling proved to me that for this pair, at least, that wouldn't work.

I cut the gusset from a scrap of knit, and it ended up
looking like this:

After a little cussing at it, I got it centered over the center seam of the panties, and pinned down.  On the right side of the panties, I took my #4 double needle and stitched down on the needle line, locking the raw edges of the knit in place.

After it's sewn down, all that's left to do is add the casings and the elastic. 

If you look closely, you can see the double line of stitching that holds the gusset in place.  Honestly,  I think this might've been easier with, say, Vogue 8060!