Chalk this Simplicity 4079 up to lessons learned about interfacing

  This lesson hurt.  I bought this herringbone wool from Canadian vendor Wool House when Sewing Expo came to Atlanta in 2010.  I waited a year to cut into it, and finally decided that it would make a nice addition to my work wardrobe as a dressy vest, especially since silk tie blouses are in this year.  I have even made this vest before, but I made it from a tapestry fabric where interfacing wasn't an issue. 

So hopefully by photographing it here, you will retain a mental picture of my mistake and why you shouldn't skip interfacing with wool herringbone.  I did interface the front flaps, which is all the pattern called for.  But the fabric needs something sturdier under it to keep from looking frumpy.    

The biggest mistake was using flannel on the back to line the rayon lining.  When I made the vest before, the tapestry on the front and sides hung heavier than the lining and made the vest hitch forward.  This time, I added a layer of lightweight flannel to the lining, thinking the back would be heavier and balance out the garment.  But this time, the back was heavier than the front, and the place it really shows is the pointed corners at the vent where the side joins the back. 

So the lesson learned is this:  the front, side, and back pieces' weights should pull at the seams evenly.  If they are not interfaced in a way that balances their weights out, the difference shows up in a wavy seam.