If you are asking if the Raw Edge Applique method (Wonder Under on the back, fuse it down, zigzag around the edges) will hold up in the wash, absolutely yes. I did my second daughter's baby quilt with this method and it's now 3 years old, been washed countless times on hot and dried in the dryer on normal heat and it's totally fine. Remember that Raw Edge will fray a tiny bit around the edges of the appliques, but with the zigzag, this is very minimal. I used a small zigzag, and a shorter stitch length but definitely nowhere near looking like a satin stitch. It's still very clearly a zigzag. I love Raw Edge because it's much faster for me, and now that I have a machine that does blanket stitching, I do find that the blanket stitch doesn't require any kind of stabilizer to avoid puckering, but I think it will fray a little more than the zigzag. If you care about the zigzag pulling the background fabric in towards the applique, you can back it with a water soluble adhesive stabilizer (Solvy makes one that comes on a roll) though honestly, once you wash the quilt, you wouldn't even notice it. Just depends on how much it would bother you
