This is what I do... I am glad that kheliwud responded I was starting to wonder if I was the only one

When you iron the fusible, does it flatten the batting?

I've had problems with the tape so just went back to zig zagging, which works fine. Piecing batting works great as long as you sew the pieces together, as with machine zig zag or whipstitch by hand. I received a doll quilt in a swap and she must have just laid two pieces of batting side by side, thinking the quilting would be enough to hold them in place. It wasn't... after the first washing, the batting seperated. Be sure you SEW your batting together, one way or another.

I've always just zig zagged, and never had a problem. I can see though if you have a white fabric backing you might want to be careful.

Take one day. Slap on the good old walking foot. Dig out all your pieces. Zig-zag away and you will be AMAZED at how many good sized batts you get at the end of that day! Just make sure you use a thread that closely matches the color of the batting.

I've zigzagged batting pieces together with no problems. No ridges noticed on the quilted articles at all.

I have learned about putting my unused batting together , Thank you everyone

I have been piecing W&N batting for years and I am not aware of any problems with my method of cutting 2 straight edges, butting them together and then using a wide zig zag stitch to join them. Sometimes those pieced battings have enabled me to finish sandwiching a quilt rather than opening up another bag of W&N.

I zig zag my batting.

I whip stitch pieces together, have never noticed any issues once it's quilted. I do use pieces of the same battings when I "make" one- good use of leftovers