QuiltE

Keep your zig-zag in a long and wide stitch and you can avoid that.
You just need to have it gently attached, as it would be with your whip stitches.

Snooze2978

Don't know about the fluffy type batting but on W & N as well as 80/20 type batting, I use the batting tape you can get in rolls of 10yd, 15yd and 100yds. I bought a ton of it awhile back and have gone thru 2-3 rolls already. I piece most all my scraps of batting if a decent size. Smaller pieces I keep for hot pads or testing out a quilting pattern. With the tape you just butt the two pieces next to each other and iron the tape over it. I haven't found that I have to add the tape to both sides either as the tape seems to hold well for me.

cpcarolyn

I have used a product called "Heat Press Batting Togeather". It is a 1 1/2 wide cloth tape. Works great.

maviskw

This kind of thing makes wonderful pillow stuffing. Salvation Army, Goodwill, Food Pantries and such would like to have them. There are people who don't have a pillow to sleep on. And they are so easy to make.

IBQUILTIN

Like Dunster, I hand stitch the two together after overlapping a little and cutting through both layers. Then I ladder stitch the two loosely

running1

I overlap my two pieces and then use the rotary cutter to cut through both... but I do a long, easy curvy cut. Then I zig-zag the two together with a wide and long zig-zag. No problems and it really doesn't take long at all...

cathyvv

I use the batting tape now. It's much easier than trying to sew it together. Never thought about using pellon to join small pieces, but that's a good idea.

liese

I overlap the pieces by about half an inch and then zig zag

DOTTYMO

Mom-6 I always hand stitch together no matter size of quilt or piece. Why? Because I have never found a flat methods using the zigzag. Sometimes instead of straight I have made a wave shape so as not to have all joined in same place. I made a double wedding ring in sections and joined in curves as I was doing a kind of quilt as you go my way.
I have also found that since I use 505 spray, other makes also available I do a quick spray over before placing together.

mom-6

What I ended up doing was take a strip of lightweight white fabric the same width as my sashing and stitch down each edge. Then placed that along one of the sashing strips so not obvious. Felt like that would hold more securely if the kiddos ended up using it as a doll quilt. And didn't have to figure out how not to compress the batting where it was stitched.