The thinner battings are sooo much easier to piece. Warm and natural is easy just but the edges to gether and zig zag. Fat bat ... the really high loft is a bit harder. I typically just hand baste them by butting the edges. On the fat bats the presser foot always seems to find its way into the batting. I have tried the paper over the top to prevent the foot from digging into the batting , but was not happy with the results. The stitch compressed the batting too much. Hand basting the Fat battings did not take too long since you can use large sloppy stitches since no one will ever see them.

I've used this tape it is Wonderful! but I think expensive.(my opinion)
It is called "HEAT PRESS batting together" and includes 10 yards of fusible 1 1/2" wide cloth tape. Their email is : www.heatpressbattingtogether.com or they also have number on their bag. The one I bought was from a LQS and paid $8.99 for it.

I must be in the minority. I overlap my Warm and Natural battings approx 1/4" and do a serpentine stitch. Yes it makes a slight bump in my quilts but not enough to fret over. No one's ever mentioned feeling it while sleeping under the quilts. I don't make quilts to submit for judging,. But if I did, I admit I would just butt the edges up like everyone else. My way is just easier for me and, admittedly, a habit.

wow - thanks for the tip! I also use every bit of batting possible....and have had to join several pieces together....This product will save me lots of hand sewing the pieces together....!

I hand sew the batting edges together and I find it is really fast and I have never had a problem. With the cost of batting here it sure saves money to use every piece of it.

to get edges that fit together exactly, overlap the two pieces a little and rotary cut down the double thickness - get rid of the two "leftover" scrappy pieces, butt the big pieces together and zig zag them together. Trying to butt together edges that are not cut this way can lead to a distorted seam that might be noticable. The cut you make thru the double thickness doesn't have to be straight as long as you cut both pieces the same they'll fit together.

I used this tape for the first time this week. I like it. It holds good. It did get my iron a little sticky. A used laundry softener sheet cleaned it right up, though.

Love this idea. Just ordered some.

I have some tape, it works great but it is expensive and you have to be careful to not have your iron too hot especially if you use the less expensive batting. I used a pressing cloth so I didn't melt the polyester.
you can get it on ebay

I use heat press batting tape. As an added secure measure, and since I don't trust that it will stay ironed onto the batting, I turn over the batting and ladder stitch the seams by hand. I won't put the batting under the needle without fabric on each side. When ironing (press, don't actually move your iron back and forth) you are butting the seams up. When the batting is turned over, the seams are perfectly set against each other, no layering, no bunching. Done this to many many quilts and after washing-no problems what so ever. I buy the large rolls of batting, so when I make the quilts and they are larger than the width of the roll of batting, I place the straight edge of the batting one third of the way in from one edge, and then butt up the other piece. You want to trim the raw edges around the quilt anyway, so why use up the good straight edge you already have. I never have a seam going down the center.