Edyta Sitar wrote about this in her new book Seasonal Silhouettes.
Edyta said she uses these fusible webs most often with raw edge applique:
1. HeatnBond Light, which she says "gives a clean, sharp raw edge", but warns against over-pressing it, which can make quilting more difficult.
2. SteamASeam 2, which she says can be repositioned easily, but notes that over time it gives the edges a medium fray.
3. WonderUnder 805. She finds that edges fray the most with this one, but it is easy to trace on and quilt through. '
She says to experiment with different brands and weights.
I didn't know fusible web products were all so different.
Here are a few things I have learned.
Use a fabric with a tight weave. Batiks as a rule, have a tighter weave and tend to fray less than a lot of printed fabrics. (The exception to thi rule would be some cheap loosely woven batiks at chain stores that would be awful to work with.)
Some fusible webs come with instructions to prewash fabrics to remove any finishes on the fabric that might prevent a good bond.
Don't use fabric softener.
Be careful not to overpress the fusible and applique too long, especially with an iron that is too hot. This causes the applique to feel stiff and hard, and makes it harder to quilt through.
If I am raw-edge appliqueing and I have a fabric that wants to fray, I trim off the little tips of thread that stick out, and put a thin coat of June Taylors Fray-Block on the cut edge, let it dry thoroughly and then machine applique it down. I only put it on the cut edge. I like this brand, because it dries soft and flexible and dries clear with no discoloration.
Judy Austin