Originally Posted by
QuiltE
Is fusible batting, a permanent fuse?
Or does the fuse disappear with washing, so that it becomes like regular batting?
Per Hobbs Batting's website, the fusible is water soluble
Hobbs Heirloom Fusible Batting, so it washes away when you wash the finished quilt. Lots of other important information on that page.
Note that it's apparently fusible on both sides, so you'd want all 3 layers stacked before you start pressing to activate the adhesive.
Hobbs advises quilting no more than 4" apart.
ETA - and you must use a hot, dry iron. If you use steam, it won't stick.