Yep, I did use a dry iron. I did let it sit longer the second time and I did iron the front and back. It did seem to be sticking at first but then just let go. I live by the water so perhaps the moisture in the air has damaged the glue. Now I am holding a steamy iron over the bocks hoping they will go back in shape as I safety pin it together. I have never free motioned a pinned quilt( this is my 3rd quilt) so it should be interesting.
I have some pieces left that I will try to use in place mats just to see if I can figure out what went wrong. I will definitely stick to spray basting after this.

I have had a similar experience with fusible batting... it will stick in some places and not others. I only use it for mug rugs and other small items because it's really frustrating.

I've used it for smaller projects and I don't like it. I never had any success with it sticking. I have better luck with Elmer's glue.

I'll jump on the bandwagon here. I have never, regardless of application, had any luck with fusible anything. LOL, could it be the operator??

I'm with you on this ... seems like I have issues with everything I try ! But that's o.k., keeps my old brain working as I work out the messes I make :D.

While I'm not familiar with Hobbs 80/20 fusible batting, I can only comment that I use fusible fleece/batting for small projects, purses, tote bags, wall hangings, placemats and table runners and it has always worked well. Sometimes though I will need to press a second time for the fusible material to attach itself to the quilt.

Largest I've used is baby quilt and it did start to come apart before I finished FMQ. Spray basted worked better but I was too messy with it!
Would add that I've gotten into trouble with bias edges on a quilt--particularly larger blocks,so now I starch before cutting those and run a seam on outside edge before putting on the frame--saves headaches.