A while back a bag pattern called for “foam interfacing” and I had NO IDEA what that was. Luckily, the folks at my local quilt shop DID know! They sold me Annie’s Soft and Stable and it has worked out very well!
The bag above was the one that initially required foam interfacing. I used the foam interfacing again recently, when I made a new version of the Market Tote from Bijou Lovely.
It worked just as well on the larger bag as it had on the smaller one. It gives the bag lots of structure with little weight.
The very BEST part was making handles with foam interfacing rather than the usual turn-the-tube method! I just cut strips of foam interfacing, wrapped them with fabric (turning under the last edge), and sewed three straight lines–one down the middle of the handle to close the fabric and one about 1/4″ from each edge of the handle as decorative top-stitching. It made comfortable, sturdy handles for the bag. Definitely making handles that way in the future!
There are several other brands of foam interfacing, including a couple (from the reliable Pellon company) that are fusible. It also comes in more than one thickness. I haven’t really tried any of the other brands, but this one worked out well.