The bag maker's structure guide
Interfacing & Stabilizer for Bag Making: Choose the Right Structure
Want a soft, quilted bag or one that stands on its own? The layer underneath your fabric makes a big difference.
It's easy to spend ages choosing the perfect exterior fabric and then get stuck on the interfacing. Do you need Sew Woven, fleece, foam, or Decovil? The answer depends on your fabric, the size of your bag, and how much structure you want.
Start with your pattern's recommendations, then use this guide to understand what each material contributes. You can also combine them: woven interfacing can support quilting cotton while foam or Decovil gives selected pieces more shape.
Woven interfacing supports fabric while keeping it flexible. Fleece and batting add softness and cushion. Foam gives large panels light, padded structure. Decovil and Peltex create firmer shape, especially in bases and flaps.
Compare your options at a glance
| Material | Feel | Best use |
|---|---|---|
| SF101 / Sew Woven | Flexible | Supporting quilting cotton or subtle one-way stretch |
| 987F Fusible Fleece | Soft and padded | Softly structured bags and pouches |
| Batting | Lofty | Quilted panels and texture |
| 525 Decovil Light | Firm but flexible | Structured small and medium bags |
| 523 Decovil Light Sew-In | Firm but flexible | Projects where you prefer not to fuse |
| 526 Decovil Heavy | Very firm | Bag bases and structured flaps |
| Peltex 71F | Rigid | Very firm bases and panels |
| FF78F1 / FF77 Flex-Foam | Supportive and cushioned | Large totes, backpacks, and travel bags |
| Décor-Bond | Crisp | Organizers and firm panels without foam |
| Tear-away | Temporary | Embroidery and stitching support |
| Callie Del® | Firm with some flexibility | Everyday bags and crisp panels |
For flexible support and soft padding
SF101 Shape-Flex or Sew Woven™
These lightweight woven fusible interfacings support fabric without making it stiff. They're my starting point for quilting cotton exteriors and linings. Woven interfacing generally isn't required for vinyl, cork, or waterproof canvas, but it can help when a faux leather, faux suede, or vinyl has a subtle one-way stretch. Test fusing on a scrap first and use heat appropriate for your fabric.
Choose it for: Quilting cotton or fabric that needs a little stability. Keep in mind: It won't make a bag stand up by itself.
Pellon 987F Fusible Fleece
Fusible fleece adds a soft layer of padding and a little body. It works well when you want a bag or pouch to feel cushioned rather than crisp.
Choose it for: Soft bags, quilted panels, and pouches. Keep in mind: It isn't a substitute for a firm base or heavily structured panel.
Batting
Reach for batting when you want visible quilting, loft, and a softer padded look. It's lovely for quilted bags and pouches, but it won't give you the firmness of foam, Decovil, or Peltex.
For bags that need more shape
525 Decovil Light
Decovil Light gives bags a smooth, leather-like feel and moderate structure while still allowing some flexibility. It's a favorite for small to medium structured bags, wallets, and panels you want to hold their shape.
Choose it for: A shaped bag without a rigid feel. Keep in mind: On a large bag, it can add more weight than foam; keep it out of seam allowances when your pattern directs you to.
523 Decovil Light Sew-In
Prefer not to fuse your stabilizer? The sew-in version provides a similar leather-like support without an adhesive layer. Secure it as directed by your pattern so it stays in place during construction.
526 Decovil Heavy
Decovil Heavy is the firmer sibling. Use it where you need a base, flap, or selected panel to stay put. It's more difficult to turn through tight openings or sew through in thick seams, so placement matters.
Choose it for: Firm bag bases, structured flaps, and reinforcement. Keep in mind: Leave it out of seam allowances unless your pattern specifies otherwise.
Peltex 71F One-Sided Fusible
Peltex is an ultra-firm choice for a bag base or rigid panel. It offers strong support, but it isn't the right feel for an area that needs to bend. Allow time to fuse it properly and avoid bulky seam allowances.
For larger bags: foam
Foam can support a large panel without making the whole bag feel heavy. It also adds padding, which is useful in backpacks, travel bags, diaper bags, and laptop sleeves.
FF78F1 Flex-Foam, One-Sided Fusible
This foam adds cushioned structure and bonds to your fabric. It's helpful when you want large panels to hold their shape without adding the weight of a dense stabilizer. Fuse carefully to avoid wrinkles, and follow your pattern's instructions for trimming foam from seam allowances.
FF77 Flex-Foam, Sew-In
Choose sew-in foam when you want that supportive, cushioned feel without fusing. Secure it well so it doesn't shift while sewing. If your pattern includes foam in the seam allowance, a zigzag stitch or serger along the edge can compress the foam and reduce bulk.
Specialty support
Décor-Bond
Décor-Bond gives panels a crisp, firm feel without foam's thickness. Try it for organizers or craft-style panels when you want a clean edge and a flatter finish.
Tear-Away Stabilizer
Tear-away provides temporary support while you stitch, especially for machine embroidery or dense decorative sewing. Remove it after stitching; it isn't meant to provide the finished bag's structure.
Callie Del®
Callie Del® is a fusible, nonwoven option for a crisp, supported finish with some flexibility. It's useful in everyday bags and panels where you want structure without the thickness of foam.
See the materials in action
Want to see how the options compare? In the video below, I walk through several interfacing and stabilizer choices and explain where I use them in bag making.
