I used to follow a tutorial to the letter and still end up with a slouchy bag or puffy corners. Nine times out of ten it was the interfacing. This post is a quick, honest guide you can skim, with just enough detail to fix the usual problems and choose the right stabiliser next time.
The real problem
You sew carefully and the bag still looks a bit sad. Signs to watch for: a body that collapses when you wanted shape, a wobbly top edge, corners that puff instead of turning crisp, handles that feel flimsy, a base that sags once you add your purse, or a bag that turns heavy and cardboard stiff. Most of this comes down to the wrong interfacing or the right one applied in the wrong way.
Why interfacing changes everything
- Shape - the right stabiliser makes sides stand up or drape softly, on purpose.
- Feel - fleece gives cushioned softness, foam gives a clean boxy feel, Decovil gives firm structure.
- Durability - handles keep their strength and edges topstitch neatly.
- Easier sewing - seams turn cleaner when bulk is planned and corners press flatter.
Quick answer: start here
Pick the feel you want, then try one of these.
Soft but supported
- Quilting cotton - Vlieseline G700 or Pellon SF101 on the outer, plus H630 or 987F on the lining.
Stand up structure
- Any fabric - Style‑Vil or Flex‑Foam FF77 as sew in for the body, plus G700 or SF101 on the lining. Trim foam 1 cm (3⁄8 in) from seams.
Vlieseline and Pellon equivalents - teaser
| Purpose | Vlieseline (UK/EU) | Pellon (US) | Use case |
|---|---|---|---|
| Woven fusible, medium | G700 | SF101 Shape Flex | Everyday strength for cotton and canvas |
| Fusible fleece, low loft | H630 | 987F | Adds soft body to lining or outer |
Get the full chart in the PDF. It includes S320 and 809 for crisp projects, Style Vil and Flex Foam, and Decovil I or Light with Peltex 71F.
Simple fusing checklist
- Pre press fabric so moisture is out and fibres relax.
- Cut fusible 2 to 3 mm inside the stitch line so seams turn cleanly.
- Use a damp press cloth for G700, H630, S320 and for Decovil I or Light. Press without sliding and let it cool flat. Do not use steam on foam.
- Lengthen stitch to 3.0 to 3.5 mm when sewing through foam and trim foam out of the seam allowance.
Quick FAQs
What is the UK equivalent of Pellon SF101
Vlieseline G700. Both are woven cotton fusibles for light to medium fabrics.
Do I need foam or fusible fleece
Foam makes bags stand up. Fleece adds soft body. Use foam for structured totes, fleece for softer pouches.
Can I fuse Decovil with steam
Use a damp press cloth and hold the iron still for a few seconds. Cool flat. Do not steam foam.
If you want the full version with all the recipes, the complete chart and printable references, you can download the Download the full Interfacing Guide with complete chart and printable checklist.
If you're browsing for ideas, you can take a look at our one-of-a-kind tote bags made with rescued fabrics.
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