How do I apply fusible interfacing?

Fusible interfacing bonds with heat, pressure and time — and the commonest failure is not enough of all three.

Identify the glue side. It is the one with small shiny dots. Interfacing fused the wrong way up welds itself to the iron, so check before every piece and keep a pressing cloth between the iron and the work as insurance.

Cut it slightly smaller than the fabric piece, trimming it out of the seam allowances on heavy fabric to reduce bulk. On light fabric it can go right to the edge.

Press, do not slide. Set the iron down, hold it for 10 to 15 seconds with real downward pressure, lift, move to an overlapping position, and repeat. Sliding shifts the interfacing and produces bubbles.

Use the right temperature, and steam only if the manufacturer says so. Many fusibles want a dry iron; some want a damp pressing cloth. Test on a scrap.

Let it cool flat. The bond forms as the adhesive cools and sets. Picking the piece up while warm is what makes interfacing lift at the edges later.

Test on a scrap of the actual fabric, every time. Interfacing that is too heavy makes a collar into cardboard, and the only way to judge is to fuse a sample and handle it.

Preshrink it if the garment will be washed — some interfacings shrink and then bubble the fabric after the first wash.

On fabric that cannot take heat — some synthetics, velvet, anything with a pile — use a sew-in interfacing instead.