Stencil bridges: keep the middle of the O
Cut the word "BOARD" out of stencil film and four pieces fall on the floor: the middles of the B (twice), the O, the A and the D. Those pieces are islands, parts of the stencil sheet completely surrounded by cut-away design. With nothing holding them in place, the paint goes straight through where the counters should be.
A bridge is a thin strip of sheet left uncut so the island stays attached. Stencil typefaces are drawn with bridges built in. Everything else needs them added.
How wide should a bridge be?
Wide enough to survive handling and painting, narrow enough that the eye fills the gap. That balance moves with size and technique:
- Small stencils cut from adhesive vinyl, used once: 1–2 mm is often enough, because the vinyl is stuck down before the carrier comes off.
- Reusable mylar stencils that get lifted and washed: 2–3 mm, more for large sizes.
- Spray paint spreads under thin bridges, so wider bridges keep the gap visible. Stippling with a brush can use thinner ones.
Makerfern measures the bridge width in millimetres at your cut size, so the same setting gives the same physical strip whether the stencil is 4 inches or 24.
Where should a bridge go?
The shortest crossing is usually the least visible, and it's the strongest, because a short strip flexes less. On lettering that often means the thinnest part of the stroke: the top or bottom of an O, or the middle of the A's crossbar.
Makerfern places bridges by searching outward from each island for the shortest path through the design to sheet that's already connected. It handles nested islands, like an O inside a ring, by connecting the largest island first and repeating until nothing is floating. The preview outlines each bridge so you can check where it landed.
When to move one by hand: if a bridge crosses a face, an eye or a key detail, open the SVG in Inkscape or Illustrator and move that strip to a less important spot. The shortest path is a good default, not an art director.
Do you always need bridges?
No. If you're cutting adhesive vinyl and weeding it like a decal, you place the islands by hand. The transfer tape holds them in position. Bridges matter when the stencil must be one connected sheet: reusable stencils, freezer-paper stencils ironed onto fabric, and anything you spray.
Common problems
Too many bridges
Distressed textures and photos create dozens of tiny islands. Raise the smallest-piece setting first, which removes islands too small to matter, and the bridge count drops with them.
Bridges that tear
Widen them, or cut from a stiffer material. Makerfern's thin-spot check also flags narrow strips of sheet between cuts, which tear for the same reason.
Try it on your own design
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