How to Bridge a Stencil

I first started making stencils because I had a brand new laser cutter, and I wanted an excuse to watch the laser cut up a bunch of card stock. Without knowing too much about stencils, I used the ‘trace’ function of Adobe Illustrator to separate an image into light and dark. When I fed the resulting SVGs to the laser, I was surprised that the cut out parts kind of looked like the original image.

I sprayed that stencil with black spray paint, and was surprised that it was recognizable. But some critical light parts of the image were now dark. That was because, wherever the pattern of the image made an island, that island was cut out, and the critical area was not being masked from the spray paint. It made my faces look like hollowed-out skulls with no eyes. But I was onto something.

If those masking areas could be bridged back to the rest of the material so that the whole thing held together during painting, I would have a true stencil.

Illustration: Bullseye stencil

To paint a bullseye target, you can do it one of two ways: you can paint alternating red and white disks of decreasing size, like this:

  • paint big red disk
  • paint slightly smaller white disk
  • paint slightly smaller red disk
  • paint slightly smaller white disk
  • paint slightly smaller red disk
  • paint slightly smaller white disk
  • paint slightly smaller red disk

But most of us would choose just to paint a white background and then paint a single red stencil, that consists of multiple concentric *rings* (rather than painting red-over-white, white-over-red, multiple times).

The tough part is making that stencil of concentric rings that holds together. You see, if we just send a vector file to a cutter that says ‘cut concentric rings’, then we’re going to get a bunch of unconnected concentric rings (aka, garbage). What we need to do is bridge those concentric rings so that they properly mask off the area that should remain white when we paint red.

Let’s bridge the bullseye image by hand, in a few different ways.

Add bridges in a drawing program, like Procreate

When you make your bridges in a drawing program, you’re probably going to use a raster editing program like Photoshop, Canva, Gimp or Procreate. In this case, you’re just drawing the bridges in on top of the color. Later on, some other tool will vectorize this for you, and when that happens your bridges will be part of the vector art.

bridging a raster file in procreate on ipad
bridging a raster file in procreate on ipad

Adding bridges to a vector illustration

If your stencil subject is already vectorized, and you just want to add bridges to a layer, then you can do that in vector illustration programs like Illustrator or Inkscape.

Adding bridges in Illustrator

In Illustrator, follow these steps:

  • Select the outline you want to bridge
  • Select the Eraser tool
  • Open the options for the Eraser tool to set the width of the tool (to match the width of the bridge you want to make)
  • Hold down the Shift key, and click and drag across your shape
  • When you release the mouse button, the cut out shape will smooth slightly
bridging a vector file in illustrator
bridging a vector file in illustrator

Holding down the Shift Key restricts your eraser from moving in 45-degree increments around the compass, which makes for cleaner bridges. If you need more freedom, you can leave off the Shift Key, and just make your cuts faster (so that they are smoother).

Adding bridges in Inkscape

In Inkscape, follow these steps:

  • Select the Eraser tool
  • (optionally) change the width of the Eraser
  • Click and drag across the shape where you want the bridge to appear
bridging a vector file in inkscape
bridging a vector file in inkscape

Adding bridges in Cricut Design Space

Follow these steps:

  • Upload your SVG to Design Space and import it into your project
  • Select ‘Shapes’, and click on the Rectangle shape
  • Resize the rectangle so that it’s the right length and width for a bridge
  • Drag the rectangle bridge to the place on your shape where you want the bridge
  • Select both the rectangle bridge shape *and* your stencil shape
  • Select ‘Combine’ and choose ‘Subtract’
  • Your rectangular bridge shape will disappear, leaving a gap in the stencil shape
  • Repeat as often as needed
bridging a vector file upload in cricut design space
bridging a vector file upload in cricut design space

You can also use these two Hints:

  • By copying and pasting your rectangular bridge shape, you can avoid creating it multiple times
  • If you want to place all your bridges at once: you can place multiple bridges, then select them all (and the stencil shape) and do the ‘Combine/Subtract’ action just once

Bay Stencil and Bridges

If any of this looks tedious to you, well, that’s why we built Bay Stencil.

bridging is automatic with Bay Stencil
bridging is automatic with Bay Stencil

Bay Stencil not only separates your artwork into colors and gives you multiple options to choose from, it also bridges the SVGs for you.

Bay Stencil offers several bridging options:

  • no bridges
  • one bridge per island
  • fewer bridges
  • stable bridging

‘Fewer bridges’ is the default; it’s a pretty good compromise since the resulting stencils are pretty stable without being crisscrossed by a lot of bridges. If you only want to cut once, though, you might try the ‘stable’ setting–which may have too many bridges for you–but it’s a lot easier to remove extra bridges than it is to add back bridges that you wish you had.

‘Fewer bridges’ works most of the time, but sometimes there might be a floppy piece or two.

One bridge per island is recommended when you just don’t want to lose any pieces of the stencil, but you don’t care how floppy it is and you’re going to manually move the connected pieces where they belong before painting.

bullseye stencil with arrows in the center
bullseye stencil with arrows in the center

And of course, the bullseye is just an example of the bridging exercise posed to stencilers. Other images have the same issues. But if you’re looking for a great, bullseye stencil, you can download the free one here.