Sharpie Knife

Why I Like It

There’s a design elegance to objects that completely disguise their function, and the Sharpie Knife nails it. At a glance — and even in-hand — it reads as a standard permanent marker. The cap, the body, the proportions are all faithful to the real thing. What’s inside is a functional blade that deploys cleanly and locks in place. It’s the kind of print that makes people do a double-take when they realize what they’re holding.

The practical EDC case is straightforward: it rides in a shirt pocket, pen slot, or pencil pouch without drawing attention. For travel, creative professionals, or anyone who wants a backup blade that doesn’t telegraph itself, this delivers. That said — know your local laws before you carry. Concealed blade regulations vary significantly by jurisdiction, and “disguised as something else” can complicate legal classification in some places. Carry smart.

Print quality matters here both aesthetically and functionally. Use PETG or ABS at 40% infill — you need the body rigid enough to resist torque when the blade is engaged. Layer lines on the exterior will show, so a light sand and paint finish dramatically improves the disguise. The fit on the blade insert should be snug; if it rattles, scale the receiver cavity down by 0.5% and reprint that section only.

What Filament Should You Use?

Here’s a quick breakdown of the three most common filaments for EDC gear so you can pick the right one for your setup:

TL;DR: Use PETG for most EDC prints — easy to work with and tough enough. Use ASA if the piece will live outdoors or in direct sunlight. Use ABS if you need maximum rigidity and heat resistance and have an enclosure on your printer.