March 4, 2026
Description
StopLossBags sells their own replacement caps but they're overpriced and prone to splitting.
Despite the print settings recommended below (and used in the included 3mf project file) with basically 100% infill anywhere that might leak, I couldn't make these seal entirely airtight. While I suspect they will seal well enough for finishes that will dry hard when exposed to air, you can get a nearly perfect seal by putting a drop of thin CA glue into the cap and letting it wick into all of the tiny gaps between extrusion lines and layers.
2026-03-03
Add larger cap for new "Steward" bags that have two openings
Make top slightly thinner (2.4mm vs 3mm)
Start with the “0.15 structural” preset
3 perimeters
12 bottom layers (this will effectively give top of the cap 100% infill)
stagger inner seams
top infill pattern: concentric
Optional:
import the fuzzy skin enforcer
change the type to “modifier”
enable fuzzy skin on the modifier part
As with most of my designs, you can find the source CAD here at onshape.
If you need help filling your bags, check out my Funnel for StopLossBags.
License:
Creative Commons — Attribution — Noncommercial — Share Alike
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ex-nerd
