Why does my 3D printed vase leak?
A vase printed in vase mode has a wall only one extrusion line thick. One thin or under-extruded stretch lets water out, and so does a weak joint where the wall meets the base. The usual fix is more plastic: 105 to 110 percent flow, an outer wall widened to 0.6 mm and 5 or more bottom layers.
Settings that make a vase hold water
| Setting | Value | Source |
|---|---|---|
| Outer wall width in vase mode, 0.4 mm nozzle | Raise from 0.45 to 0.6 mm | Prusa Knowledge Base |
| Flow (extrusion multiplier) | 105 to 110 percent | Prusa Research blog |
| Flow ratio in Bambu Studio | Up 0.02 to 0.05: from 0.98 to 1.00 through 1.03 for PLA Basic | Bambu Lab Wiki |
| Nozzle temperature | 5 to 10 °C hotter | Prusa Research blog |
| Layer height | 0.15 mm or lower | Prusa Research blog |
| Bottom solid layers | 5 or more | Prusa Research blog |
| Bottom surface pattern | Concentric | Bambu Lab Wiki |
The flow, temperature, layer and bottom-layer figures come from Prusa Research’s Watertight 3D printing PT1 tests on vases and cups. The 0.6 mm outer wall is the Prusa Knowledge Base’s vase-mode example. The flow-ratio step and concentric bottom come from Bambu Lab’s leak guide. Bambu warns that these settings cut the risk but cannot guarantee a leak-proof print.
Are 3D printed vases waterproof?
They can be, but not by default. Prusa Research found thin-walled vases printed with its regular 0.15 mm profile leaked a lot, while thick-walled ones mostly held. In the same tests, one wall in vase mode held water in every material tried. Prusa’s conclusion is that the right settings, plus a little post-processing, make nearly any print waterproof.
Bambu Lab’s leak-guide vase profile does not use vase mode. It prints PLA (polylactic acid) Basic with 2 wall loops and a 0.5 mm line width on a 0.4 mm nozzle, at 0.1 mm layers with no infill. With ink-dyed water inside, the tissue under the vase stayed dry for 48 hours. If a single spiral wall keeps failing, switch vase mode off and print normal walls. The per-material wall counts are on how many walls make a print watertight.
Why a one-line wall leaks
In vase mode (Spiral Vase in Bambu Studio) the slicer prints the wall as one continuous spiral: one perimeter, no infill, no top layers. Bambu Lab’s spiral-vase page notes there is no seam above the bottom layers. That removes the main leak path Prusa found: the seam where each layer starts and ends. It also removes any backup. A normal wall has several overlapped lines that would all have to fail in the same spot. A spiral wall has one. Prusa calls extra flow probably the only way to seal a vase-mode wall without post-processing.
The base is the second weak point. The bottom is solid layers with the single wall laid around them, and Prusa traced leaks to the transition between solid infill and perimeters. Prusa’s test bottoms held with 2 to 7 solid layers and 8 perimeters. Prusa suspects the first layer, squished into the bed, did most of the sealing. A vase with one wall has less margin, so Prusa’s advice of 5 or more bottom layers applies.
- One-line spiral wall
- Solid bottom layers
- Wall-to-base joint
Where it leaks tells you why
Fill the vase, stand it on a dry paper towel and see where the water shows up.
| Where the water shows | Likely cause | Fix |
|---|---|---|
| A vertical stripe down one side | The layer seam on a normal-wall print | Print in vase mode, or add walls and flow |
| A ring at the bottom edge | Weak bond between the bottom layers and the wall | Raise flow; raise infill/perimeter overlap to 25 to 35 percent (default 10); use a concentric bottom pattern |
| Through the middle of the base | Too few bottom layers or a poor first layer | 5 or more bottom layers |
| Beads all over the wall | Under-extrusion or a too-thin line | Raise flow and temperature, widen the outer wall, dry the filament |
| A few pinholes | Dirt or a partial clog in the nozzle, or moisture bubbles | Clean the nozzle, dry the filament |
| Dry at first, damp after weeks (PLA) | PLA swelling and wicking water | Coat the inside or use a liner |
The overlap figures are from the Prusa Knowledge Base; the nozzle cause is from the Prusa blog. Bambu Lab’s guide recommends pre-drying the filament to avoid holes in the extruded lines.
Is a PLA vase waterproof?
Yes, when printed right. Prusa found that PLA does not dissolve in water, but it can swell and act as a wick, so in theory a filled PLA vase could start leaking after several weeks. That never happened with Prusament PLA in Prusa’s own tests, including PLA flower pots watched over a long test period. A single vase-mode wall in PLA held water, while with normal walls PLA needed 4 perimeters. Bambu Lab’s leak guide includes vase profiles for PLA Basic and generic PLA.
How to seal or waterproof a 3D printed vase
If the settings fixes still leave a damp towel, seal it or line it:
- Acrylic lacquer spray. Prusa calls clear acrylic varnish the simplest method: spray the vase inside and outside a few times and let it dry. Spray types are compared on waterproof spray for 3D prints.
- Brush-on epoxy. Prusa warns it is messy, gives off fumes that call for gloves and a respirator, and can take several days to cure. Mixing, pot life and cure times are on sealing a print with epoxy.
- A liner. Drop a glass jar or a plastic cup inside, and the printed vase only has to look good. It needs no special settings or coating.
Before the vase goes on furniture, run the overnight leak test.
Sources
- Watertight 3D printing PT1: Vases, cups and other open models (Prusa Research blog) (accessed October 10, 2026)
- Layers and perimeters (Prusa Knowledge Base) (accessed October 10, 2026)
- Watertight prints (Prusa Knowledge Base) (accessed October 10, 2026)
- Guide to reduce the risk of prints leakage (Bambu Lab Wiki) (accessed October 10, 2026)
- Spiral Vase mode (Bambu Lab Wiki) (accessed October 10, 2026)