Is 3D printed PLA waterproof?
3D printed PLA is not inherently waterproof, but it can be made more water resistant by post-processing. PLA, or polylactic acid, is one of the most common filaments for 3D printing and is bio-based and biodegradable. However, the material absorbs some moisture over time and has a certain porosity that allows water to penetrate if exposed to prolonged contact with liquids.
Key factors for waterproofing in PLA printing
Print structure and settings
The quality of the print plays a crucial role in its waterproofing:
- Stock binding: If the layers do not fuse properly, small microscopic cracks can appear where water can penetrate.
- Backfill: High infill models (100 %) are denser and have fewer voids where water can collect.
- Wall thickness: Thicker walls provide better resistance to leakage, especially if multiple perimeter layers are used.
Material properties
PLA is hydrophobic, which means it does not attract water as easily as some other materials. However, prolonged exposure to moisture or liquids can affect the durability of the material, especially as PLA is more susceptible to degradation at higher temperatures and in humid environments.
Finishing for waterproofing
To improve the watertightness, PLA objects can be post-treated by various methods:
- Application of epoxy resin: A layer of epoxy, such as XTC-3D, can create a smooth, impermeable surface that prevents water from penetrating.
- Heat treatment (annealing): By heat treating PLA, its structure can be strengthened, but this should be done with caution as it can cause deformation.
- Sealing with varnish: Waterproof varnish or spray varnish can also be used to create a protective surface layer.
The impact of design
A well-designed model with round corners and without small cavities reduces the risk of water leakage. Avoid including geometric details that are difficult to seal, such as deep cracks or thin voids.
Is PLA suitable for water contact?
PLA can work for short-term contact with water, for example in decorative items or storage that are not exposed to constant moisture. However, it is less suitable for long-term use in water or high-pressure applications, where materials such as PETG or ABS are better options. These materials have higher resistance to both water and temperature changes.
Conclusion
3D printed PLA is not naturally waterproof but can be modified to become water resistant with the right design, settings and finishing. If long-term waterproofing is required, it may be worth considering other filaments with better performance for these conditions, or using finishing methods to protect the PLA print.