A Reliable Method for 3D Printing Watertight Hulls

3D-printed bodies tend not to be reliably watertight, because tiny gaps between layers and walls can let water seep through. A well-tuned printer with good settings may be able to produce parts that are watertight near the surface, but even those can fail at greater depths. That’s why Ben came up with a more reliable method for 3D printing watertight hulls and actually put that method to the test.

This method relies on “brick layers,” which is an option in Nanashi’s fork of OrcaSlicer. Slicers typically extrude outer walls next to each other at the same height, then fill the inner space between outer walls with the selected infill pattern. The brick layers setting changes that, alternating height between walls. That results in a staggered pattern, with extruded walls “interlocking” in a tighter manner.

Ben hypothesized that brick layers would be more watertight. To test that, he built a test chamber capable of increasing water pressure up to four bar. That is equivalent to 40 meters of depth in water. He then printed test parts. Those are hollow on the inside and shaped to highlight potential failure geometry.

That testing showed that Ben’s hypothesis was correct. Brick layers do help to make the 3D-printed parts more watertight.

Ben found that the best brick layers settings, without using any kind of coating or reinforcement, were with ASA at 1.05 or 1.10 extrusion multiplier and a 3mm hull.

That is an easy configuration to setup. So if you need some watertight parts, this sure seems like the way to do it.