A Simple Software Change to Add "Bricklayer" Mode to Slicers Delivers Truly Water-Tight 3D Prints

Mononymous maker and materials scientist Ben, of YouTube channel Designed to Make, has proven the efficacy of the "bricklayer" slicing method in creating water-tight 3D prints — testing them to depths only previously achievable using epoxy coatings.

"For the past year, my work has focused on designing and optimizing complex, submersible 3D prints — think print-in-place sea scooters and water pumps," Ben explains. "One of the biggest bottlenecks? Achieving reliable, pressure-proof waterproofing without relying on messy, time-consuming post-processing like epoxy or chemical smoothing. This project documents the results of my fairly rigorous testing of Bricklayer Printing (also known as Staggered Perimeters), a new technique that manipulates the internal structure of perimeter walls."

In traditional fused filament fabrication (FFF/FDM), a 3D print is built up from thin layers — with the print head lifting to deposit the next layer on top of the one beneath it. It allows for the creation of truly 3D objects in a single print run, but creates a weakness where the layers join — something that isn't usually a problem beyond the aesthetic visibility of "layer lines," until you get into trying to make objects water-tight.

When submerged in water, the tiny gaps between the layers create leakage points — and the deeper the water, the higher the pressure and the more water is taken on by the object. To address this, Ben has previously turned to post-processing: coating the 3D-printed object in epoxy to create an unbroken, water-tight barrier. "Bricklaying," though, promises similar results with zero post-processing — by staggering the outer layers like bricks in a wall, so that gaps do not reach all the way through the surface.

"The results are far better than I had hoped," Ben explain following testing: using only a software change to enable "bricklayer" mode in the slicer and an off-the-shelf 3D printer, Ben was able to create 3D prints that withstood up to four bar (60psi) of pressure — equivalent to a water depth of 40m or around 131 feet.

The full test is available in the video embedded above and on Ben's YouTube channel, with more information available on Hackaday.io. The modified version of Orca Slicer used in the test, which enables "bricklayer" mode among other changes, is available on GitHub under the GNU Affero General Public License 3.