Laminar Flow Garden Hose Head (mk2)

Read: How I Designed a 3D-Printed Laminar Flow Nozzle (2026-08-21)

Versions

mk1 - 2020-08-31
mk2 - 2025-06-04
mk3 - 2025-06-06

Intro

Like so many late-night YouTube voyagers, I was hypnotized by those crystal-clear “glass rods” of water pouring out of laminar-flow nozzles. Thanks to 3D printing—and the ability to swap files with strangers on the other side of the planet—I wondered: Could we skip the hardware-store scavenger hunt and make a nozzle you can download and print in one shot?

My first crack at it, inspired by Jarom’s “Ultimate Laminar Flow Nozzle” on The King of Random and later spotlighted on Prusa Live #26 (Matt’s “PrusaPrinters Picks”), almost nailed it. It did produce laminar flow—but only at gentle rates, and it still needed a pile of screws, gaskets, and off-the-shelf plumbing bits that loved to leak.

So here’s the reboot. This version is a true print-in-place design: drop the file into your slicer, press Print, and go make coffee. No combing the garage for the right thread, no spelunking for lost nuts, and definitely no 200-piece straw bundle. Just one print, one purge, and a flawless glass-rod jet.

Key improvements from mk1 –

• Square (now Pentagonal in mk2.2) body

  • Larger internal volume – than a same-footprint cylinder

  • Sideways printing – means no tall Z-height and the water flows with the layer lines, reducing turbulence

• Hexagonal tubes in Straightener Stage

  • A “squeezed” hexagon lattice replaces the original cylindrical array:

    • Self-supports at 45 °—no steep overhangs

    • Provides the > 40 L/D straightening ratio needed for crystal-clear flow

• Interchangeable Outlet lenses

  • Modular “lens” system lets you experiment with different jet diameters, materials, and finishes

  • 6 mm, 7 mm, and 8 mm inserts included

Version mk2.2 “fat”

Release 2025-06-14

• Keeps smaller form factor than mk3 but increased print time from mk2.0 / mk2.1

• No screws!

• Hexagon body to reduce overhangs and assist towards a single print design

• Increased width, reduced length - ie. “fat”

  • Supports uniform pressure

• Initial testing shows a much superior laminar results vs 2.0 / 2.1 and would highly recommend choosing this version for your prints

Version mk2.1

Release 2025-06-13

Brings some mk3 improvements back to mk2

• Removes taper towards the exit

• No supports needed

• Diffuser Stage built-in to print as well (introduced in v2-beta)

• Re-introduces interchangable lenses

Version mk2.0

Materials

Printing notes

• Designed for a 0.4mm print nozzle

  • when slicing, ensure hex pattern walls are 1 extrusion width

• Use a high-infill % as there is not much internal voids, but where there is – it lends strength to things like the hose attachments

• Increase bridging speeds over the defaults or the print will take a very long time

  • Lots of bridging is used in the initial Settling Stage and it is not important if there are artifacts

• Increasing water seal where the lenses attach

  • With no lens mounted – rub a little silicone sealant around the lens holder area and on the back of the lenses 

    • Let cure for the amount designated on the instructions