Glow-in-the-dark projects aren’t that uncommon. You can even get glow-in-the-dark PLA filament. However, those common glowing items require a charge from light, and the glow fades very quickly. [Ogrinz Labs] wasn’t satisfied with that. His “Night Blossom” 3D-printed flower glows using radioactive tritium and will continue to glow for decades.

Tritium vials are available and often show up in watches for nighttime visibility. The glow doesn’t actually come directly from the radioactive tritium (an isotope of hydrogen). Instead, the radioactive particles excite phosphor, which glows in the visible spectrum.

Once you have the vials, it is easy to understand how to finish off the project. The flower contains some long tubes inside each petal. There are also a few tiny vials in the center. The whole assembly goes together with glue.

Tritium tubes are widely available. There are, however, fake tubes, so if you get a good deal, you might want to make sure you are really getting a tritium tube. One way to tell is that fake tubes will glow brighter when you briefly expose them to a bright light. A real tritium tube won’t care if you hit it with light or not. Fake tubes are often cheap, and real tubes are not. Also, because tritium is radioactive, there may be laws or regulations about buying, selling, and possessing them, depending on where you live. The truth is, these little tubes have tiny amounts of material, but if you break one, you probably shouldn’t sniff the contents.

There were at least two versions. The first was FDM printed in clear plastic. Resin and pigment added color, and a clearcoat sealed it all in. The second version uses resin printing along with pigments. The FDM part diffused the light a bit, which might benefit this application.

If you don’t need much power, you can use these vials to make a simple nuclear battery. Afraid of radioactivity? Well, that’s generally a good idea, but in this case, you are probably fine.