No, you can't 3D print gunpowder, as far as we know, but you can actually make fireworks. Christophe Hermanns of Belgian-based Vigo Universal used 3D printing to create several devices used to hold live fireworks in Les Orryflammes' pyrotechnic shows.
The artistic troupe employs handheld fireworks apparatus to produce a highly animated stage show, as you'll see in the video.
We spoke with Hermanns, who told us:
We use a 3d printer from Makerbot and we print items in PLA and ABS plastics. We have multiple 3d printers in our office. The item's design was realized by our graphic designer. Before using it in fire show our engineer make some simulation to be sure they are safe and they don’t melt. The plastic part is re-usable, we just need to change the fireworks part.
Some may say you can't make production-ready parts with 3D printers as inexpensive as a MakerBot, but Vigo Universal disproves that notion. Would you have the confidence to hold lit fireworks with your 3D print?