You can do some pretty amazing things with Lego’s Mindstorms EV3. For example, you can use it to turn an ordinary hot glue gun into your very own 3D printer. Yes, for real.

As you can imagine, the resulting printer isn’t capable of producing the kind of high-quality pieces that Makerbot or Solidoodle owners can. The biggest shortcoming is the printer’s “extruder,” the hot glue gun. It’s just not very easy to make them dispense a nice, consistent strand of glue (something you’re all too familiar with if you’ve ever used a hot glue gun). The printer is also quite slow, since it pauses for 30 seconds to give each layer of glue enough time to cool and cure.

That doesn’t make the printer that Instructables user William created any less impressive, though. It’s amazing to see in action, even if the squares it lays down tend to have very heavy corners and thin, shaky connecting lines. This is just a plain old glue gun, just like the one (or three) you have stashed in your cupboard. It’s not like the manufacturer ever intended it to be used the way William’s using it.

Not everyone has a $350 Mindstorms EV3 kit laying around, however. If you’re starting from scratch, that might be a deal-breaker for you since it’s already getting into low-cost 3D printer territory. There are plenty of other things you can build with Mindstorms, of course, and it’s not as though anyone would rush out and buy one just to make a 3D printer.