Just a quick hobby + learning project. If people are interested I am happy to post more pics. PLA exterior + TPU seals + Nylon (COPA) bushings.
Everything is 3d printed except the hardware & motor. The hose adapters have 1/4 NPT ends on them. NPT has a tapered thread so I found that I could screw them in partway by hand then heat them up slightly with a soldering iron to soften the PLA then screw them in the rest of the way. Makes a nice watertight seal despite the roughness of the 3d printed threads. If they start leaking I can unscrew them (leaving behind threads perfectly molded to the fittings) then add some pip seal tape and put them back in.
What do you guys think?
EDIT: here's a photo of the parts separate 
and a video: https://imgur.com/a/cd8co68
Are you printing gaskets in tpu or just laying filament and compressing that?
I usually go to a trick I picked up someplace off the Internet using silicone caulk squeezed into an appropriate diameter of fish tank airline tubing. (Or for much larger seals, flexible pc liquid cooling tubes.)
The trick is using an air compressor to blow it out of the tubing. (You can also make hollow seals by blowing the tube before the silicone is set.) then, just glue the ends with a dab of leftover caulk.