*WORK IN PROGRESS

I'm playing around with using white PEX plumbing pipe as a diffuser for LED strips. It's pretty cheap and available at most major hardware stores in North America. It can also be cut to any length with a hacksaw or tubing cutters. It's probably not ideal because it holds in heat a little too well and commercial products diffuse the light better, but I'm playing around with it anyway. 

I wanted a pipe to stand vertically in a corner but couldn't find any clips that wouldn't show the screw so that was my first design. I also wanted to use aluminum flat bar to mount the strips inside so I could aim them and have two strips facing opposite directions.

In this version, I used white lights on the outward facing side and red lights on the inward facing side. It gives it a cool cartoon laser kind of look that's hard to capture on my phone. Unfortunately, the LED strip I used started turning yellow in some spots for some reason. I think it was just a cheap ebay reel so maybe they are just junk. I have another one behind my couch that uses a much brighter commercial-grade strip and it works fine so I don't think it's the heat.

Anyway, I added one regular end cap, one “base” endcap with a slot to let wires through, and a “top” endcap that has a tab with two holes for zip-ties. I drilled two corresponding holes in the aluminum flat bar so the cap holds the weight from the top. This also allows you to rotate the cap to change the direction of all the LEDs.

You could, of course, use these for any type of LED strip. It just needs to be 1/2" (13mm) or narrower.

All files are +/-3% depending on how tight you want the fits to be. They print pretty fast so you can experiment. If one is just a tiny bit too tight you can hit it (the caps) with a heat gun or hair dryer for a little bit but it might be tricky to get back off.

I used PLA with all your basic settings, 15% infill.