I tried, although it was more of a diffuser window, which is what I wanted.
The way to make a light pipe is probably to cut the raw clear filament to the right size and print a hole for the resulting light pipe.
I now have some clear hot glue that I plan to try for a few optical applications.
Been printing for about 6-7 years. Started exclusively with PLA but found that it doesn't hold up well for certain applications. Now about 50-50 PLA vs PETG. For specialty items I use ABS and TPU when called for, but that's rare. Use a lot of Prusament brand filament - the quality does seem to make a difference.
Interesting idea! I might try a roll of PETG.
Mostly recycled ABS with some PETG and PLA.