I think it would be hard to find someone who didn't know what a Nalgene water bottle looked like. These ubiquitous vessels are a common sight everywhere I've been. There's one sitting two feet from me right now, in my lunch cooler.
We decided to test extrusion with Nalgene bottles because of their common use, and the plastic's properties. If you've ever owned one you know how durable they are. Scratch that, these things are nearly indestructible. More on that later.
The plastic used in these containers is called Tritan. If you remember a few years ago, people were concerned about the health impact of BPA plastic. At the time, most water bottles were made with BPA and it was Tritan that came in as a replacement.
Extrusion was standard from a preparation standpoint - remove the stickers, remove the caps. If these weren't new bottles, we'd have cleaned them very well. The caps were made of something other than Tritan, probably HDPE, so we put them aside.
Grinding was the biggest challenge, because of the durability of the plastic. We considered breaking them up before grinding, but that was challenging. In the end, it would have also been unnecessary.
We ran the bottles through two different grinders in order to get filament the proper size. The first grinder did a good job of reducing the intact bottles but didn't quite produce filament small enough for extrusion.
We've worked with Tritan plastic in the past and had success, so we expected we'd make this work, too. If you want to see the full settings for extrusion, you can check out the report, linked at the end of this page.
One of the coolest parts of the process was that the color of the plastic stayed intact, through grinding, extrusion, and printing. While the visual element of spooled plastic is far from a reason to do anything, this stuff looks great on a spool.
We made a few test prints, starting with our standard Filabot test. From there we went on to print a wide-mouth drinking adapter for a wide-mouth Nalgene bottle. It not only worked, it worked very well.
While you're unlikely to find yourself with the need to make filament out of a few-dozen Nalgene bottles, doesn't it feel good to know you good?
To see the video-recap of this extrusion test, check us out on our YouTube channel. And to get access to the full write-up, including specs and more, click here.