Knowing that most soda bottles are made from PET plastic, you’ve probably thought about how to make filament from it and have an endless supply of cheap printing material. [Mr3DPrint] says he has a method and shares a couple of videos that make it look easy. We wonder if the quality of the filament is on par with commercial products, but assuming the videos are accurate, it appears that the resulting filament does the job.
The details are a little sketchy, but it looks simple enough. The first step is to remove all of the indentations from the bottle. He has several demonstrations of it, some with compressed air in the bottle and others without. In either case, a drill holds the bottle through the cap and rotates it over a flame until the surface is smooth.
After being mostly smoothed, he cuts off the bottom of the bottle and, with a mounted razor blade, cuts the bottle into a thin strip. The next fixture is a standard hot end with a horizontally mounted 1.75mm nozzle. We’re assuming he drilled a standard nozzle with a 1.75mm hole or maybe a slightly smaller hole, taking the swell into account.
Presumably the razor produced strips narrow enough to fit onto the tip of the nozzle. He slides the plastic through and ties it to a string with a printer’s hot air brake, and a small machine pulls the rest through while it winds it onto a take-up spool.
We suspect that the diameter of the filament is distributed all over the place and we were wondering whether placing the filament vertically or horizontally gives the best results. However, this seems like an easy thing to do if you want to give it a try. In the comments, [Mr3DPrint] mentions some temperature ranges to get you started, but we haven’t found a reference for the constructions of the machines. On the other hand, they seemed easy enough to build, especially if you have a 3D printer.
The extruders we’ve seen are a lot more complicated. Most of them, however, use pellets.