Filament extrusion is a difficult thing.
You need to keep in mind all sorts of things just to be able to get a consistent width.
Things like:
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Plastic material type (some can only be recycled so many times)
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A single spec of dust can clog your nozzle
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combined multiple materials will give inconsistencies
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if the plastic isn't ultra mega dry, the water will form bubbles because of steam
Creating homemade filament is not for the ones that get frustrated easily, they are far away from the quality and user friendliness that modern 3D printers have. But it is a nice little project to keep you busy.