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I want to print a lemon squeezer and I would prefer to use PET-G. I don't know if it is safe to use, because lemons contain lots of citric acid. Does it dissolve PETG? I haven't found an answer anywhere on the Internet. There are generally few things that dissolve PETG. These are aromatic compounds like toluene, phenol etc.

I know my model will be food safe, as PETG is food safe, I'm using one without a dye and my nozzle is made out of steel, not brass. I think bacteria growth inside little gaps/between layers is impossible, because the citric acid is quite strong and will kill nearly all of the germs.

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According to kmac-plastics, PETG is stable at temperatures below 50°C specifically for citric acid (also acetic acid) and others on the linked list. It is also safe with diesel oil and many alcohols. The list is illuminating with respect to the variation of tested compounds.

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The PETG is food safe (plastic water bottles are made of them), however the colour additives may not be a) stable, or b) food safe. If you are going to make a lemon squeezer then I would suggest that you use a virgin material that is just pet-g with no additives.

However, you could only ever use it one. Any food particles that get stuck in between the fine layers of the printed part, will cause bacterial growth. If the walls are porous then the juice can get inside of the part and create a breathing ground.

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    $\begingroup$ Yes, I know that the dye might not be safe with food, the filament I'm using for this project doesn't have any dye/additive. But yes, that's a good point. As for the bacteria, I've heard that the citric acid in lemons makes it significantly harder for germs. I think that's true, because I once kept lemons cut in half in a fridge and they were still perfect after two weeks. $\endgroup$
    – StLuke5
    Commented Aug 24, 2019 at 15:14
  • $\begingroup$ Hmm... using citric acid to sterilize 3d printed objects. I wonder. $\endgroup$
    – user77232
    Commented Aug 25, 2019 at 3:29

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