I've been trying to find a 3D printer filament which would not release any chemicals if in contact with heated water for a substantial amount of time. So far, I've easily ruled out both PLA and ABS, as they're not considered food safe from what I can find. I have found PETG filament, which seems to be food safe.

My question is: "Is there's anything special you'd have to do to make sure the print is food safe, or as in my case, to make sure it's safe for usage in a mug?".

I will be using a steel extruder as brass ones may contain lead.

  • $\begingroup$ Welcome to 3dPrinting.SE! I'm not quite sure your question is on topic for the site, but have a look at this article. I think it answers your questions. They actually suggest using PLA, because it is non-toxic. You have to seal it, though, as using it straight from the print bed is going to leave you seeping "stuff" all over the place (prints are very commonly porous). Anyway, there are others who are far more adept at this than I am who can give you a real answer. $\endgroup$ Feb 9 '19 at 14:50
  • $\begingroup$ @Pᴀᴜʟsᴛᴇʀ2 although that article also says that PETG is a good filament $\endgroup$
    – Melvin
    Feb 9 '19 at 14:56
  • $\begingroup$ All I was suggesting is that don't discard PLA as an option, mainly because it is non-toxic due to it being made from corn starch. $\endgroup$ Feb 9 '19 at 15:13
  • $\begingroup$ @Pᴀᴜʟsᴛᴇʀ2 Ok thanks :) $\endgroup$
    – Melvin
    Feb 9 '19 at 15:14
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    $\begingroup$ it's the tiny gaps that breed pathogens that causes 3d prints not to be food-safe, not the chemicals in the filament (although that could also be a concern). $\endgroup$
    – dandavis
    Feb 11 '19 at 22:52

Many manufactures list their filaments as being food safe, but I would not treat this as "gospel truth". Apparently, the FDA considers PETG to be safe for food contact, but they are probably thinking about injection-moulded and vacuum-formed parts. Unfortunately, an initial search of the FDA's website did not yield any definitive information.

Even if a particular filament is genuinely food safe, that does not mean that a 3D-printed part made from it will be food safe, since there will be an abundance of nooks and crannies where bacteria can lodge and reproduce. You would have to sterilise a utensil before and after every use to be absolutely safe.

Anyway, good luck with making a water-tight mug with an FDM printer. You will probably have to seal it to make it water-tight, and then it will be the food-safety of the sealant that you will need to worry about. I would give it a miss, if I were you (at least, for other people's use). Items intended for one-time use would be OK, I suppose.

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    $\begingroup$ Yeah, thanks, just realized I could just buy a normal mug and take it apart, as that will make my life a lot easier :) $\endgroup$
    – Melvin
    Feb 9 '19 at 16:48
  • $\begingroup$ This print is watertight: youtube.com/watch?v=OzfXVH59LjM $\endgroup$
    – FarO
    Feb 14 '19 at 19:07

As far as PET-based filaments go, most of them are FDA approved. So yes, "food safe". It's the process of 3D printing that ruins that. all the little layers trap just about everything and are hard to clean. If you wanted to boil your part, that might work, but you'd be better off buying a food-safe coating spray for your parts.

  • $\begingroup$ Much of the information is simply false. PETG filament exists but PET is not printable in itself. Also, while PETG in itself is a food rated material, this does not make either the filament or the printed object food rated as the manufacturing procedures have to be food rated also. $\endgroup$
    – Trish
    Mar 5 '19 at 1:22
  • $\begingroup$ LMK if you find a food-safe spray to seal your parts. I searched around the other day for such a spray but was dismayed to find nothing $\endgroup$
    – steve
    Jul 8 '19 at 22:10

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