context: 3D-print material like PLA is food safe, but due to the many edges and lines between the print layers it is basically impossible to clean to a food safe degree.
While theoretically you can get certified food-safe blend of PLA, the rest of the extrusion path must also be food-safe... I personally am not fond of eating hot degraded PTFE... Or the trace remains of charred ASA/ABS I printed last week through the same nozzle... Or in fact any of the various coatings of the heated bed or leftover trace amounts of previous prints...
It's just a black hole that I choose not to get into by not printing stuff that's expected to be in contact with food.
> I personally am not fond of eating hot degraded PTFE
If this is a problem, you should buy a new printer that actually keeps the filament conduits away from the hotend. This is a health hazard regardless of food safety - decomposed PTFE is nasty stuff to breathe in.
> Or the trace remains of charred ASA/ABS I printed last week through the same nozzle...
Fair enough, but I would also say that you should be purging old filament anyways before starting a new one. My slicer does this by default.
> Or in fact any of the various coatings of the heated bed or leftover trace amounts of previous prints...
These days, heated beds are covered in PEI. That's food-safe too.
I think your take is a little panicky and not supported by the evidence. It is perfectly fine to print single-use food stuff out of PLA, especially if you just have a roll or two of the pure (undyed) stuff around. You're much more likely to get sick from the food itself than the plastic it touched for a little while, and PLA is relatively biodegradable compared to most other plastic foodware.
> If this is a problem, you should buy a new printer that actually keeps the filament conduits away from the hotend
The filament is still in contact with the PTFE tube, the PTFE tube is also hand-cut by me and in motion with the head so it undergoes wear. Even when you get an all-metal hotend there are ways of contamination by PTFE passing through the hot-end and degrading into harmful chemicals.
> purging old filament anyways before starting a new one. My slicer does this by default.
I do purge and cold-pull. While this removes the bulk of the old filament it does not remove all trace amounts of it.
> These days, heated beds are covered in PEI. That's food-safe too.
It is food-safe only if it was produced in a food-safe manner and was kept food safe afterwards, including no contact with pollutants.
Since you mention evidence, I have no way of proving that anything I produce is food-safe. Literally not anything in my extrusion path is certified food-safe, let alone I have equipment to test.
The fact of the matter is that glass, ceramic, and stainless steel has replaced any vessels that are in contact with food at home, and I don't intend to look back on that, and I am in fact looking to replace anything in regular contact with human skin with non-synthetic/non-plastic alternatives -- this includes clothes, bed sheets and others.
While there is the hacking mindset, people also need to be responsible, and my red lines on that is making stuff with a safety aspect to it. Food safety is safety as much as fire and electrical safety in my book.
Also lead from brass nozzles. I think the risks are overblown, but recommending anything that is not recognized as food-safe for use with food is a liability, better safe than sorry, as they say.
There are food safe coatings though, these deal with the problem by making your 3D print not in contact with food.
The main solution I've heard is to just encapsulate the whole thing in foodsafe epoxy. Then it doesn't matter as much what the inner material in so long as you monitor for damage.
Yeah there are a couple that claim to be like this [0] one, and there are FDA standards to follow for that claim. I wouldn't use one on a cutting board or anything that gets scraped or cut on and you need to let it cure waaaay longer than normal but yeah there are options out there.
