On the issue of food safe printing,

On the issue of food safe printing, I’ve read that no printed model is truly food grade due to small cracks and pours from bubbles within the final printed item being hotbeds for bacterial. Seeing stuff like this concerns me: http://makerbot.tv/nfh/makerbot-tv-season1-episode9-2/

Yet, I’m looking food grade PLA sources to make molds to be cast in more kitchen-ok material. Anyone got good sources or experience?

I’m also looking to purchase a Prusa all steel extruder to make it even more food safe. They are out of stock on Ultimachine :-/

I’ve heard there are food-safe shellacs you could use over a PLA mold, but information on this is usually pretty dubious. Either way, you end up with something that isn’t dishwasher safe, which makes it pretty impractical.

Theoretically, ABS and PLA can both be food safe, but in practice the structure becomes uncleanable, so even if no heavy metal contamination or impurities exist in the printed plastic, it still can’t be considered food safe. I’d be interested to see whether vapor smoothing can address the structural issues.

ABS is high-temperature enough for a low-temperature pasteurization process to sanitize it. Not the most practical, but more so than irradiating it (which should also work).

Acetone smoothing should get rid of a lot of the homes for bacteria, but if you use too much heat it can boil the acetone out of the plastic and cause pitting that would create new ones.

On the plus-side, it’s easier to get water-tight surfaces with a reprap-style printer than with the commercial models.

BTW, here are some links for those sugar printers I was telling you about the other day:


http://www.candyfab.org/
http://blog.reprap.org/2012/07/on-challenge-of-3d-printing-sugar-for.html