Hello! I’d like to print food safe objects to use in the kitchen, like spoons and glasses and so on. Looking on the web it seems that the problem with 3d printed objects is that the space between layers is like bacteria’s heaven, so after one use you have to throw them away. The only way I found on the web is “coat with resin”, but I don’t like this very much, as scratches can remove the coating. also “print a negative and use it like a stamp” seems like too much work for a simple spoon.
so the question is, what if I use a filament that can go into the dishwasher, so I can clean it with boiling water? the web didn’t help me much on this, as I found different opinions on the matter: some people said that PETG could go in the dishwasher, some said no.
what is the real answer? can I 3d print PETG objects, use them, put them in the dishwasher, and then safely reuse them?
The glass transition temperature (the temperature where plastic starts to become malleable) of PETG is 85°C, so if you put a PETG spoon in boiling water, it would deform and become pretty useless. However, if you used a high temperature plastic with a glass transition point above 100°C, you might be able to get away with this method.
Also, just to clarify, a dishwasher does not get to 100°C. You could use it to get the initial food off, but you would then need to boil the utensils manually on a stove to actually sterilize them.
You can sanitize at boiling, and far below that too. For actual sterilization, you’d need to be above boiling using something like an autoclave or pressure cooker.