Dishwasher safe materials

Not sure if this is the correct place, but I was looking at getting a reprap happening at some stage, and was thinking of making some cups. I presume that once set, the PLA and ABS would not be toxic? Are either/both dishwasher safe? Or would the dishwasher heat them up enough to warp them?

Some Chinese manufactures will blend (hide) toxic fillers within the plastic to dispose of it.
Lead, barium, cadmium, nuclear waste, etc. can easily be blended in during extrusion.

The only way to know if the plastic you are using is food grade is to request a material specification certificate,
and or send the plastic to a lab for analysis.

There are good labs in the US that test plastic, I've used them before.
The cost of the analysis is dependent on what chemical you want to identify.

I would not trust any material that originated outside of the USA or the EU, as they can still lie about it.

The simple answer is that PLA objects are not dishwasher safe because they would melt, and ABS is not food grade. Both types of plastic shed particles, but the PLA is water soluable, so it would eventually pass out of the body. ABS would probably get stuck in the liver.

Dang, so basically a reprap is not going to be able to print anything I can drink out of or eat off?

I notice you said the PLA is water soluble, I was going to also use it to make a waterproof electronic box (to house some electronics in the backyard from the weather), so would the rain destroy the housing?

I was also wondering if there is a PLA and/or ABS glue that would bond it like it was printed? I was thinking that with some projects (with overhangs too large, pivot points etc), is it possible to cut the mesh in half in the cad program, then print the 2 bits and glue them back together after and make it look like a single printed object?

3D printed objects can have small gaps in them which can harbor bacteria. Thus they are only for one off food/beverage use even if the material isn't toxic.

What about an option of something you could spray or brush over the top to seal the item and fill in the gaps?

There are many views and speculations about food contact and 3D printed items. Unless someone does a thorough study on each maker and each printer then we will never know for sure.

Personally I would eat dry food (cookies, MM's crackers...) off of ABS or PLA. I would drink from a PLA cup Taulman3D.com also has a new material that is certified food safe but even then if you had another type of filament in your machine first there may be cross contamination.

The fact is there are harmful chemicals everywhere and it's just a matter of avoiding them the best you can, even most water bottles are a known source of benzene and terrible chemical but we drink from them daily.

So my advise is if you want a cup, use PLA and use only for cold liquids then hand wash. You want to make a bowl for crackers or jelly beans, MM's that kind of thing then either PLA or ABS.

The only "coatings" that are guaranteed food safe are glass and ceramic and neither can be applied to plastic. Anything else would be a polymer and have the same general health concerns as ABS.

No worries, thanks for that. So what are plastic cups made of? Is there a material for repraps the same? They can go through the dishwasher as well.

There are many types of plastics used in cups. PLA is used to make those disposable clear party cups. There are also AS plastic cups (those unbreakable plastic ones used in restaurants). I think even some acrylic ones.

The problem is, even if it's a known plastic type, you need control over the process to assure nothing nasty gets mixed in with it and passed off as good. Also as mentioned the tiny crevasses from 3D printing are good places for bacteria to breed and become dangerous. Most molded cups have a very smooth glass like inner surface to prevent build up and make cleaning easy.

If you have a plastic cup at home and wash it inside with an abrasive pad made for scrubbing pots and pans you can have the same problem.

Ok, so if we could work out what material is used in those cups (im referring to the slightly flexible ones, not disposable), and made a reprap that only printed that material, they should be non-toxic and dishwasher safe. As far as the gaps go, is there something that could have a hot enough surface (maybe a soldering iron) that could melt the inside wall of the cup to make it dead flat?

Just bought a Printrbot and still waiting for delivery so Im just speculating here....

They use paper cups dipped in nasty petruleum-basic peraffin so maybe PLA cups dipped in bees wax!?!
Just a thought

There are also different bioplastic varieties and some are not biodegradable, but Im not sure if they would be printable

Although they would maybe be "semi-disposable" ?

Edited 1 time(s). Last edit at 07/02/2014 01:29AM by colvillewildcrafting.

Best option for making food-safe products would be to mount a milling head, cut a wax original, use that to make a mold out of silicon or some other suitable material, then mold as many copies as you might wish.

Taulman has a product called t-glass that is certified for direct food contact [taulman3d.com]

Not sure if it would be dishwasher safe but might be worth a try.

If you ran other materials through the hotend before I might extrude a few feet or more of it before making something for food to clean out any contaminated in the hotend.

is there also some concern over the materials I the hotend itself?

existing manufacturing techniques for plates and cups are more than sufficient, I understand that it would be cool to 3D print your own stuff, but not yet safe to do so.
you could always try working with 3D printed ceramics, you would still have concerns over Bacteria growing in the lines between layers.
two ways to overcome that would be to print slightly thicker outer walls and sand smooth before glazing, or scrub and soak in a sterilizing solution similar to those used in restaurants.

I wonder about using a paste extruder to make objects out of Bakelite or other similar thermosetting plastics, which allow quite a bit of working time before they cure.

In any case, there's certainly nothing stopping you from getting such an extruder and printing with porcelain clay. Then it's just a matter of glazing and firing it and you've got the most traditionally food safe material you can find... (well, aside from paste extruders being a bit of a new thing, I suppose.)

Bakelite is compression molded.