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PP3DP ABS safe for dry food?

Posted: Fri Nov 30, 2012 7:12 pm
by CohesivePD
I'm a little unclear when it comes to "food safe" plastics and what exactly that means from bio-chemistry standpoint. It is my understanding that the concern with food safe vs. not food safe often lies in the possibility of seepage of certain chemicals (BPA comes to mind, though that isn't used in ABS as far as I know) into liquid or semi-solid food, but does this still apply to spices and other dry forms of food? The reason I ask is because I want to 3D print a salt and pepper shaker, but I'm not completely sure whether or not that would be fully safe. Does anyone know more about where the line is drawn between safe and not safe food uses for 3D printer ABS? If the plastic isn't intrinsically safe, does anyone know of a good, thin coating I could apply to make it so?

Thanks.

Re: PP3DP ABS safe for dry food?

Posted: Mon Dec 03, 2012 2:30 pm
by roller
The chemicals can come out from the plastic even with dry materials through off-gassing by the plastic and surface reaction which salts could well generate.

The problem is that:
- there is more than one grade of ABS which can slightly different properties and although most are mostly benign maybe the one we have isn't
- although the filaments are labelled ABS I suspect many are not purely ABS. I think Stratasys ABS for example contains a proportion of polycarbonate
- the ABS contains pigments to give it colour - these pigments could be made of all sorts of stuff and if the manufacturer isn't making it for food grade they may use something a little incompatible ie poisonous with food
- Even if you ABS is food safe before printing, it may not be after. By heating these plastics we may destabilise it's constituents and form a chemical that is nasty ...

so all that says I wouldn't risk it even with PLA which is much more benign because, of course, the mysterious pigments in them. Though I have used clear PLA for cookie cutters figuring it was a brief encounter and therefore low risk.

So I think you need to look at a coating. Food grade silicon coatings are a common solution but you really need to look at how and where you will make contact with your contents. Keep off gassing in mind - any vapour the plastic releases will be trapped inside the container so you really need to be sure you seal off those inner surfaces in an air tight way to be sure...

or print some and get them tested... and retested every time you change spools. Sometimes unis will help (here in Australia at least) as an exercise for students.

Re: PP3DP ABS safe for dry food?

Posted: Mon Dec 03, 2012 8:22 pm
by ftdesigns
also, don't forget about microscopic shards of plastic, which is something you need to consider even when ripping open any plastic bag containing food (should use scissors).
my prints are full of tiny 'hairs' and pieces.

Re: PP3DP ABS safe for dry food?

Posted: Tue Dec 04, 2012 2:01 pm
by juancr
I asked to pp3dp people some months ago:
"I would need general and mechanical characteristics of your ABS filament and if it is safe for food uses (glasses, knife, dish, etc.)"

The answer:
" As the ABS has no certification of the food security, please do not print the models for food use."