What is the best plastic for use in an Aquarium? Can't float, or release toxic materials

Hi everyone. I am looking for advice on which plastic is best for use in a fish tank.

I need it not to float, but in a worst case scenario, I can design a small metal piece to be embedded in the plastic to force it to sink.

Most importantly, I need the plastic not to ever leach chemicals into the water, regardless of the pH. Does anyone have a suggested plastic for this? If the only plastic that would not be poisonous also floats, that's no problem to work around.

Thanks!

Because of the printing process, I think all would be harmful if used in an aquarium. There can be material that can come free, and it may not be "toxic" but much like us, breathing in Nylon dust, or any other material is not healthy. You could try to seal the prints in a clear water proof material though.

So it is the printing process that makes you weary of its safety? Rather than the actual ingredients of the plastic?

You could also check the MSDS (Material Data Safety Sheets) for each material which might give you some information. Personally I would not use any of this stuff for aquariums or terrariums with real fish or other critters, unless of course you could safely seal or glaze the items.

Perhaps you could also print items to make molds and then cast non-toxic food safe materials to create your items. Or perhaps you could put the items in a tall glass container in your aquarium that isolates the printed parts from the water in the rest of the aquarium.

I appreciate the responses so far guys!

I guess what confuses me is that there are so many different plastics out there and many are used in aquariums. I will try to see which ones are.

So Shapeways does not make anything with Polyvinyl Chloride?

Also, I am not seeing any MSDS documents anywhere.

WSF, Detail, FUD.

All are on the individual materials details page at the bottom of the properties section

I wouldn't assume that things you buy in stores are completely safe for aquariums either. Odds are that just about any material, with the possible exception of glass, might leach larger amounts of materials such as chemicals or metals into water creating toxins or changing water pH. And if the items are manufactured and sold by less than reputable sources the fish may kick the bucket sooner rather than later. You could use a test tank with "guinea" pig fish to see if they last more than a few weeks before using a material in your good tank. This might be a good idea for any thing used even if bought in a pet store, although it might be unfair to the poor test fish. Soaking your item in water for several weeks and replacing the water every couple of days might also help to leach out the majority of any nasties before you use it with fish.

Some other suggestions might include dipping or soaking your material in thin CA (super) glue to seal it up. Or possibly even better than that would be to use a clear aquarium quality 100% silicone glue. If aquariums are built with the stuff it must be safe! You should be able to brush it on the piece but it would need 100% coverage. The drawback is that if the coating seal ever breaks it could allow a path for contamination to croak your fish.

I managed to finally find some articles on it. It seems to be a common debate, but most seem to agree that the majority of plastics are okay for fish tanks, but it is the additives in the plastics that may be toxic. So, aromatics and other things besides the polymers.

Is Shapeways plastic pure?

I would try to test all of this out in one of my tanks. A good indicator seems to be the texture of the plastic when drying it off after being wet for while - as in, does it become brittle, or soft.

There will be a good few tests I do, but it appears that most of the plastics are aquarium safe, and that the lack of confidence in that is based on scientific studies purporting one result or another.

But there are tons of plastic products used in fish tanks. And I have never heard of anything definitive about them being dangerous. I will definitely research that more and choose my material appropriately.

Another note.

It looks as if the polyamide default white plastic is perfect. Polyamide is nylon or a derivative, which is no more or less toxic in a fish tank that PVC, and other commonly-used plastics (from what I have found so far).

But the detailed white plastic is pretty darn toxic, and definitely not for use in something like this.

Need to be in touch re your findings. Have similar need. Don't understand your last comment re white plastic being toxic.

Happy to share concepts with you. Serious entrepreneur. Please reach out. Does the polyamide plastic sink? who fabricates.

John

Seethis recent thread, there are aquarium-safe coatings available for post-processing the printed parts. AquaNovae's problem with the "white detail" material (note NOT the "strong&white") is probably that it is an acrylic polymer: While the cured, perspex/plexiglas/PMMA-like material is not toxic, the raw material is classified as a skin irritant for humans and might be harmful to at least some aquatic species (though the MSDS does not list it as a known environmental hazard). Some of it may stay adsorbed or trapped in the product.