Am wondering if anyone has experimented with polymer clay pieces yet in their aquariums, since the last message was posted here.
I've just purchased my first indoor aquarium (have had an outdoor pond over 10 years) and am going to try some polymer clay pieces in it, I think.
I'd like to clarify some of the messages above with my own knowledge of polymer clay, which I have used daily for over 5 years now and have read extensively about the safety issues of it. I have not, however, ever heard of any other polymer clay artists, who have used an item made out of polymer clay in a fish aquarium, so I think this is completely uncharted territory.
First, per the comment above that it has some kind of oil in it to help with mold release, that is incorrect. The oily character of uncured clay is the plasticizer, which keeps the clay soft until curing. Yes, it is petroleum based, as all plastics are. After curing the clay at the proper temp and time, the plastizer become bound to the polymer molecules and no longer leaches out of the clay.
There have been warnings put out about not using finished polymer clay pieces with food. This is not because of anything toxic that leaches from the piece, but because the clay is slightly porous and can collect harmful foodborn bacteria over time. I would think that this would be a good feature in an aquarium setting, where the more surfaces you have for beneficial bateria to grow, the better the balance is. However, like I said, an aquarium environment is probably quite a bit different than a pond environment. I would appreciate all thoughts on this.
The OSHA warnings that are out there, that you can read on the Sculpey website, all apply only to the uncured clay and contact with the plasticizers in it. However, many polymer clay people have been exposing this to the skin on their hands for over 10 years, with no adverse effects. The cautions about not using a tool for food items ever again, after it has been used with polymer clay, make it sound like it leaves a very toxic residue that can't be removed. It is the consensus of the polymer clay community, that these warnings are put out there for the sake of erring on the side of caution, by the manufacturers. Most polymer clay users, including myself, are not totally strict about following these cautions, and I have never heard of any reporting any kind of an illness that thought might be connected with contact with polymer clay. I have been forgetful and have eaten hand snacks, at times, while I'm working and my hands are coated with the residue.
So, in my opinion, using decor made out of polymer clay, in a fish tank, wouldn't be any more harmful than using the plastic resin decor found in the stores, which is also coated with paints of unknown origin. Even so, I would not recommend anyone else jumping in and doing this. It is one of those theories that has to be borne out by testing, so that is what I am planning to do. I am going to start up my aquarium and create some polymer clay pieces to put in it, after it has been established for a month or so. I only plan to have a couple of fish in it during this time. After six months or so, I'll report back here. I use two different brands of polymer clay, and will be trying both of them at different times.
Please let me know if you have any other questions about polymer clay or suggestions of what to test for-