Are all plastics safe?

hey guys, just a quick question, still playing with ideas for my new tank and was wondering are all plastics safe to put in water with axies? or are some dangerous?

Not all plastics are created equal. Some are coated with slip agents, plasticized with toxic compounds that may leach out or otherwise adulteerd with pretty much anything including detergents. Some plastics that are commonly considered aquarium safe include rigid PVC, high density and low density polyethylene (HDPE and LDPE.)

Abrahm nailed the safe plastics list pretty well. I'll add to it with acrylic (clear), PETE 4, PTFE and polycarbonate. Urethane is also generally safe, but many types can degrade structurally over time in water.

To the do not use list, Nylon is number one, less for toxicity (though it does leach a few things out when exposed to water) but more for its tendency to absorb water and break down over time. Nitrile, neoprene, BunaN and similar rubberized plastics should also be avoided. Silicone plastics are safe only if specifically rated as such for aquarium use(This includes silicone sealants and RTV).

Polystyrene foam (both open and closed cell) is a touch and go situation. One must be very careful as to the source as many of these foams ( such as the ones used for industrial packaging and insulation) can be contaminated with everything from machine oil to scary stuff like cyanide and arsenic. The rule of "When in doubt, leave it out." applies here.

The final thing to watch out for is ANY plastic listed as static dissipative. This is usually pink, green, or blue in color. While not toxic in most cases, the static dissipative properties are achieved by bonding (no joke) pig fat to the polymer. The pig fat (read as Lard) attracts a microscopic layer of water to allow ESD. This can cause structural failure over time and makes a great place for harmful microorganisms to grow. As a result, these materials usually get additional chemical treatment to inhibit such growth which will leach into you water.

I personally would recommend staying away from polycarbonate. Polycarbonate is synthesized from bisphenol A monomers, which have seen a lot of media attention. Bisphenol A exposure has been correlated to feminization of animals, reproductive issues and other health problems in laboratory animals. Nearly all plastics will have some small amount or residual monomer left after polymerization.

Does anyone know if a domestic casting resin is a safe choice?

I'm an arts student and though I am well aware that the modelling clay I use is a toxic polymer based clay (completely out of the question for customising my axie's tank), I intend on making a mould and casting the sculpture in a safe plastic or silicone.

Any suggestions?

k. thanks for that guys. will have to be carefull. hope to be able to post some pics of new tank setup soon.:happy:

Stumpy said:

Does anyone know if a domestic casting resin is a safe choice?

I'm an arts student and though I am well aware that the modelling clay I use is a toxic polymer based clay (completely out of the question for customising my axie's tank), I intend on making a mould and casting the sculpture in a safe plastic or silicone.

Any suggestions?

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As long as you use an inert, stable and non-toxic release agent on the mold you do not have to worry to much (100 percent silicone spray is best). As long as the casting resin is a non metallic epoxy base, I would use it. Personally, I prefer alginate as a mold making media, however I do use moulage for one offs. I use modelling clays for pre-mold sculpting without issue.

of course allow excessive curing times and wash the finished item excessively before use to remove any residue. I am not sure if it is available outside the USA, but Original Dawn Dish detergent is probably the safest soap (followed up with OCD rinsing) to use for cleaning off projects before painting.

Abrahm said:

I personally would recommend staying away from polycarbonate. Polycarbonate is synthesized from bisphenol A monomers, which have seen a lot of media attention. Bisphenol A exposure has been correlated to feminization of animals, reproductive issues and other health problems in laboratory animals. Nearly all plastics will have some small amount or residual monomer left after polymerization.

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I feel Bi-A is a grey area, personally I swear by various polycarbonates like Lexan. All of the studies I have read are based on chronic oral ingestion (by rodents) of amounts that far exceed the residuals from a contact surface or atmospheric free chain monomers..
Here is some of what the EPA has on the matter, this is a good starting point for anyone interested in researching it on their own.

However, a grey area like this forces me to suggest "When in doubt, leave it out."

I just wanted to say this thread was very helpful =]
I've decided the theme for my tank is going to be cupcakes lol
I was wondering (this may be a dumb question) is glass safe?

Well, considering that most tanks have glass sides, I'm going to say yes. (Just as long as there aren't any sharp edges of course!)

Glass is a very safe material (aside from the possibility of breakage).