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View Full Version : Common aquarium uses for common plastics. These listed should be safe for aquariums.


MarkS
09/13/2003, 12:12 AM
My last thead on this subject was meant to be helpfull, but came across as more of a rant. Following a suggestion from Snailman (sort of...), I think this would be more usefull.

Here is a list of different plastics and some common uses. Not all are used in the aquarium trade directly. Any and all input on this subject would be appreciated as this seems to come up quite offen.

Anyway...

1.) Acrylics (brand name is Plexiglass)
Used to construct aquariums.

2.) ABS
Used in just about every aquarium product in existance from
glass aguarium frames to filters to pump and powerhead
housings. Typically black, but sometimes white.

3.) Vinyls
4.) Polyvinyl Cloride (PVC)
5.) Clorinated Polyvinyl Cloride (CPVC)
Used in most potable water supplies and in aquarium plumbing.
Typically safe unless heated to the burning or smoking point,
where (deadly) toxins are released. I believe this to be > 300°F.

6.) Polyethylene (PE)
7.) High Density Polyethylene (HDPE)
8.) Low Density Polyethylene (LDPE)
9.) Polypropylene (PP)
10.) High Density Polypropylene (HDPP)
11.) Low Density Polypropylene (LDPP)
Used in most potable water containers. Very easy to mold and
safe. FDA and USDA approved for potable water storage. Again,
safe until heated, though this seems to be the case with most
plastics. Caution needs to be taken when using a trash can for
water storage. Some manufactures add fungicides and mold
inhibitors which can leach out. Typically, the white, translucent
containers can be considered safe.

12.) Butrate
I remember seeing on RK2's web site that their 48" diameter
skimmer was made of this. Could be wrong, their site is
currently under remodeling...

13.) UHMW-PE or just UHMW (Ultra High Molecular Weight Polyethylene )
Chemically inert and very slick. USDA and FDA approved for food
contact surfaces. Used in bearings, cutting boards, chutes, etc.
Used as a bearing in kalk reactors where a magnetic stir bar is
used.

14.) Aceltal (Delrin)
John Guest fittings are made out of this.

15.) Polyurethane
The black plastic pipe fittings and hose barbs are commonly
made out of this.

16.) Polycarbonate (Lexan)
I do not know of any aquarium related use for this. Used in
some green house roofs. Lexan is commonly used in home
windows.

18.) Nylon
Used in bolts, screws, bearing, bushings, pipe fittings and hose
barbs. Very common in the aquarium trade.

19.) Teflon
Chemically inert and FDA and USDA approved for food contact
surfaces. Very slick and offen used in bearings. Used as a
bearing in kalk reactors where a magnetic stir bar is used. Also
used to coat the stir bar.

Thanks, jdieck. How could I forget teflon tape? :o

20.) Polystyrene
I don't know of any direct aquarium use for this. I believe it is
used to make styrofoam?? Could be wrong...

I would like some further input on each type of plastic. If I am incorrect on any point, please correct me. If there are further types of plastics that are safe for aquarium use, please post them along with why they are safe and some examples of their use (preferably in relation to aquariums).

Thanks,
Mark

jdieck
09/13/2003, 12:18 AM
Teflon: Do not forget the thread tape for fittings.

Lexan: Some UV shields for lighting fixtureas are made out of lexan instead of Acrylic as it has better UV protection capacity

jdieck
09/13/2003, 12:20 AM
I just remember another one. PTE (Penthaeritril Terephtalate) used to make transparent water containers (like the ones in purified water or coke bottles) I use them for my Kalk mix.

H20ENG
09/14/2003, 01:16 PM
Great list Mark!

Kegraties
09/14/2003, 01:26 PM
interesting but here is another note if the plastics you say are safe to use because they are fda approved for use in food processing . I wonder if you could use a fda approved epoxide paint for decoration in the tack or to paint the back of it. i work at sherwin williams and have orten wonderd about this.

jdieck
09/14/2003, 02:50 PM
I have read in another thread that some reefers painted their PVC spray bars black using one of the new canned paints for plastics without damaging effects just let it dry completely.
If painting the back of the aquarium I think a better looking finish is achieved viewing from the inside if the back is painted on the outside.

MarkS
09/14/2003, 06:47 PM
Thanks, I spent a good amount of time researching this.

What I was surprised about is the amount of plastics that are safe. The only one in the list that I am not sure of the polystyrene. I now know that it is in fact used to make styrofoam and foam board, but I cannot confirm it's safety.

What really surprised me was how easy it was to find this info. I looked through US Plastic's catalog to see what each different plastic product was made of and what claims the manufacturer made. Since US Plastic supplies many industries, including food processing, I am confident that the info provided by them is accurate. A 5 minute search of their site would answer about 99% of the questions that come up about plastic safety.

Some of the info, like the toxin release from PVC, is well known and has come up on this forum before. In fact, I think that this is the most usefull of all because the consequenses of not knowing this can be deadly.

I am still trying to find a link to RK2's web site that shows the big skimmer. I am certain that it is made of butyrate. The link I had was to a part of the site that most people could not go to directly. I am trying to find it, but it's going to take time.

Acrylics
09/14/2003, 11:40 PM
Originally posted by MarkS
I now know that it is in fact used to make styrofoam and foam board, but I cannot confirm it's safety.

It's fine in sheet form, fine particulates (dust) are quite nasty though at least to humans. I don't know of anything regarding safety issues relating to aquaria - my assumption is that it's just fine as styrene is one of the components in ABS as well as what they make model cars out of :) Eggcrate is also commonly made of styrene.


Some of the info, like the toxin release from PVC, is well known and has come up on this forum before. In fact, I think that this is the most usefull of all because the consequenses of not knowing this can be deadly.

It's not just from heat, folks should still be cautious when cutting - especially with table saws and other power tools which turn PVC to "dust". I know when cutting PVC for long periods of time I have to use a respirator to protect from the formaldehyde smelling cloud which will build up. There are actually quite a few horror stories in the plastics industry of this knocking people out.

To add to the list, possibly kinda obscure but...:
Kydex: and acrylic/PVC alloy used often in public aquaria to create "false backs". Not often encountered in the commercial end due to it's cost, but is safe and flame retardant too :)

EPDM (Ethylene Propylene Diene Monomer): Commonly used for gaskets in bulkhead fittings, o-rings, and pond liners

Viton (Fluoroelastomer): another material commonly used for o-rings

Neoprene (Polychloroprene Polymer): another material used for gaskets

Butyrate: Which you have on there already but as a BTW - it is FDA approved for dry food. Some of the RK2's tube may be made from this but the RK2's and Sanders' that I'm familiar with are made from clear pvc tube.

James

Addicted Reefer
09/15/2003, 01:41 PM
tagging along

MarkS
09/19/2003, 03:24 PM
Robert from RK2 just e-mailed me. I was wrong about them using buytrate. I don't know where I saw that. Anyway, they use either acrylic or clear PVC for their skimmers.

He also gave me some other interesting info:


Read your brief. Be careful with ABS and Polystyrene, they use metals as plasticizers. Neither are potable water approved. (I do not claim to be an expert in this field, consult the major mfg’s like Enron, GE etc.)

Robert


I am still not sure about the polystyrene, although I an certain that it is used to make styrofoam, which is used to make styrofoam cups, ice chests, and simular.

I do know for certain that ABS is used in almost all aquarium products. This is the first time I have ever heard of this. Can anyone else confirm this?

Mark

rsman
09/20/2003, 12:14 AM
YES

not all plastics are alike. depending on how the magic that is done to it to make the watever your buying is done it can contain things that will kill fishies :(

unfortunately I dont know the difference :( so past that I cant help you. I do know there is styrofoam that is not food safe. And I have heard from ppl in the know that some of the ABS plumbing parts can be dangerous, I myself stay away from any ABS that I dont know is food safe, and have seen the potable and non potable labels aplied to ABS

alexmarto
09/20/2003, 05:21 AM
What about NBR (Nitrile-Butadiene Rubber), is it safe too?

manklit

alexmarto
09/20/2003, 05:28 AM
I found the answer to my question. Sorry...

http://www.dichtomatikusa.com/handbook/4.pdf

manklit

murphd3
02/14/2004, 07:43 AM
How about structolene? This is the material my gutter guard is made of and I have not found out for sure if it is totally safe.

BTW, if it is, it is only $1.39 at big lots discount store. Seems like it would make a great snail-proof or jumping fish screen.

PaintGuru
02/14/2004, 09:08 AM
Like someone said, I don't think the real problem is the plastic itself, but with additives that are put in or solvents that could be trapped inside and leak out. Another thing to consider is degradation by UV and water. Nylon and epoxies do not like water at all. This is why you have to use "plumbers" epoxy to mount things, it has to be modified to last in water. I suggest not looking at plastics as a group (PE, PS, PVC, etc), but where the particular plastic you are using is being used (food, storage, etc.) and any other technical info about the manufacturing process.

Acrylics
02/14/2004, 01:54 PM
There are plenty of different types of plastic netting, Nytex being probably the most popular among aquaculturists.
There are netting materials made from, Nylon, polyester, polyethylene, and many other materials. Most of dirt cheap IMO.

James