Reef Safe Plastics

[Randy Holmes-Farley]

Very confused on this subject. As per everything I've read Not Aquarium related ABS is not considered food safe because it gives off a toxins. But everybody seems to recommend abs on various fish forums. Also I've been told Legos are made out of abs, so they must be food safe if toddlers put them in their mouth all the time.

So how can ABS be fish safe but not food safe?

Beyond the good explanation above, fish, inverts, and people all have different needs. Copper pipes are safe for people but not reef tanks, for example.

I'm also not aware of anyone who certifies a plastic as fish safe, and the concerns with things like long term exposure to plasticizers and other additives and residual monomers might be just as bad for fish, but these get far less attention and study than effects on people over years of exposure.

 

[FranklinDattein]

On a related token, I've recently started printing with Resing 3D printers and most of the resin manufactures provide rich SDSs. Unfortunately, the ones I came across are harmful to aquatic life.

On the FDM front, there is a handful of new plastics available and PETG is getting a lot of popularity, due to being strong as ABS, non-toxic and easy to print as PLA. It has become my filament of choice for Aquarium parts.

 

[kgk]

Bumping a super interesting thread. I print a ton of stuff, but never for my tank before. Going to build some canister replacements for my 4” filter socks, and was planning on using Amazon Basics PETG filament. I could also use PLA or ABS... ABS is a good option too.

Leaning towards PETG, mainly because I’ve done a bunch of PLA and ABS printing, but haven’t busted out the PETG yet.

 

[RichJSails]

Summarizing about 3D printed components... ABS and PETG, even PLA are all chemically stable in seawater at nominal pH levels. Someone mentioned the "magic of polymers", which is a good way to describe them. So, use of 3D printed components won't introduce toxins to the ecosystem.

However, there are several risks that need attention to limit the introduction of toxins. #1 - Pigments! Use clear or white materials (black ABS and PETG should be ok too). Whites are a formulation of inert oxides, typically titanium-dioxide and aluminum oxides, which won't create problems. Any other color is a gamble. #2 Sealants... FDM (3d prints) are porous, so if you need to make water-tight assemblies, stick to 2-part (aliphatic) poly-urethanes as a liner and be absolutely certain they are fully cured (heat cured at 40-45C ideally). Again, be careful of pigments. #3 Printbed adhesives or uncured SLA resinsmust be eliminated. Soak, wash, rinse... repeat and repeat again.

Notes: Over a long period of time, PLA will decay. The keyword, however, is LONG. Theoretically, some anaerobic bacteria might consider PLA as a food source, but only time will tell. Regarding "food-safe" issues, cope413 is spot-on. It's the porosity of FDM components that keeps the FDA nervous about the parts for food consumption. For our little ecosystems, they are just another home for nitrifying bacteria!

Urethane Resins - Read the MSDS. "Part-B"s tend to produce harsh histamine reactions similar to poison ivy. Please wear gloves if you handle these uncured chemicals.

 

[RichJSails]

Summarizing about reef-safe plastics and 3D printed components... ABS and PETG, even PLA are all chemically stable in seawater at nominal pH levels. Someone mentioned the "magic of polymers", which is a good way to describe them. So, use of 3D printed components won't introduce toxins to the ecosystem.

However, there are several risks that need attention to limit the introduction of toxins. #1 - Pigments! Use clear or white materials (black ABS and PETG should be ok too). Whites are a formulation of inert oxides, typically titanium-dioxide and aluminum oxides, which won't create problems. Blacks are carbon, but any other color is a gamble. #2 Sealants... FDM (3d prints) are porous, so if you need to make water-tight assemblies, stick to 2-part (aliphatic) poly-urethanes as a liner and be absolutely certain they are fully cured (heat cured at 40-45C ideally). Again, be careful of pigments. #3 Printbed adhesives or uncured SLA resins must be eliminated. Soak, wash, rinse... repeat and repeat again.

Notes: Over a long period of time, PLA will decay. The keyword, however, is LONG. Theoretically, some anaerobic bacteria might consider PLA as a food source, but only time will tell. Regarding "food-safe" issues, cope413 is spot-on. It's the porosity of FDM components and FDM machinery that keeps the FDA nervous about the parts for food consumption. For our little ecosystems, they are just another home for nitrifying bacteria!

Urethane Resins - Read the MSDS. "Part-B"s tend to produce harsh histamine reactions similar to poison ivy. Please wear gloves if you handle these uncured chemicals.​

 

[lordraptor1]

Of all the things listed in both posts, several are probably fine, but I think nylon would be a fine choice for most things.

Polycarbonate may be OK, but not if exposed to high pH, such as limewater/kalkwasser. PET may be similar.

The ABS is probably OK.

Polystyrene should be OK.

Definitely avoid the Bronzefill (copper), polyvinylalcohol (dissolves), pla (may slowly dissolve with or without bacterial action).

polycarbonate is fine it is also known as plexiglass or "acrylic" and is what a HUGE number of sumps are made from.

 

[DirtDiggler2823]

Just put together a 3d printer and I'm making stuff out of the PLA filament it came with, but I understand that material isn't suitable for use with my reef. I'm looking at ABS and PETG right now as materials.

 

[Randy Holmes-Farley]

polycarbonate is fine it is also known as plexiglass or "acrylic" and is what a HUGE number of sumps are made from.

Uh, OK. I'm aware of what these materials are. You seem to not be. Polycarbonate is not OK in all applications, hence my answer that it is not OK for high pH applications. It becomes brittle and can eventually breaks. Reefers have had such issues when using polycarbonate for limewater.

 

[lordraptor1]

Uh, OK. I'm aware of what these materials are. Polycarbonate is not OK in all applications, hence my answer that it is not OK for high pH applications. It becomes brittle and can eventually breaks. Reefers have had such issues when using polycarbonate for limewater.

if tehy were having issues with limewater it wasnt a high quality acrylic. most you should have from limewater is particulates being abrasive scratching or hazing. polycarbonate is also used for another application ( albeit much thinner) and that is rc car body shells. alchohol will sure screw up acrylic/ other things that might cause issues are dot 3 and dot 4 brake fluid, and some laquer thinners ( of course paint stripper will desolve it.

 

[Randy Holmes-Farley]

if tehy were having issues with limewater it wasnt a high quality acrylic. most you should have from limewater is particulates being abrasive scratching or hazing. polycarbonate is also used for another application ( albeit much thinner) and that is rc car body shells. alchohol will sure screw up acrylic/ other things that might cause issues are dot 3 and dot 4 brake fluid, and some laquer thinners ( of course paint stripper will desolve it.

OK, so folks should check with you first to see if their polycarbonate is high or low quality. lol

Ever try storing limewater in polycarbonate?

Polycarbonate is used for large (5 gallon) water bottles, like from Culligen. Some folks have used them for limewater reservoirs, only to have them crack and release a flood of limewater into their aquaria. Larry Jackson (famous old reefer) was one of those.

 

[AcanthurusRex]

Just put together a 3d printer and I'm making stuff out of the PLA filament it came with, but I understand that material isn't suitable for use with my reef. I'm looking at ABS and PETG right now as materials.

PETG; easy to print and relatively safe. You should use a stainless steel nozzle as the brass nozzles contain lead. I don't know how much nozzle material ends up in the print. I don't know if VCA uses a SS nozzle.
ABS is more difficult and emits fumes; I have never bothered with it. PETG os pretty much odorless.
I use black PETG; lighter colors look really back quickly.

 

[Randy Holmes-Farley]

polycarbonate is fine it is also known as plexiglass or "acrylic" and is what a HUGE number of sumps are made from.

Sorry, but that assertion of yours is just wrong.

Acrylic and plexiglass are polymethyl methacrylate, not polycarbonate.

 

[Randy Holmes-Farley]

if tehy were having issues with limewater it wasnt a high quality acrylic. most you should have from limewater is particulates being abrasive scratching or hazing. polycarbonate is also used for another application ( albeit much thinner) and that is rc car body shells. alchohol will sure screw up acrylic/ other things that might cause issues are dot 3 and dot 4 brake fluid, and some laquer thinners ( of course paint stripper will desolve it.

Right, because it is polycarbonate we are talking about, not acrylic.

 

[DirtDiggler2823]

PETG; easy to print and relatively safe. You should use a stainless steel nozzle as the brass nozzles contain lead. I don't know how much nozzle material ends up in the print. I don't know if VCA uses a SS nozzle.
ABS is more difficult and emits fumes; I have never bothered with it. PETG os pretty much odorless.
I use black PETG; lighter colors look really back quickly.

I think SS nozzles are a sound upgrade to make. Right now I'm printing the minor upgrades to help with the spool and whatnot. More substantial upgrades like glass print bed and ss nozzles are soon though.

 

[lordraptor1]

Right, because it is polycarbonate we are talking about, not acrylic.

polycarbonate IS acrylic LOL, another interesting fact in case you care, polycarbonate/plexiglass/acrylic, is generally referred to as lexan but lexan is the a brand name for polycarbonate acrylic. with that said, unless it is abrasive particles causing an issue with polycarbonate acrylic there should be no problems but polycarbonate is the same or really similar in terms of properties to "acrylic" and if you do a little research you will see "acrylic" and polycarbonate", are in the same class of materials. so if you are having an issue with polycarbonate you will have an issue with acrylic as polycarbonate is more resiliant to certain materials than "acrylic". polycarbonate will stand up to alchohol, acrylic wont, polycarbonate alse is more resistant to DOT3 and DOT 4 brake fluid for example 9 people use DOT 4 brake fluid to strip paint off of radioc control car polycarbonate body shells.

this make me think that whatever is being referred to as "polycarbonate" in this topic is low end or knock-off. now if you are buying your supply from lowes or home depot, just get the actual acrylic ( assuming your location hasnt wiped out their own supply making shields at the registers LOL.

 

[Randy Holmes-Farley]

polycarbonate IS acrylic LOL, another interesting fact in case you care, polycarbonate/plexiglass/acrylic, is generally referred to as lexan but lexan is the a brand name for polycarbonate acrylic. with that said, unless it is abrasive particles causing an issue with polycarbonate acrylic there should be no problems but polycarbonate is the same or really similar in terms of properties to "acrylic" and if you do a little research you will see "acrylic" and polycarbonate", are in the same class of materials. so if you are having an issue with polycarbonate you will have an issue with acrylic as polycarbonate is more resiliant to certain materials than "acrylic". polycarbonate will stand up to alchohol, acrylic wont, polycarbonate alse is more resistant to DOT3 and DOT 4 brake fluid for example 9 people use DOT 4 brake fluid to strip paint off of radioc control car polycarbonate body shells.

this make me think that whatever is being referred to as "polycarbonate" in this topic is low end or knock-off. now if you are buying your supply from lowes or home depot, just get the actual acrylic ( assuming your location hasnt wiped out their own supply making shields at the registers LOL.

I'm sorry, but you are misinformed and spreading inaccurate information. If you want to do that, please take it elsewhere. This is a science forum, and we will stick to scientific accuracy. Please stop misleading reefers with your lack of understanding. Polycarbonate is NOT stable to high pH.

This is a simple fact question that you have wrong. Perhaps in your world of 3D printers, folks sometimes use names incorrectly. We do not.

While who you or I are makes no difference to the truth of the facts, i want you to know that I really, truly understand polymer names. I am an expert in polymer chemistry (I have a PhD in physical chemistry from Harvard, have personally synthesized and patented hundreds of novel polymers, and some of my invented polymers have sales in the billions of dollars.

Just look up in your favorite polymer chemistry book what a polycarbonate polymer looks like,a nd what an acrylic polymer looks like. They are as different as polymers can be, and no one uses the names interchangeably.

Lexan is a brand name of one type of polycarbonate.

Plexiglass is one brand name of acrylic. Acrylic is usually short for polymethylmethacrylate. There are actually lots of acrylic polymers, but none are polycarbonate. That's like saying there are lots of types of apples, but none are oranges.

 

[Randy Holmes-Farley]

Everyone else who might want to know the difference between polycarbonate and acrylic can read it anywhere on the web, but wikipedia has fine entries for them:

Acrylic

Poly(methyl methacrylate) - Wikipedia

en.wikipedia.org

Poly(methyl methacrylate) (PMMA), also known as acrylic, acrylic glass, or plexiglass, as well as by the trade names Crylux, Plexiglas, Acrylite, Astariglas, Lucite, Perclax, and Perspex, among several others (see below), is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass.

The structure:

Polycarbonate

Polycarbonate - Wikipedia

en.wikipedia.org

Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. ....... Polycarbonates do not have a unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA).

The structure:

Polycarbonates

 

[lordraptor1]

i have tried hundreds of chemicals over the years to strip paints from both and i can tell you for a fact that the polycarbonate withstands the harsher chemicals, i can also attest to polycarbonate containers having NO affect on PH or anything else having used containers made out of polycarbonate a few times over the course of the past several years.

so again YOU are the one spreading false information, and if it is really that big of a concern then maye you shouldnt be looking at acrylic or polycarbonate in teh first place and should instead be looking into a glass container.

 

[Randy Holmes-Farley]

i have tried hundreds of chemicals over the years to strip paints from both and i can tell you for a fact that the polycarbonate withstands the harsher chemicals, i can also attest to polycarbonate containers having NO affect on PH or anything else having used containers made out of polycarbonate a few times over the course of the past several years.

so again YOU are the one spreading false information, and if it is really that big of a concern then maye you shouldnt be looking at acrylic or polycarbonate in teh first place and should instead be looking into a glass container.

I said you were misinformed. I did not call you names. Name calling is not allowed.

You seem to be confusing product properties with chemical structures.

Anyone can look up polycarbonate and see that it says it is unsuitable at high pH.

PMMA (acrylic) gets an A rating in 10% sodium hydroxide, meaing it is resistant:

https://marketing.industrialspec.com/acton/attachment/30397/f-006b/1/-/-/-/-/acrylic-pmma-chemical-compatibility-chart-from-ism.pdf

Polycarbonate gets a "not resistant" rating in 5% sodium hydroxide:

Chemical Resistance Chart For Plastics | Plastic Chemical Compatibility | Curbell Plastics

Chemical resistance plays a big factor in material selection. Use Curbell’s Chemical Resistance Chart to determine plastic chemical compatibility.

www.curbellplastics.com

 

[Florida Sunshine]

Based on my experiences with Randy in the past I will say that this statement sums it all up.

"you sir are incorrect and if you may wish to look in a mirror prior to making such accusations. you clearly are the one that is uninformed, i have not only been using both types for years but have also on occasion worked at plastic supply houses and i can tell you YOU sir are wrong unless somethign has changed in the last 5 to 8 years polycarbonate and acrylic are the same stuff with only minor differences i have polycarbonate that will withstand lacquer thinner while "acrylic" does NOT"

The key phrase being "polycarbonate and acrylic are the same stuff with only minor differences" Randy as a chemist includes what you term "minor differences" as "differences"
Yes the use of common names does make it rather confusing which is why I trust the man who actually understands the molecular reactions that I do not.