Post by Carl on Jan 2, 2019 10:20:20 GMT -5
I've updated the Aquarium/Pond Answers article: Aquarium Silicone, Tank Repair, Applications, DIY, How To Use
Here is an excerpt:
"AQUARIUM APPLICATIONS:
100% "food grade" RTV Silicones are useful in the construction of glass aquariums and sealing the joints in DIY wooden aquariums. As noted earlier, Silicone is NOT useful for acrylic aquariums as it will peel away over time due to the inherent oils in plastics.
Why is this important?
As I noted in the Basics Section, too fast a cure will not allow proper surface adhesion especially in important seams.
It is also hard to work with in building aquariums and the person needs to work very quickly (usually too quickly) for proper aquarium construction.
Not all silicone formulas are the same, as stated earlier, Dow Corning, AAP, and GE produce a RTV silicone that cures at an even and slow rate necessary for aquariums. It is also noteworthy that most silicones labeled as 100% RTV, are still not food grade.
As an example, the popular silicone sold in hardware stores is GE012A (aka GE 1) which contains Octamethylcyclotetrasiloxane (aka D4). GE 1 or GE012A has D4 at 1-5% by weight.
Ever have one tank that nothing survives in? It probably had that 5% or worse of D4.
AAP/ASI Silicone has D4 @ .2% or less by weight.
Studies on D4 have shown extremely low quantities (we are talking µg / liter) can limit growth, reproduction, and decrease health in fish and it isn't good for us either. It also bioaccumulates. Once these silicones cure the risk is lessened, but D4 DOES still leach into water and even fatty tissues.
These hardware store 100% silicone contain D4 that is bad for your fish at low doses, although not immediately fatal at the levels leached into your aquarium. Just like you can drink water with high levels of lead or even arsenic for years and have no trouble, but eventually.
Yes there are many studies that show D4 leaches from silicone. None that we know of that involve aquariums though. Most studies are medical devices, implants, IV tubing, baby bottle nipples, water storage, etc. Guess aquariums aren't that much of a priority for toxicologists? But then you gotta follow the money."
Carl
Here is an excerpt:
"AQUARIUM APPLICATIONS:
100% "food grade" RTV Silicones are useful in the construction of glass aquariums and sealing the joints in DIY wooden aquariums. As noted earlier, Silicone is NOT useful for acrylic aquariums as it will peel away over time due to the inherent oils in plastics.
Why is this important?
As I noted in the Basics Section, too fast a cure will not allow proper surface adhesion especially in important seams.
It is also hard to work with in building aquariums and the person needs to work very quickly (usually too quickly) for proper aquarium construction.
Not all silicone formulas are the same, as stated earlier, Dow Corning, AAP, and GE produce a RTV silicone that cures at an even and slow rate necessary for aquariums. It is also noteworthy that most silicones labeled as 100% RTV, are still not food grade.
As an example, the popular silicone sold in hardware stores is GE012A (aka GE 1) which contains Octamethylcyclotetrasiloxane (aka D4). GE 1 or GE012A has D4 at 1-5% by weight.
Ever have one tank that nothing survives in? It probably had that 5% or worse of D4.
AAP/ASI Silicone has D4 @ .2% or less by weight.
Studies on D4 have shown extremely low quantities (we are talking µg / liter) can limit growth, reproduction, and decrease health in fish and it isn't good for us either. It also bioaccumulates. Once these silicones cure the risk is lessened, but D4 DOES still leach into water and even fatty tissues.
These hardware store 100% silicone contain D4 that is bad for your fish at low doses, although not immediately fatal at the levels leached into your aquarium. Just like you can drink water with high levels of lead or even arsenic for years and have no trouble, but eventually.
Yes there are many studies that show D4 leaches from silicone. None that we know of that involve aquariums though. Most studies are medical devices, implants, IV tubing, baby bottle nipples, water storage, etc. Guess aquariums aren't that much of a priority for toxicologists? But then you gotta follow the money."
Carl
