| SILCONE BASICS: | | | | and is waterproof for freshwater or saltwater use. |
| Silicone rubber is a unique synthetic elastomer made | | | | You will note that plastic (which is made from oil) is |
| from a cross-linked polymer which is reinforced with | | | | not mentioned. RTV silicone is not useful for bonding |
| silica. Its characteristics are such that it provides a | | | | acrylic aquariums and the oils within acrylic will |
| balance of mechanical and chemical properties useful | | | | eventually cause peeling away (lack of adhesion). |
| for bonding glass aquariums (not acrylic). | | | | AQUARIUM APPLICATIONS: |
| The basic formula is: Me3SiO(SiMe2O)nSiMe3 | | | | RTV Silicones are useful in the construction of glass |
| RTV Silicones are the silicones commonly used for | | | | aquariums and sealing the joints in DIY wooden |
| glass construction and is often sold in Home | | | | aquariums. Silicone is NOT useful for acrylic aquariums |
| Improvement and Pet Stores (or online) | | | | as it will peel away over time due to the inherent oils |
| RTV Silicones consist of polydialkylsiloxane with | | | | in plastics. |
| terminal hydroxyl groups (groups made up of an | | | | Not all silicone formulas are the same, as stated |
| oxygen atom and a hydrogen atom connected by a | | | | earlier, Dow Corning and GE produce a RTV silicone |
| covalent bond), which are reacted with organosilicon | | | | that cures at an even and slow rate necessary for |
| (chemical compounds containing carbon silicon bonds) | | | | aquariums. Why is this important? Too fast a cure will |
| cross-linking agents. This operation is carried out in a | | | | not allow proper surface adhesion especially in |
| moisture-free environment and results in the | | | | important seams. It is also hard to work with in |
| formation of a tetrafunctional structure (A chemical | | | | building aquariums and the person needs to work |
| structure that possesses four highly reactive sites). | | | | very quickly (usually too quickly) for proper aquarium |
| Curing takes place when materials are exposed to | | | | construction. |
| moisture. Atmospheric moisture is sufficient to trigger | | | | Also you want to purchase pure 100% RTV Silicone |
| the reaction, and thickness should be limited if only | | | | as many (including ones produced by Dow Corning) |
| one side is exposed to the moisture source. Curing is | | | | have other ingredients for different applications such |
| also relatively slow, reliant on moisture ingress into | | | | as fiberglass. |
| the polymer which produces Acetic Acid vapors. | | | | A good example of a silicone you do NOT want to |
| Different formulas and (combined with temperature | | | | purchase is Dow Corning Marine Sealant which I have |
| and outside humidity) will affect cure time. Dow | | | | actually seen recommended for aquariums! This |
| Corning and GE have proprietary formulas that cure | | | | product is great for fiberglass hulls of boats however |
| at an even slow rate as compared to some cheaper | | | | it lacks the proper strength for aquariums due to |
| formulas, especially used in construction where this is | | | | added ingredients that allow for adhesion to plastic. |
| not an important factor. | | | | SUMMARY: |
| 100% RTV Silicone Rubber Sealant produces a | | | | Can you easily purchase the proper silicone at a |
| flexible, durable weather resistant seal between | | | | Home Improvement Store? The answer is yes, just |
| similar and dissimilar materials; RTV Silicone provides | | | | do not purchase anything other than 100% Pure |
| excellent adhesion to tile, glass, porcelain, ceramic, | | | | Silicone (color does not matter) and I strongly |
| fiberglass, non-oily woods, plaster, painted surfaces, | | | | recommend brand loyalty has there are good reasons |
| metal, many plastics, and rubber. It will withstand | | | | behind GE and Dow Corning patents. |
| temperature extremes from -60°F. to +450°F. | | | | |