What is an RTV Silicone?
RTV stands for room-temperature-vulcanizing, meaning that the silicone begins curing as soon as it is exposed to the moisture in the air. While many sealants are room temperature vulcanizing, products can vary in price and quality, which essentially depends on the purity of the product. 100% RTV silicone sealant is a completely pure product where extended silicone sealant is diluted.
The Difference Between RTV Silicone Sealant And Extended Sealant
All rubber that cures at room temperature is considered RTV, but not all RTV is created equal. 100% RTV sealant differs from extended in that extended is mixed with or “cut” with various types of oils and solvents, making it less pure. These oils and solvents affect the performance of the sealant.
Why Do Manufacturers Cut Sealants?
As much as this initially seems like a sneaky manufacturing trick, there is a definite benefit to the consumer. Cutting sealants lowers the cost of production. This is good for you because lower production cost means lower sale price. While extended lags behind 100% RTV in terms of performance, its lower price is undeniably attractive. The simple truth is that some projects just don't need extremely strong adhesives, and diluting the silicone is a good way to make your sealant cheaper for these kinds of projects.
Performance Of 100% RTV vs. Extended
100% silicone will perform better than “extended”. Pure silicone will have stronger adhesion, less shrinkage lower temperature application, and stronger resistance to weathering. If you are using your silicone in an oven or on a rooftop in Florida, 100% RTV will handle the heat much better. If very heavy materials are depending on your sealant to hold, 100% RTV will supply that security.
When Should I Use 100% RTV and When Should I use Extended?
Using a cheaper sealant isn’t a bad idea for some projects. If your project doesn’t require a strongly adhesive or temperature resistant sealant, there’s no reason not to go with a extended silicone, a less expensive product. However, if your silicone sealant is going to be under continuous stress in regards to weight or temperature, going with a stronger sealant is recommended.