SilFlex RTV 7500 Silicone is used by The Glass Block Supply Company to bond the glass block to each other and other materials including our vinyl dryer vents. Designed for aggressive adhesion to PVC, concrete, glass, aluminum, painted surfaces, wood, plywood, stucco, building paper, window wrap, fiber cement, brick, stone, steel, ceramic, porcelain, masonry, plus many other common material surfaces. It meets the standards to be used both internally and externally.

The SilFlex RTV 7500 is completely waterproof, sun fade resistant, and non-flammable to provide the utmost satisfaction when using this product. It will provide years of worry-free performance against rain, sun, and temperature extremes.

SilFlex RTV 7500 meets a number of American Architectural and US Specifications, making it safe to use in your home or business and meet Green Business Standards. This one part silicone is VOC compliant once fully-cured. SilFlex creates tough but flexible bonds that will move and vibrate with the structure. This multi-purpose silicone will be tack-free in 25 minutes and fully cured in 30 hours. One tube of silicone covers approximately 5-7 glass block. The SilFlex RTV 7500 can be applied using a typical caulking gun for a quick and easy application.


You may be asking yourself, why should I use silicone instead of mortar? Keep reading to learn more.

Using silicone for in your glass block projects provides for a lighter and brighter application in any part of your project. A silicone joint is typically smaller and allows for more light to pass through the windows and panels. A smaller joint between the glass blocks will create the all glass look that many desire. The smaller joints make for a more snug and secure fit into window frames and smaller openings. Not only can this silicone be used between the glass blocks in the windows, it can also be used to seal joints between windows and trim. By sealing these joints with a waterproof silicone, there is a lower risk of water damage. In bathroom applications, the use of silicone requires less maintenance than mortar applications. Mortar typically requires a waterproof sealer to be applied every couple years, this is not required with silicone. Unlike mortar, silicone is not a porous material; meaning the silicone will hold moisture that can cause mold and mildew to grow.



Safety Data Sheet

Technical Data Sheet