Glass block mortar is just one way to install glass blocks. However, it’s not the only way. There are alternatives to using glass block mortar.
An excellent alternative to glass brick mortar is a metal grid system. This is ideal where you have an existing reinforced opening, such as a window, where you want to put a glass block. All you have to do is buy a grid in the appropriate size and fit it into position in the frame, securing it with screws. From there you only have to put the glass blocks into the squares on the grid. There’s nothing else needed, as it’s a snap and lock system. It couldn’t be simpler to use, and the glass blocks stay in place without a problem.
The other main alternative to glass block mortar is using spacers and a clear caulk. With this, you use spacers to separate the blocks from each other, which means they remain an equal distance apart. The lowest blocks rest on a bed of clear silicone caulk. The caulk is used to secure the glass blocks along with the spacers until you have the area filled with the blocks. The clear caulk keeps the clarity and transparency of the line.