QUESTIONI would love to have a mosaic cactus installed on my brick fence in my backyard. My friend can make one for me. However, before doing that, I want to know that once the project of making a mosaic cactus is completed and dried, is it safe to install it outside esp in very high temperatures as I live in Phoenix, Arizona? In other words, are mosaic tiles heat-proof or heat-resistant? Do the mosaic tiles need to be embedded in wood or metal? Any special glue for the heat-resistant or heat-proof? What else do I need to be aware of?
ANSWERANSWER - You didn't indicate if the mosaics are ceramic mosaics or glass mosaics.
Ceramic mosaics are normally produced at over 1200 degrees F. Normally custom ceramic tiles are dried and then fired in a kiln. So they can easily withstand 120 degrees F if they are installed correctly with adequate movement joints.
Glass tiles are also produced at high temperatures but they are more fragile as they inherently are under a lot of tension. So depending on the size of the mural and how it is installed they might be ok if done properly.
If you are talking sun baked tiles, then they will have a propensity to degrade when subjected to heat and moisture.
If you want to adhere the tiles to a brick substrate then you could use a polymer modified thin-set mortar that meets ANSI A118.4 or better as they will bond better and be more resistant to heat. Although the brick substrate has to be properly prepared and the tiles have to be properly installed.