I want to just "butter" up some flat pieces of flagstone, the biggest one square foot. Most less. I want to stick them to a cinderblock wall that I have powerwashed the paint off. I am also going to make some boxes out of cinderblock, and cover them with flagstone. I guess the mortar would be about 1/4" to 3/8" thick. Is that okay? Should I just use premixed mortar or thinset?
I have hundreds of pounds of flagstone left from laying walkways.
I live in Las Vegas, where it gets hot, is mostly warm all the time, hardly freezes, doesn't rain very often, if that makes a difference in the mixture.
I want to buy a small mixer, mix as much as I can use in an hour or so, then mix another exactly like the first. How long until I have to use up the mortar? Start from the top down on the vertical surfaces so I don't spatter the previously laid stones?
Thanks
Steve