My soap dish got broken, and I'm trying to replace it. (see picture) behind the soap dish is the excess tile set, mesh, and the concrete backer board. I'm not sure if I should chisel away the the concrete backer and the meshing and stuff, as I'm a tiling kindergardener. I already started chiseling away some of the backer. if i place the new dish in there, it doesn't fit in the hole without the leftover stuff getting in the way. can someone give me some help/encouragement that I'm not going to ruin my tub wall?
Get a hammer and a scraper like a 5 way tool or a small chisel. Just remove the thinset but leave the cement board. it wont be easy because you dont have a lot of room to work in the opening but it looks like its not an overabundence of thinset to deal with. There are specialty tools that would work great but not the kind of thing a rental center would carry so unless you know someone who owns one, the old method will have to do. Its Ok if some of the top layer of cement board comes off but you dont want a gaping hole there, the soap dish needs a solid backing for the thinset to bite and hold while it dries. Dont use glue or mastic, rather use modified thinset that comes in a bag and mixes with water. Use tape to hold the dish in place while it dries overnight.