Mosaic onto plaster!

First, you are going to want to prep the heck out of your plaster beast. Cover the thing from head to toe with thinset and fiberglass mesh. Let it dry overnight and again cover it from tail to head with thinset and fiberglass mesh. Even the underside! This can be very time consuming. I prep the underside because if you want this thing to survive outdoors, you need to protect the very thing it sits on. I even tile the bottom as you'll see later...

How to Mosaic onto Mesh Part III

Here is a section featuring a woman shopping downtown. Once you have your image under plastic pulled tight, and mesh laid over that, then you can begin nipping tile and gluing it onto the mesh. I printed out 8" x 10" sections in color to refer to because in certain parts it's hard to see what's going on in black and white. I use Weldbond glue, fiberglass mesh, and frost-proof porcelain tiles and stained glass because this is going on a buildings exterior and you need to use exterior grade materials. I used a black Sharpie pen to outline on the mesh where I will be cutting the mesh into pieces. That way I know not to put a tile over the line so I can cut it out later. From what I hear, the pieces should not be larger than 18" or the weight of the tiles will pull the mesh down if you're adhering it to a vertical surface.