DIY Large Mosaic Mirror

This is a tutorial for making a high quality mosaic mirror.
There are a few things I would like to say before starting this. First of all, if you are going to go through the work of making a mosaic mirror, it's best to buy quality materials. I make my own ceramic mosaic tiles, but you can purchase tiles at a tile store and then cut them to size using snippers and a tile cutter. For a wall mosaic like a mirror, where the surface does not have to be flat, you can use irregular pieces of ceramic and glass, such as broken plates.
This mirror has a finished size of 1 meter by 60 centimeters, which is approximately 39" x 23".
I had a piece of 2 cm. thick multi-laminate board cut to size. I had a piece of 4mm thick mirror professionally cut at a glass shop to for the center: 75 cm x 35 cm, or 30" x 14". Do not skimp on either the board or the quality of the mirror.
The first thing to do is to varnish the board, both sides and the edge. The purpose of this is to prevent warping and bowing of the wood. I have read professional design blogs that have given tutorials for DIY mosaics that have left this out -- which is shocking. Anyone who has done a large mosaic and has the grout break up because the board contracted after drying will never make the mistake twice. So, no matter how small or large your project, if you are using a wooden base, always use multi-laminate and always varnish the board on all sides.
I then painted the back of the board and secured my mounting system to the board. Always figure out how you are going to mount your mirror in its end location BEFORE starting your mosaic. If you live in a home where the walls are constructed of drywall, you will need a wooden joist to mount a mirror of this size to or the weight will be too much. I am mounting mine into a brick and plaster wall, using four eyelet rings which I will later thread with reinforced wire as a hanging system.
I then measured off where the mirror should be mounted in the center of the board, and approximately where the tiles should end in order to give the inner edge of the mosaic a nice border:

I mixed tile cement into a paste. NOTE: With tile cement and with grout, I wear both a mask and gloves. The dust is toxic and irritating. It's applied with a putty knife...
... and then combed through with a putty comb. I am not sure what these are called in English, but it's a piece of metal with one edge cut out like teeth. They come in different cuts. I use a fairly small one for mosaics. You do this because the tiles take better and you use much less glue this way.
So then I began laying out the mosaic, section after section, in an abstract pattern. I am using all one color here, in different forms. The tiles are hand made and glazed silver bronze.

After mounting the tiles, I waited about two hours and then lightly touched every single tile to make sure they adhered. A couple had not, and I reglued them individually.

It is at this point that I mounted the mirror. I used extra strength industrial adhesive. It's expensive, but again, it's worth it for a project of this caliber. The reason I do this now instead of at the very end is because I want the mirror to be grouted into the moasic, not sit on top of the grout.

It was time now to let the entire mosaic dry over night, and to allow the glue to completely set. I covered the glass with protective paper and taped off the edges -- with packing tape, not masking tape. It's more water proof. Any extra glue that sticks to the mirror can be removed later with solvent.
That was yesterday.
This morning, I mixed the grouting cement. I wanted it to end up a dark grey, so I added a little black colorant to regular gray grouting cement.
The grout is applied with a putty knife, and pushed into all the nooks and crannies with a straight edge plastic grouter.

The grout is then wiped off, over and over, using fresh water and a sponge. NOTE: The water has to be changed continuously. Do not throw cement-loaded water down the drain. I place mine in a separate bucket, let it settle out and then dispose of the cement properly.
You have about a half hour to forty five minutes to really work with the grout. This is an uneven mosaic surface, so I had to dig carefully and polish every single piece manually.

Here's the mosaic as it is right now. It will need to dry over night. I will then apply a fixative to the grout and touch up the paint on the outer edges.

Once it is completely sealed and dry, I will thread the mounting wires, get it up on a wall and photograph it. It is to be the bathroom mirror for the new room.
Buon Lavoro!!