BASIC MOSAIC METHODS
The Direct Method
This is when you attach mosaic tiles or tesserae (fancy word for small pieces) directly to a panel or board of some type so that you can see exactly how it is going to look as you create it. It need not necessarily be a flat surface, you might be applying mosaics to a lamp base, sink, or you car. Unless the tiles or pieces you are using are consistent and perfectly flat, it is not the best method for a floor where unexpected unevenness might trip someone.
If you are working on a figural design, you can sketch the basic outlines on the surface first. This is how I made the mosaic glass tile panel in my kitchen, using a Sharpie pen to outline my basic shapes before I glued down my tiles one at a time. Then grouted the panel when all the tile were firmly attached.
The Indirect Method
This method is recommended where a very flat surface is necessary such as floors and tabletops. One advantage of the indirect method is that the mosaics can be created off site, in a studio or sitting by the pool! Using the indirect method, you glue the FACE of the tile or mosaic piece with water-soluble glue to craft or heavy paper, leaving the necessary spaces for grout later. The tile-on-paper is then pushed into a bed of thinset mortar, allowed to set and the paper is then wet and allowed to soak until the paper is easy to remove. It can be difficult to imagine how a large mosaic made of many interlocking sections will look in the finished state.
Mosaic Made on Mesh or Netting
This is the method I like by far the best. I'll describe two ways to go about it.
Method one: Sketch out your basic shapes on full sized paper---backwards. This does not mean to stand at a drawing board backwards using your arms behind your back. This means, to reverse the design as in a 'mirror image'. Use a bit of tape to stick it down to your work surface. Over that, put a piece of clear Contact 'Paper' with the sticky side UP. I have also used clear plastic with 'removable' adhesive designed to be used as textbook covers. You want just enough stickiness to keep your mosaic pieces from sliding around, but not so much adhesion that it is difficult to peel off later. You then, put your mosaic pieces FACE DOWN on the sticky plastic, following your easy to see sketch underneath. Next, you lay a piece of netting over the completed mosaic and apply strong glue through the netting onto the backs of the tiles or mosaic pieces. You want to be sure to not use so much glue that it runs between the mosaic tiles or pieces and fills in the grout areas. I have read that you can soak the whole piece of net in a glue-bath and then press it against the backs of the tiles, but my work has required a more heavy duty and waterproof approach. On the sections of mosaics that were to be applied to my shower walls, I simply, quickly, put a dab or dollop of glue on each tile back through the netting, rubbing out any lumps or bumps before it was set. I used Goop adhesive. It is available in most all hardware stores and crafts depts. and is unbelievably strong & waterproof when cured. Flip the mosaic section over and peel off the clear adhesive sheet when the glue is set enough to handle.
Method two: Sketch out your basic shapes in your design on a piece of full sized paper, just as you want it to look, not mirrored image. Put down some waxed paper or clear plastic that you can see through, is fairly heavy and can be disposed of later. On top of all that, place your netting. Use small pieces of tape to secure everything to your work-surface. Attach your tiles directly, putting a bit of heavy glue, like my favorite, Goop, on the back of each tile or mosaic piece. When you are done with that whole section of the design, or whole mosaic if it is small, wait until the glue has set just enough to handle and flip the whole thing over and peel off the clear plastic or wax paper quickly. Leave the mosaics face down on a perfectly flat surface until the glue has finished curing or drying. Don't forget to peel that backer plastic or wax paper off before the glue sets or you have a real problem on your hands. I know, been there, done that.
Here is a method I have read about but not tried myself. It looks like a good method for stepping stones, small countertops or small table tops, where you create not only the mosaic design, but the actual stepping stone, countertop or table top in the process. It produces a nice level surface.
Build a form, (a mold) the exact shape & thickness of the finished piece you want. Make it so the side rails can be removed later... use screws, not nails. Or some clamp system if you plan to make several of the same shape. You'll want it to be like a shallow tray, the thickness you need. Sketch your design out mirror-image on a piece of heavy paper slightly smaller than the bottom of your mold. Stick your individual mosaic pieces to the heavy paper face down with water soluble glue. When the mosaic is dry, mix grout and push grout into the spaces between the mosaic tiles or pieces using a rubber grout squeegee (don't you just love the spelling of that word!) or rubber spatula. Work it in the cracks from a diagonal approach. Clean away excess grout, but don't worry about totally cleaning it (it is the back after all).
Using petroleum jelly or some mold release agent cover the insides of your form/mold. Place the completed mosaics in the form/mold paper side down. Mix up some concrete mix, in a bucket, adding water until the mixture is workable. Or use portland cement one part to 3 parts sand. You can also add a color tint if you want. Trowel the mix onto the grouted mosaics, over the edge and into all parts of your form/mold. If your piece is large, only put enough cement mix to come half way put he depth of the form and lay a piece of expanded metal lathe or chicken wire to reinforce it into the mold. Fill the frame/mold to the top with the remaining cement mix. Tamp it down well, smooth off the back and wrap in plastic to cure for a week or so. At least a couple of days. Unscrew the sides of the form/mold. The mosaic slab can now be removed. Placing a board on top and sandwiching the mosaic slab between the board and the mold back as you flip it over helps support it. Right side up, the paper will be facing you. Dampen it to disolve the glue you used to attach the tiles. Carefully peel it off. Once the paper is removed, you may need to re-grout the mosaics from the front to fill in any voids. Remove any extra grout from the face of the mosaics. Wrap the completed piece in plastic and allow it to cure for a few days. Your completed mosaic slab will now be weatherproof. If yur piece is to hang, don't forget to add a piece of wire on the back for hanging when the cement before the cement mix is set.
Additionally, sites on my links section have instructional pages.
My Indoor Mosaic Tile Cuttin' Box
I live in a warm weather climate and tend to do my mosaics that involve cutting tiles outside on my porch so I can Dustbust vacuum up the larger glass shards and any tiny bits of glass that fly about end up in the thick grass and are no problem. But this has been a very cold winter (2003) so I have made myself a cuttin' box to use inside to contain the flying bits of glass and keep them from getting all over the room & me.
I took an empty cardboard box that a used inkjet printer had been mailed to me in. I cut a large opening on one of the nice flat side. Over that I put two sheets of nice stiff clear plastic that I had actually been the backer sheets from some sticky peel-off laminating plastic.( I never throw anything away ! ) I used clear box sealing tape to securely attach the clear plastic on all sides. You can see the seam in the middle of the clear look-thru top where I pieced the two 8 1/2 x 11 sheets. Then I cut two holes on the side just large enough for me to put my hands through and slip in my tile nippers. The white patches are where I cut my first holes too high and couldn't reach the bottom of the box to pick up glass that fell. I went all around my box's seams with clear tape to be sure no tiny holes at the corners would let tiny pieces of cut glass fall out. I also taped down the interior box flaps so glass wouldn't slide up under them. So now I can hold a tile or piece of glass in one hand and use the tile nippers to cut it with the other one while I stay inside and keep warm.
My next improvement is going to be to make a flap I can open and close to get the Dustbuster mini vac in there to remove the bits of glass that accumulate. Might use velcro to make sure it closes securely. Meanwhile, I can hold the hand hole side down and shake the bits out onto newspaper or over a garbage can liner.
Total cost --ZERO $