Making Mosaic
Stepping Stones
Here, the mold is greased & the glass is placed inside with the good side down. The glass is held in place with a film of sticky shelf paper.
The mortar is mixed a little on the wet side and spooned in, edges first, to keep the pattern from shifting.
Continue filling the mold making sure the mortar fills the spaces. A little hard on your "manicure," hands work best. Pat down & level it up. You will begin to see some bubbles working their way to the surface.
Cut an old piece of fencing or whatever you have lying around that will offer strength and help "marry" the mortar to the concrete which will come next. We've used 1/2" size & up hardware cloth for this too.
Mix the concrete stiffer than you did the mortar (less water). With concrete, the thicker it is in the beginning, the stronger it will be when dried. Again, start at the sides...
...and slop, drop, plop the concrete mix into the mold. Start patting it down & leveling it off-- making sure you've left no voids along the sides. You will feel the stones in this mixture being driven down as the water works its way up.
You can gently lift the corners and drop them to help drive the air out. You'll see the small bubbles come to the surface. Smooth it off to suit yourself (I leave mine pretty rough)...and wait at least 36 hours!
Caution, wet concrete! Wait a couple of hours then go ahead... write your name and date it!
Tip out time! Carefully turn the mold over and work the sides free from the stone. If you've greased it well, it will slide right off. --Don't panic, it won't always look like this.
Work up a corner of the sticky shelf paper and pull it off.

Now you've got to get all that runny mortar off of it. Rubbing with a wet towel, sponge or scouring pad (without detergent), remove the mortar that overwashed the glass area. It should come off fairly easy even after 36-48 hours. You'll find you can rub pretty hard, use a fingernail here and there or a razor blade window scraper to get it cleaned up. After all this sloshing, it will still look wet, and should be left to dry a few more days before you "step" on it. Unless you've colored your mortar, it will look almost white when dry. Congratulations!
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