Chris in Canada wrote
To make very realistic mini stonework in any scale without messy moulds, multiple colour washes, egg cartons or (yuck) settling for printies, why not use the real thing? The coarse sand/gravel mix used in parks and school playgrounds is a terrific source of lovely mini stones of all varieties suitable for pathways, fireplaces, walls, house foundations etc... Is everything frozen solid and covered in snow? No problem. Many cities leave out the same sand mix in bins located near stop signs where the road is sloped. It's free, and they usually have a scoop or shovel head inside to use to fill your bucket. If you have no other need for traction aids, just return the unwanted material to where you found it, and if anyone asks what you are doing, just say you have finished building your
After choosing and washing off the stones you want, simply paint the surface you are "stoning" a light grey or off-white to resemble mortar for Justin Case, then glue the stones in place with a clear-drying glue. I use WeldBond as it seems to hold the stones in place better than most of the others. When the glue has dried, mix up some cellulose filler or spackle tinted with a few drops of craft paint and add "mortar" to the spaces between the stones using a finger, coffee stir stick or toothpick, depending on the scale you are working in. HINT: Only do small sections at a time as this stuff dries very quickly, and wipe off any extra mortar from the stones with a damp cloth.
If you want a finished-off look, use something with a rounded end (crochet hook or paintbrush handle, small stylus, dried-out marker) to go around each stone to smooth the mortar. Otherwise you can leave it as sloppy as you want, especially for garden walls. When was the last time YOU saw a cleanly mortared natural stone wall in RL scale?