Bag of play sand
3 to 4 cups of contractors sand (fine grade)
1 to 2 cups of Portland cement
Concrete fortifier (you can get this at Lowe's)
The size of the hosta leaf that I used was 13" long and 9" wide. You can also use rhubarb, burdock, gunnera, castor bean, caladium and elephant ear leaves. Make sure you cut the steam off your leaf.
Spread out a piece of plastic. I just cut open a large plastic bag from Target. Pour some play sand into a bucket and add enough water so the sand sticks together, like you were building a sand castle. Form a mound about the size of your leaf.
Once the sand is piled, cover it with a piece of plastic. You are now going to lay your leaf vein-side up on top of the plastic.
In a plastic container (I used a kitty litter box) mix three parts contractor's sand to one part Portland cement. I used 4 cups of contractors sand and 2 cups of Portland cement. Mix in a 1/4 cup of water and 1/4 cup of concrete fortifier, add slowly to the sand until it reaches the consistency of a thick brownie mixture. Mix in a little more water and fortifier if needed. Use your hands with rubber gloves to mix thoroughly.
Now pick up a handful of the sand mixture and plop in on the center of the leaf and spread to the edges. Smooth out so you get out all the air bubbles. Slowly build up the thickness so its between 1/2" and 1" thick over the whole leaf.
When your leaf is completely covered with the mixture, cover loosely with plastic. You don't want it drying to fast as it may crack. I let mine sit for 2 days before peeling off the leaf.
After your leaf has dried for a week, you can paint it or seal it. Or you can leave just as it is. I haven't decided if I am going to paint mine or not. It's still in the drying process.