I always troll through art supply stores.
The other day there was a sale for a product that looked alot like Vallejo Lava.
A jar of pumice paste used to add texture to canvas.
It comes in Fine,Coarse,and Super Coarse
This stuff dries to a rock hard surface and is sticky enough to stick to any base.
This is a great way to make realistic looking slotta bases without gaps.
Take a small amount of paste and a little paint of your desired color,I am using Charadon Granite.
Mix thoroughly and spread onto base.
While wet sprinkle a little bit of hobby sand to add varied texture and add a small rock if you like.
Let dry overnight and you have a great base ready to use.