Rocks that have been eroded smooth by water have a distinct appearance.
Ponds in backyards are typically made of plastic or fiberglass. A pond can be decorated with rocks to make it look much more natural. If you do not have access to real pond rocks, you can build fake ones. These rocks will have the feel and heft of real stone and you can customize them to the shape and size you need.
Instructions
1. Cut out pieces of foam into rock-shaped pieces with a saw. Make them slightly smaller than you want the finished rocks. You will be applying a thick cement coating that will increase their size.
2. Round and smooth the rock shapes with a rasp.
3. Mix a small batch of cement in a mixing bucket, following the mixing instructions on the bag. It should have the consistency of peanut butter.
4. Spread the cement over the surface of a few foam rocks with a small trowel. Work in small batches to avoid wasting cement.
5. Check the hardness of the cement every few minutes. You are looking for the point when it has almost hardened but can still be scratched with your fingernail.
6. Buff each rock smooth with a wet rag once it has reached the semi-hard state where it can be scratched.
7. Allow the rocks to completely harden. This will take a few hours.
8. Stain the rocks to the desired color with concrete stain. Brush the stain on, then wipe it off with a clean rag after a few seconds. If it is not dark enough, apply a second coat of stain.
9. Brush a coat of glossy cement varnish on the rock to seal it and give it a shiny outer layer.
