We just looked at a job and noticed the cement joints between the stone.
The person who (The owner didn't know. He probably was a little embarrased to admit that he did it.) cut out and re-tucked the joints using some type of epoxy in the cement.
Epoxies can make the joints stronger, but they don't look that good.
Take a look!
You're better off cutting the joints out and re-tucking the joints in with Portland Type I-II cement.
To get a smooth finish, you need to sponge the joints using the sponge below.
The epoxy in the cement is strong, but isn't needed. Just use Portland Cement.
We use an epoxy called Laticrete for Brick Pavers. But that is only underneath the bricks and not to fill the joints.
We also have a page loaded with other great tutorials for installing stone. I will also be researching more topics to help you beautify your home and garden with stone. Just put in your name and e-mail below and you'll get some great tips and tricks!