Available at Crafts stores (Michaels, Hobby Lobby, etc.) Mix two equal parts (similar to epoxy), stir for 2 minutes or so, then pour into your area. As it comes, it will cure to a CRYSTAL CLEAR, ROCK HARD finish. It says to do successive pours of 1/8 inch if you want a deeper surface, but I’ve done 1/4 inch without any problems.
Cure time varies on ambient temp - I’ve found at 70 degrees it takes up to 6 hours, though…you will notice some very small bubbles will float up to the surface after several minutes - don’t panic, just exhale over the surface and they magically disappear - pretty neat! If you can’t get close enough, instructions advise using a propane torch, fanned across the surface - haven’t tried that since my table is so small I can easily blow over any part of it.
If you want ripples or waves on your surface, simply wait to JUST BEFORE it hardens and drag a fork, small dowel, or whatever you want through it. If you do this too soon, it will flow back to a mirror smooth finish. Since your conditions will vary, you’ll just have to experiment.
But for glass smooth water OR ICE, just pour, remove the bubbles as mentioned above and wait. And if you mess up, just re-pour on top of your surface and try again. TIP: You might not want to completely fill your cavity or area in case a re-pour is necessary. MAKE SURE YOUR AREA IS LEVEL AND IS SEALED TO PREVENT “LEAKAGE”.
There are other materials out there to simulate water/ice, but I know this one works.