After the concrete has cured for about 4 days, you can now begin removing the liners and the mold. Once they are removed, go over it with some fine grit sand paper, which should help expose any remaining bug holes that will need to be filled.
Then hit it with a slurry coat, a very fine cement that helps fill the small holes and gaps created during the drying process. You can use pure portland cement for this or buy a slurry mix. Go over the surface of the sink and ensure that these holes are filled and the surface is smooth.
Use a turbo cup wheel on an angle grinder to grind down and clean up the dried concrete if you need to. Mine was a little uneven on the bottom of the sink itself so I decided to clean it up a little bit. This is a good time to deal with any balance issues or imperfections you might come across on the underside.
Lastly, add several coats of concrete sealer if you choose to. You can also add an acid stain to give your sink a different colored look if you choose to, but if you’re like me, you may choose to keep the raw concrete look.