Q: I have poured a concrete countertop and really want to preserve the
wonderful finish that came directly out of the mold. There are a few air bubble inclusions, but I intend to fill these with a mix of crushed turquoise and epoxy
for a great little detail. I don't want to expose any aggregates or lose the finish and textural feel that we experience now, which grinding may interrupt. How
can I achieve just the right amount of grinding that will still preserve the
current look of my concrete piece?

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Hopefully the following hints are helpful in this situation:

• To create a beautiful polished finish without exposing the aggregate, start with a 400-grit pad and lightly grind just until the melamine texture disappears. If you grind too deep, aggregates will begin to appear. If you under-grind, you will have rough areas on the surface that will be visible when viewed from
  acute angles.



• While grinding, periodically inspect the piece for rough areas. To do this, squeegee off all water and place a light source opposite you, squat down and inspect the entire surface from this sharp angle, looking for patches where the melamine texture
  is still visible.



• Depending on the hardness of the concrete you are polishing, you may find that the 400-grit pad is either too aggressive or not aggressive enough. If you discover you need a more aggressive grind, work with a 200-grit pad—conversely, if you need a less aggressive grind, work with the 800-grit pad.



• Once the initial grind is complete, you will probably have some air pockets or voids visible on the top surface of your piece. At this time, you can fill these voids either with a contrasting filler (such as the crushed turquoise) and a clear epoxy binder, or,
  for a more homogenous look, with a slurry color matched to the rest of your piece. We routinely fill these voids with our NeoMix Slurry Kit.



• Once the slurry, or in your case the turquoise/epoxy filler, has cured, continue grinding/polishing with the higher grit pads until you achieve the desired sheen. Once again, even with the
  higher grit pads, be careful not to grind/polish too deep or you will eventually
  expose aggregates.

As with any technique you are attempting for the first time, always pour a test panel that
you can experiment with before you take on your larger, more final project. This way you
can enjoy the learning process without the anxiety of "messing up" a piece for installation.

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