I made my concrete countertops 8 years, poured in a mold and then put into place.  Followed the Cheng instructions, used the Cheng line of products.  I'm about to resurface again and need some advice about those damn pinholes!  The slurry didn't fill them; I tried the squeegy, I tried doing it by hand, I tried a lot of other things too.  Ugh!  Now Cheng has another slurry product --Surecrete Xtreme series slurry that promises it can fill those holes.  Has anyone used it?  I have a feeling that those pinholes are only the tip of the iceberg and that they are just the top to a larger hole and the air inside can't get out so nothing can get in.

My counters are 2 inches thick.  If I ever do this again, and I probably won't, I would make my initial pour under an inch and vibrate that, and then add the rest of it.  Two inches of concrete on top of air bubbles is a lot of weight, so how can air bubbles rise under all that pressure?

Another question--I'm going to lightly grind the counters with the finer diamond pads.  Should I reseal too?  How penetrating is the [Cheng] sealer on hardened concrete?

Thanks for reading.  I'll post pictures of my counters next week.  

Sarah

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If you didn't vibrate the counters during casting you more than likely have pin holes throughout the concrete. The wax you used as a mold release might have had petroleum which can cause air to stick to the mold surface. Even if you fill the visible holes eventually new ones will open up that lie just below the surface with wear and tear. You could try mixing dry cement and pigment in the proportions of the original mix design in a coffee grinder and filling the holes dry, then misting the counters and going over it with a wet grout and polishing it. You would probably be better off making sample molds and fine tuning your mix design/casting technic and just replace them.
I use a techniques I read about years ago they called it "powering out pinholes". Run a 200 grit pad on your polisher, add a blob of slurry to the surface and run your polisher over the surface on LOW till the slurry starts to tack up. You'll see the holes fill and you'll get a nice even coat of slurry. I've been experimenting with "Grind-n-fill" I use it on floors. It turns the slurry from grinding into a cement paste that will get hard and fill the holes. Either way at least it's your house, it can get messy! Good luck!

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