Improving 'floated' finish on concrete countertop

[Ilfornaio]

Re: Improving 'floated' finish on concrete countertop

I would not worry about the cracks if they are small (read hairline) just make sure the counter is well sealed. In cold weather ice is the biggest enemy of concrete. You stop the water, there is no ice.

[RichC]

Re: Improving 'floated' finish on concrete countertop

Thanks Deejay, I'll get the arch built and plaster the dome before I finish the counter. With the Irish weather I'm worried about water ingress

[deejayoh]

Re: Improving 'floated' finish on concrete countertop

I wouldn't cut into the cracks. It will just weaken that spot further and it will continue to crack. Cracks are part of using concrete. As long as they're fine lines, don't worry about it. I have a couple cracks in my counters at corners/joints. I never even think about them

[RichC]

Re: Improving 'floated' finish on concrete countertop

2 cracks!!! Neither appear to penetrate the slab completely. They're very fine cracks. Rather than try and work a slurry in, I'm going to run my angle grinder blade through it and then fill it. Hopefully this will avoid pockets of trapped moisture that might cause more damage when the frost hits it. Any reasons why this is a bad idea?

[stonecutter]

Re: Improving 'floated' finish on concrete countertop

When did you remove the forms? The reason for the questions...I suspect that the slab should have stayed covered and dampened longer. For larger format stuff like your pour, depending on the temperatures, two weeks would be my minimum before I stripped the forms.

Not much you can do now.

[RichC]

Re: Improving 'floated' finish on concrete countertop

Forms are off but haven't done any sanding. I'm guessing its just a shrinkage crack! I used slightly less latex additive than I did on the first attempt that I cut out.

[stonecutter]

Re: Improving 'floated' finish on concrete countertop

So, the mould forms are removed and you're sanding already?

[deejayoh]

Re: Improving 'floated' finish on concrete countertop

Damn hairline crack in the counter right at the front, the most visible spot. It doesn't appear to go right through. I assume the best solution us just working some slurry into it when I reach 800grit like with the small bug holes?

hmmm. Why is it cracking? Hard to say whether or not slurry will fix it or it will just reappear, best to understand why it might be cracking already

[RichC]

Re: Improving 'floated' finish on concrete countertop

Damn hairline crack in the counter right at the front, the most visible spot. It doesn't appear to go right through. I assume the best solution us just working some slurry into it when I reach 800grit like with the small bug holes?

[Greenman]

Re: Improving 'floated' finish on concrete countertop

Looking good. The chalk artwork is very special too.

[RichC]

Re: Improving 'floated' finish on concrete countertop

And some pictures! I'm fairly happy with the finish now. Will more than likely end up working in the slurry at 800grit as you guys recommended.
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[RichC]

Re: Improving 'floated' finish on concrete countertop

So today I made up a wet mix and rubbed it into any imperfections with an old T-shirt. Finish is quite good now. Can't wait to start grinding

[deejayoh]

Re: Improving 'floated' finish on concrete countertop

Tscarborough and Deejay oh, can you tell me more about the slurry? Is it just Portland and latex additive or should it include water? And sand? I'm considering using it before I start to grind. Should I trowel it in or what should I do?
Thanks

Richard

I used just portland and latex, a little bit of color (though the bug holes end up looking like aggregate). Tip I found somewhere was to put it on after you got to ~800 grit, as more holes magically appear as you start to abrade the surface. Use the 800 grit polishing pad at a slow speed to force the slurry into the bug holes. That seemed to work pretty well for me. I never notice anything that I missed.

[RichC]

Re: Improving 'floated' finish on concrete countertop

Tscarborough and Deejay oh, can you tell me more about the slurry? Is it just Portland and latex additive or should it include water? And sand? I'm considering using it before I start to grind. Should I trowel it in or what should I do?
Thanks

Richard

[RichC]

Re: Improving 'floated' finish on concrete countertop

Just realized I forgot to oil the shutter!!!! Damn! Any suggestions as to the best way to remove the timber and avoid damage?