Concrete countertops

[Ruffdaddy]

So I made some concrete countertops to surround my smoker and a few other things on one side of my patio...and as expected the countertops came out of the form with little voids from trapped air.

I actually like the look and so does the wife so I actually held off on the slurry fill step and want to move straight into a sealant.

Is there any reason (other than debris accumulation) that I should fill in the voids? Or should it be good to go as is?

[Stangs 4 Life]

During winter, if water freezes in those voids, the surface will likely be damaged. Water expands when it freezes.

[Ruffdaddy]

During winter, if water freezes in those voids, the surface will likely be damaged. Water expands when it freezes.

Fair point...I dont want to save the forms over a season to find out and I dont ever want to build them again so i may just patch out of caution.

[bcoop]

We have concrete tops in our bar. We only got the pockets on the edges where it met up with the form. We skipped the fill, and went straight to sealant. It has held up just fine.

If I had voids in the top, I would fill them because it would drive me nuts for it to not be smooth. It also gives a place for water to collect, which will promote mold growth, and if food collects in there you'll get all kinds of fun bacteria growth as well.

[Ruffdaddy]

We have concrete tops in our bar. We only got the pockets on the edges where it met up with the form. We skipped the fill, and went straight to sealant. It has held up just fine.

If I had voids in the top, I would fill them because it would drive me nuts for it to not be smooth. It also gives a place for water to collect, which will promote mold growth, and if food collects in there you'll get all kinds of fun bacteria growth as well.

Mold and bacteria growth definitely give a second reason to fill. I want the outdoor kitchen to be very low maintenance...and cleaning the voids that may start to accumulate crap sounds no fun...especially if I need to sanitize.

[Chili]

Did either of you use any kind of vibrator or tamper, or do the thing with the reciprocating saw, sans blade against the mold to reduce the air bubbles? Just wondering if you did that and still had voids.

Been thinking about trying a concrete table top..

[Ruffdaddy]

I used an orbital sander but I think 2 main things impacted my results.

1 - I used a regular 5,000 psi blend of concrete and didn't thin it as much as some people do. A countertop concrete blend or specialty mix just flows much better.

2 - my sander didn't put out that much vibration but I had no clue how much was enough.

The best advice I have is to use straight lines as much as possible. The forms I built have a lot of curves and rounds to form fit my patio and cooking equipment. But those curves were a bitch to get right on the form.

[Ruffdaddy]

If you decide to go that route I have 1/3rd of a sheet of melamine left, several feet of wire mesh and a few misc tools you're welcome to. Maybe $40 worth of stuff I'm just going to throw out soon.

[BradM]

Heh, vibrator.

[71chevellejohn]

In a couple of the vids I've watched, the guy sprays a thin face coat into the mold with a drywall texture hopper and lets it set up a little before pouring the full volume in. The tops come out super smooth with that method. I think it is "Modustrial Maker" on youtube that shows how to do it. He's mostly doing it for furniture but it should work for counters also.

He shows it here around the 6 minute mark:
[ame]http://www.youtube.com/watch?v=a3WpKI0YwNY[/ame]


I know this doesn't apply to the OP, but figured it might help others.

[Ruffdaddy]

In a couple of the vids I've watched, the guy sprays a thin face coat into the mold with a drywall texture hopper and lets it set up a little before pouring the full volume in. The tops come out super smooth with that method. I think it is "Modustrial Maker" on youtube that shows how to do it. He's mostly doing it for furniture but it should work for counters also.

He shows it here around the 6 minute mark:

http://www.youtube.com/watch?v=a3WpKI0YwNY

I know this doesn't apply to the OP, but figured it might help others.

Excellent share! I'm going to have to catch up on some of his other videos.

[Chili]

Cool, good info from both of you. I appreciate the offer but this isn't on the short list for me, just something I'm keeping in the back of my mind for now and accumulating information.

[black2002ls]

In a couple of the vids I've watched, the guy sprays a thin face coat into the mold with a drywall texture hopper and lets it set up a little before pouring the full volume in. The tops come out super smooth with that method. I think it is "Modustrial Maker" on youtube that shows how to do it. He's mostly doing it for furniture but it should work for counters also.

He shows it here around the 6 minute mark:

http://www.youtube.com/watch?v=a3WpKI0YwNY

I know this doesn't apply to the OP, but figured it might help others.

You may be able to achieve similar bubble free results by troweling a thi n layer of concrete if you don't want to bother with spraying it in

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