Longmont, CO new WFO build - casted over sand

[cnegrelli]

Stucco has to be worked to get the desired finish. It comes in different blends for the different layers. You may be able to sieve (I use an old window screen) some of the larger aggregate out of what you have to get a smoother finish coat. (add the fiber back to the mix) You may also get a smoother finish by using a coarse damp sponge on the finish coat before it totally sets. The damp sponge will knock down the high spots and fill in the low spots.

The product that I linked is not just a paint. Going up a couple of posts, and referencing the product description, it has most of what David S recommends for the waterproof flexible acrylic coating.

Thanks. I assume you sieve a dry mix. I have the premixed acrylic stucco that is already wet. It is also pre-colored, but if it doesn't come out the way I hope, I suppose I'll be painting it! My stucco is on a cement board enclosure, with a vent so it doesn't get any heat at all (6" of blanket on dome, plus vermiculite up sides covering 70% of dome area).

[Gulf]

......I assume you sieve a dry mix. I have the premixed acrylic stucco that is already wet...............

You are right. I am too old school. I have no experience with all the new products on the market. But, working any stucco will get the surface smother. I hope that it all works out to you satisfaction.

[cnegrelli]

Slow progress due to lots of rainy weather the last few weeks (snow today), but looks clear ahead. I've applied the base coat of cement stucco and I did a test pour of a small counter piece and a keystone brick for my arch facade over the weekend. Used the quikrete counter top mix and melamine forms with good results. Yesterday, I tried a few putting up a few of the ledge stone pieces on the backside of stand (Eldorado's Cascade line that I bought off craigslist cheap). I mixed up my own mortar (still trying to use all that sand I have left over from my dome mold) and attached a few pieces. Will need to figure out how to cut them (time to borrow that wet saw). I also used the extra mortar to coat the storage area under stand. Looks like stucco and a lot better than plain CMUs that were dry stacked.

One question I have is for countertop support of a span. I plan to pour a 2" thick countertop that extends 3.5" beyond existing stand edges. I've read that most use the ladder-wire rather than rebar, but I'm quite certain I will need more strength to span the 4' or so across the front (see pic). With a 2" thick pour could I use angle iron and or rebar here? If not, why?

Essentially, I want one continue pour and thus the front section above stand opening will be 3.5" wide, by 2" tall and supported at either end. Will that work?

[cnegrelli]

Well I decided to use 3/8" rebar along the front cantilever 3.5" wide counter and then used the smaller Ladder Wire thorough out the rest of the cast. Used Sakrete Charcoal colorant for each 80 lb bag of Quikrete COuntertop mix. Used SikaLatex Acrylic Fortifier in place of water. Used a single 1.1 gal bottle per 80 lb of concrete mix. This was easy to work with and seemed like a good mix.

Ended up sprinkling some crushed glass onto the surface at the end and working in a bit. Not sure I did that right and hope I don't regret it. Not sure I got it down far enough as it's definitely mostly exposed.

Picked up a wet polisher on craigslist. Would like to start polishing/grinding near end of week. Too early?

[cnegrelli]

I've read the threads on concrete countertops. I'm getting ready to start polishing and I'm wondering how I might seal (what product). It seems like a good sealer and perhaps Butcher Block Wax may be the ticket, but what's a good sealer?

My counters used Quikrete countertop mix with 100% replacement of the water with Acrylic Fortifier (Sika Concrete bonding agent). Made the mix very workable and I'm happy with how they came out. Thanks to Gulf for that suggestion!

Sealer recommendations please!

[UtahBeehiver]

There are several "food safe" concrete sealers out there, I used one from DirectColors, a lithium base sealer, Cheng makes one as well. Be aware, they are much more spendy than your off the self, none "food safe" concrete sealer, ie 30-35 bucks a quart, but a quart goes a long ways.

[cnegrelli]

There are several "food safe" concrete sealers out there, I used one from DirectColors, a lithium base sealer, Cheng makes one as well. Be aware, they are much more spendy than your off the self, none "food safe" concrete sealer, ie 30-35 bucks a quart, but a quart goes a long ways.

I think I will also go with the DirectColors brand. I noticed it says to Polish to 200-grit. Then apply the Penetrating Lithium Sealer with a pump up fence and deck sprayer.
• Allow to dry for 24 hours and begin polishing from 400-grit up to 3000-grit.

I was thinking this was applied after all the polishing. No?
Did you use this sort of sprayer?

Edit: Did some more reading and I guess that's the way we'll do it. I was going to grind some today (80 degrees) but rain and then a very hard freeze tomorrow (teens), so I think I'll wait on that until the weekend and try to keep the countertops relatively dry thru tomorrows rain. Not sure that it matters.

[UtahBeehiver]

My installation instructions for the sealer did not say to polish after application. I used paint pads vs sprayer and kept area that soak up faster than others saturated. If you want, I have a half a quart left you can have, you just pay for shipping.

[cnegrelli]

Re-reading my instructions on the website, and I'm not sure now where I saw that information about polishing after. Thanks for the offer, my product already shipped and should be more than enough!
Thanks for the tips on Paint pads. I will do same and also have a squeegee handy.

Rain later today and 20 degrees overnight tonight. I'm going to get some plastic down to keep the counters dry. This is a one day deep freeze.

[cnegrelli]

I've gotten a couple passes now on the countertops with wet polishing at 50 grit diamond pads, taking out the trowel marks and some high spots. Plan to get up to 200-400 today and then slurry some of the small holes I have. I have not been able to find the mix recipe (I used up all my countertop mix, so I need a homebrew). I plan to color it darker than countertops. I also have a place to fill in the family name signature my sone did in cursive on the back with a colored slurry as well. Racing against the clock as Denver is now in the season where we can have all kinds of weather. 70 today, and no freezing temps in the 10 day forecast! Big weekend. So any help on the slurry recipe appreciated. Calling UtahBeehiver deejayoh Tscarborough Gulf DavidS as I've read each of your comments on this subject but can't seem to find a recommended recipe!

[UtahBeehiver]

To fill the bug/air holes I just used a slurry of cement,dye and acrylic fortifier. The following is from Cheng's Concrete counter web site:

Slurry is a mixture of cement paste, pigment, and water. It is used to fill in the small air bubbles in the surface of the concrete. This is especially important in something like a concrete countertop, because bacteria can get into those holes and grow. Otherwise it’s an aesthetic preference, some people don’t mind the natural look while others are looking for a more refined surface.

[cnegrelli]

To fill the bug/air holes I just used a slurry of cement,dye and acrylic fortifier. The following is from Cheng's Concrete counter web site:

Slurry is a mixture of cement paste, pigment, and water. It is used to fill in the small air bubbles in the surface of the concrete. This is especially important in something like a concrete countertop, because bacteria can get into those holes and grow. Otherwise it’s an aesthetic preference, some people don’t mind the natural look while others are looking for a more refined surface.

Thanks Russell. That was helpful and it went pretty easy, followed what you did and it seems to have gone pretty well.

I was re-reading the directions this morning of the Colors Direct Lithium sealer I bought, and the directions on the bottle don't really specify when you apply it, but then I did find the app note on the right side of their web page entitled "How-to-Apply-DCI-Penetrating-Lithium-Based-Sealer1" and sure enough, it states:

"Polished Countertop Application (once the countertop has cured): • Polish to 200-grit. Acid Stain if desired and clean before sealing. • Apply the Penetrating Lithium Sealer with a pump up fence and deck sprayer. Spray enough to create/maintain a uniformly damp surface for 20 minutes. Apply more sealer only to areas that appear more dry or absorptive than others. No membrane should be forming on the surface. • Squeegee away any excess sealer remaining on surface. Do not allow sealer to pool anywhere on the concrete. • Allow to dry for 24 hours and begin polishing from 400-grit up to 3000-grit."

So that alters my plan today! I will polish off the slurry, and apply the sealer late today. Then I'm off to SLC for business for a few days and the rest of the polishing will have to wait (but you can certainly cash in that beer I owe you Monday night)! I think having the sealer on there for a good 24 hours before the snow hits us again on Tuesday should help a lot. Would you both to cover the counters given this scenario?

[Gulf]

Have you read anything on the product about it's compatibility with the acrylic? The acrylic fortifier makes the concrete less porous. I'm sure that may also depend on how much water was replaced with the acrylic. The quote calls it Penetrating Lithium Sealer. I'm just wondering how well it will penetrate this type of concrete. I am very interested in how well it turns out. I have some kitchen counters to do and my oven landing could also use a little more polishing while I have everything set up for it..

[cnegrelli]

Have you read anything on the product about it's compatibility with the acrylic? The acrylic fortifier makes the concrete less porous. I'm sure that may also depend on how much water was replaced with the acrylic. The quote calls it Penetrating Lithium Sealer. I'm just wondering how well it will penetrate this type of concrete. I am very interested in how well it turns out. I have some kitchen counters to do and my oven landing could also use a little more polishing while I have everything set up for it..

They do recommend a polyurethane sealer, but I couldn't get anything definitive from them. Since I used 100% acrylic fortifier, my expectation is that little of the sealer penetrated and thus it may be of limited use.

Which begs the question, do I need a sealer? Should I wax it? Should I go with a polyurethane sealer that is more of a covering membrane, than a penetrator? All discussion on this welcome! Winter is closing!

The Colors Direct sight support folks state it depends on the look I'm after. I'm after protection from freeze/thaw!

[cnegrelli]

What have people found that works best for sealing between the stucco and concrete countertops?