Concrete Countertops

Decorative-concrete.net

http://www.aceconcrete.com/countertops/index.html

Orchard Supply - White Portland Cement

For your project you will need a 5 gallon pail or bucket, a scoop, a weight scale, and a cement mixer. Be certain to read and follow all of the cement manufacturer's warnings on the bag of white portland cement.

We sell 94 lb. bags of Lehigh Type I white portland cement, so these suggestions are for the type of cement we sell, using 3/8-inch pea gravel for an exposed aggregate finish. Weigh the 5 gallon pail or bucket (a plastic bucket usually weighs between 1.8 and 2.1 lbs.). Weigh out 10 lbs. of white portland cement (if, for example, your bucket weighs 2 lbs, then the scale will read 12 lbs.). Pour the cement into your mixer. Weigh out 25 lbs. of 3/8-inch pea gravel. Pour the gravel into your mixer. Weigh out 20 lbs. of sand (what is known as Salton sand is used if you want the concrete to be light colored). Pour the sand into your mixer. Then add 5 lbs. (half the weight of the cement -- water weighs 8.33 lbs. per gallon) of water into the mixer and thoroughly mix. You will get a workable mud pie consistency.

For a stronger, smoother concrete: Weigh the 5 gallon pail or bucket (a plastic bucket usually weighs between 1.8 and 2.1 lbs.). Weigh out 17 lbs. of white portland cement (if your bucket weighs 2 lbs, then the scale will read 19 lbs.). Pour the cement into your mixer. Weigh out 20 lbs. of 3/8-inch gravel. Pour the gravel into your mixer. Weigh out 18 lbs. of sand (what is known as Salton sand is used if you want the concrete to be light colored). Pour the sand into your mixer. Then add 8.33 lbs. or 1 gallon (approximately half the weight of the cement -- water weighs 8.33 lbs. per gallon) of water into the mixer and thoroughly mix.

Fritz-Pak
Concrete Countertop Admixture

COUNTER-FLO

uddy rhodes has some edge molding predone for cast in place.

Buddy Rhodes


I'm sure you could use it for precast. Also you could call a local millwork shop, they could likely make a negative mold for anythign you could think of.

I did another set of 3 test pours same as before; 1 inch thick, 2 inch thick, and 3 inches. Same consistency, 3/4 gal of water with 2 gals (1/2 bag) of Quikrete non-shrink grout mix. I used black colorant this time. I used tan-ish last time. Bubbles rising to the surface are MUCH less of a problem if you don't vibrate the mold/forms. I had read that with non-shrink grout, if you vibrate it, the aggrigate will segragate from the mix. This is what I think is causing all the bubbles. Just pour, screed, and leave it alone. Even so, some small bubbles may still appear. If you're doing pour in place the trick is to wait about 1.5 hours for "thumb print" dry then go over it with a trowel. This wets it up and gets rid of any bubbles on the surface. Of course you will still have allot of sanding to do to get it smooth.

I popped yesterdays pours out of the plastic molds. The bottom surface is amazingly smooth. You could see every detail of the mold - even the tiny numbers I hadn't noticed that were molded into the plastic trays. So far, 36 hours later, there are no visible cracks.

Given this, I think pre-casting countertops upside-down is the thing to do. However, the bottom is so smooth it almost takes on a plastic corian-like appearance. Not as good looking IMO as pictures I have seen of tops made with a modified "standard" concrete mix like Quikrete 5000. But these tops were obviously ground down smooth which requires allot of grinding with diamond wheels, etc.

I may do another test adding pea gravel to the mix, to see if it
gives a better, more natural, look.

I was just looking at Cheng's Neo-mix Pro product. It's about the same cost as using the non-shrink grout. Hmmm...

Tu-Fung Cheng's Concrete Mix

Well first trial commenced tonight.

Mixed up a batch of the Quikrete non-shrink grout tonight
and poured it into some test molds - plastic plant "drain trays"
like you put under plant pots. One is about 3/4-1" deep by
6" in diameter, One is 1.5-2" deep by 14" in diameter,
another is retangular 4x18" by 4"deep to just get
rid of the extra and also see how it dries REAL thick (ya
never know, maybe it has application for fireplaces, etc.)

I used 2 gals (1/2 bag) of mix and 3/4 gal of water
as per direction on bag for a "fluid" mix... very
wet like syrup. (bag says 1 gallon and 3 pints per
50lb bag which is slightly under 4 gallons)
At this consitency it pretty much levels itself, so
no troweling done.

Yes lots of bubbles come to the surface even though
I mixed it by hand with a small rake moving slowly. .
Seems like the thinner (depth not consistency) the pour
the less the bubbles. I'm wondering if
it's mixed dryer if it will keep the bubbles from
floating to the top - maybe next batch.
It's still quite wet 1 hour after starting pouring it.

I mixed into the water 1/2 bottle of orange-ish
Quikrete cement dye/color into the water prior
to adding the grout mix. After pouring into
the molds I could see "veins" of the color so
I guess I didn't mix it long/good enough.
But the effect kinda looks cool and organic/natural
like stone. We'll see what it looks like after it
dries. Right now it looks brownish, nothing like the color
of the orange dye probably because of the dark
grey grout.

2 hours after pour, they have set up quite a bit.
I took a plastic putty knife and went over the top
of thickest mold - as it had quite a few bubbles
and bumps. This wet up the surface and smoothed
it out quite a bit. I imagine if you had some
really big "pits" you could wait a bit longer for
it to fully set up and then use another "peanut butter"
batch and a rubber grout float to fill in the voids.

http://www.concretenetwork.com

Off topic: Slate flooring... http://www.vermontstone.com/pricing.htm

Quikrete sales rep (Dave Ford) said same thing - don't add anything to their non-shrink grout - no telling what will happen. Anyway, he said you don't need it. He said it has the following strengths (when dry) as per consistencies:

Plastic (mashed potatoes/putty?) 14K psi
Flow (pancake batter?)11K psi
Fluid (pancake syrup) 8K psi

He boldly claimed you can just pour the stuff in "fluid" form without working it and without any wire/bar reinforcements and it will be sufficient.

Hard to believe, but great if true.
He also said he met Cheng at a show adn said he uses Quikrete 5000 (perhaps with his own additives?). He couldn't understand why Cheng used it instead of their grout and Cheng said that's just what he has been using for years, so used to it I guess.

You can bet I'm gonna prototype the fluid grout thing - check my blog later to see if it worked :)

Great pictures from Concrete Canvas

fabricators:

Buddy Rhodes: http://www.buddyrhodes.com/ (877) 706-5303

Fu Tung Cheng: http://www.chengdesign.com/ (510) 502-4037

Gerald Santora: http://www.soupcan.com/ (312) 243-6928

Kelly Carr: http://www.concretejungleonline.com/ (301) 495-9010

David Jansen: http://www.sonomastone.com/ (877) 939-9929

For information on cleaning and maintaining a concrete countertop—try the National Training Center for Stone and Masonry trades: http://www.ntc-stone.com/

coating material? --> http://www.epoxy.com/

I spoke with a Quikrete sales rep about the "bubbles" problem.
He said this can happen if you use an electric mixer (paddle) at too high a speed it will put air pockets/bubbles into the mix which can rise and/or coalesce at or near the surface. The solution is to mix slowly and tap edges of bucket to release air.

He knew of several people who had success with their grout. OK, so he's not completely unbiased ;-)

http://www.chengdesign.com/geocrete.html
http://www.graniterock.com/
http://www.glaze-n-seal.com/

Glaze 'N Seal. Wet Look clear lacquer gives decorative concrete a beautiful, durable, and long-lasting finish, according to the firm. It protects all types of decorative overlays and surfaces and is suitable for interior and exterior use. It dries quickly and resists chemicals, abrasion, sunlight, efflorescence, and stains, the company says. A low-VOC version, Wet Look 2000, also is available. 800-486-1414. www.glaze-n-seal.com. Circle 216.

New England Concrete Countertops

Fritzpak Countertop cement admixture

I talked to Fritzpack (Gabriel the president actually) about their CounterFlo "Countertop Admixture" specifically made for countertops.

http://www.fritzpak.com/news/ct_press.html

His recommendation:

1. Supplement 10 lbs of Portland cement for each 80 lbs bag of premixed concrete (he mentioned no brands/types).

2. Use 1 scoop (2 oz.) of CounterFlo per bag of concrete, or for every 20 lbs of cement.

So given recipe above it would be 1.5 scoops (3 oz.) of CounterFlo per batch of above.

CounterFlo is $45 per per 8 lb container. This is 192 ounces, enough for 63 batches of above recipe!

=======================

COUNTER-FLO
Concrete Countertop Admixture
NEW PRODUCT INFORMATION

Counter-Flo, Fritz-Pak's Concrete Countertop Admixture is a mixture of water reducers and mineral admixtures specifically designed for use in the production of concrete countertops and concrete statuary. It makes concrete more flowable for easy placement without adding additional water, allowing you to reduce the water:cement ratio in your mix. By lowering water content you achieve higher compressive and structural strength, thus allowing faster demolding and a faster cure. Lower water content will also provide a denser and less permeable concrete, making the concrete less prone to staining. Use of Counter-Flo allows you to place a relatively wetter concrete, reducing the amount of air bubbles, so concrete will yield a better pattern definition.

Packaging:
Counter-Flo comes in an 8-lb re-closable plastic container. Enclosed is a plastic 2-oz (volumetric) scoop for easy dosage. The container yields about 66 scoops of material: enough to treat 1320 lbs of cementitious materials. MSRP is $45.00 per container.

Directions:
Preferably, Counter-Flo should be added to the dry concrete or mix materials before adding water. Blend thoroughly within the dry materials and proceed mixing the concrete normally, but using about 20% less water. If added to wet concrete, sprinkle over all the concrete to avoid areas of high concentration, then mix well for 5 minutes to allow the active ingredient to hydrate and disperse within the concrete.
For pre-bagged concrete: Use 1 level scoop (2-oz volume) per 80 lb bag of concrete. For higher water reduction you may increase the dosage rate, but do not exceed 3 scoops per bag of concrete.

For site made concrete: Determine the total amount of cement in your mix and add 1 level scoop (2-oz volume) for each 20 lbs (9 kg) of cement.
For modified pre-bagged concrete: Add enough Counter-Flo for the pre-bagged concrete and then add Counter-Flo for the additional cementitious material added. Add one level scoop for each bag of pre-bagged concrete and 1 additional level scoop for every 20 lbs of cementitious materials. Cementitious materials include fly-ash, silica fume, slag or calcined clay; include them as part of the cement weight in order to determine the number of scoops to use.

Notes:
Good Practices. Always follow good concreting practices when using Counter-Flo. We recommend the practices of the American Concrete Institute, (ACI), the American Society of Concrete Contractors (ASCC) or the Portland Cement Association (PCA).
Pigments. If pigments are used in your mix; add Counter-Flo before or at the same time as pigments are added. Counter-Flo will help disperse the pigments within the mix.
Timing and Re-Dosing. Counter-Flo will gradually lose its effect within about 45 minutes of adding water (faster in warm climates >80F). If effects wear off, fresh unplaced concrete may be re-dosed to regain flow properties.

Available Feb 27, 2004, Call 888-746-4116 or your Fritz-Pak Distributor for more information.

video http://www.thestampstore.com/video.htm

Time to Mix the Concrete

The mixing of the concrete will be the most challenging task in making a concrete kitchen countertop. Ryan suggests that you mix your own concrete to create the most sturdy mixture possible

Determine the rough volume of the countertop -- for 1-1/2" layer of concrete use 15 lbs. per square foot. From the inside of the mold, measure the length, width and height and multiply all three to determine the square footage.

Cement recipe:

1 part cement (type 1 or 2)
2 parts rock (3/8-inch pea gravel)
3 parts sand (finest aggregate)
Water, water reducer and pigment (your choice)

Note: If you are going to use pigment, it should be 4 percent of the weight of the cement. Measure carefully.