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CHENG Concrete—your
complete resource for creating
concrete countertops.

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Q1: |
What's the difference between NeoMix Original Products and CHENG Pro-Formula?
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NeoMix Original Products refers to three separate components in our original mix
system: Admixture, Water Reducer (liquid form) and Pigment. Each component is packaged
separately and requires you to add them individually to a mixer. When combined with six
60-pound bags
of premium sacked concrete, the mixture yields a three cubic foot
concrete countertop mix.
CHENG Pro-Formula is our latest innovation and engineered for convenient use. CHENG Pro-Formula is an easy-to-use formulation of admixture, water reducer, pigments and
other key ingredients combined in pre-measured quantities and proportions, which yield
an ideal consistency for pouring and finishing (available in 1 or 3 cu. foot
concrete countertop mixes).
Generally, results from both products are the same. Most customers and DIYs purchase
Pro-Formula for its simplicity and consistent results. However, some professionals and
those working on pour-in- place countertop projects prefer our NeoMix Original Products
for the ability to control the individual quantities of admixture, water reducer and pigment.
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Q2: |
In addition to the materials calculated
using the Pro-Formula Project Calculator, what other materials will I need? |
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Pro-Formula is designed to be used with either Sakrete 5000 Plus or Equivalent (six 60-pound
bags for each bag of CHENG Pro-Formula (three cubic feet yield). You can find both of
these bagged concrete products at building supply and home improvement stores nationwide. DO NOT USE any air-entrained
bagged mixes (including Quikrete 5000 Pro Finish).
CHENG Pro-Formula comes packaged in pre-measured quantities for 1 and 3 cf yields.
We recommend these products because we think they produce a finer finish and are more
structurally sound than ordinary sacked concrete mixes. Below you'll find a list of
other critical materials and equipment, which can be found either in our Product Catalog
or in most hardware stores or tool rental shops:
- Melamine (for mold-making)
- Rebar/wire mesh reinforcement (for mold-making)
- Large capacity cement mixer (consult rental shop for appropriate size)
- Wheelbarrow
- Professional concrete vibrator
- Variable speed polisher
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Q3: |
I have your Concrete Countertops book and your product, and noticed inconsistencies with your product instructions—which ones should I follow? |
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Although the book is an excellent point of reference, it was written prior to
the development of our concrete countertop product line. As a result, a few of the techniques, products, and instructions
have varied slightly since the book's publication. That said, when confronted with differing instructions,
always follow the ones printed on the product, particularly with sealers. The book is
your best document for understanding the overall process of pouring a concrete countertop, but our
products are your best tools for achieving a usable countertop mix as they incorporate our best and
latest innovations, so be sure to follow their instructions first and foremost.
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Q4: |
Can I use NeoMix Original Products for a pour-in-place countertop? |
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Yes. For more information about pouring a countertop in place, refer to Appendix B, "Pouring a
Countertop in Place", in Concrete Countertops. For more information about adapting NeoMix Original
Products for this technique, please refer to the FAQs section on Pour-in-Place Countertops.
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Q5: |
Can I make the CHENG colors lighter or darker?
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For those of you wanting to achieve colors that are not offered in the CHENG Pro-Formula collection,
we have introduced CHENG Pro-Formula Base. This pigment-free blend is specifically formulated for the
artisan who wishes to create their own custom colors. By combining CHENG Pro-Formula Base with the CHENG
Base Pigments, your potential color choices are endless.
We do not recommend adding pigments or colorants to the already pigmented CHENG Pro-Formula colors,
since many of these custom blends are formulated to maximum pigment loads.
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Q6: |
I just opened my CHENG Pro-Formula—why doesn't it look like the color I ordered? |
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A bag of CHENG Pro-Formula contains many different ingredients, including our blended pigments.
Once you have mixed Pro-Formula with water and bagged concrete, it will appear much darker than the final color. Only after
the concrete piece is cured, sealed and waxed will it resemble the color you ordered. |
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Q7: |
How do your powdered Pigments differ from other liquid pigments? |
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Powdered pigments and liquid pigments serve the same function, but each has its own
properties. At Cheng Design, we prefer powdered, blended pigments because of the rich
color saturation, subtle inconsistencies and mottled appearance they produce—which we
believe is more natural looking and similar to natural stone. Liquid pigment produces
coloring in concrete countertops that, in our opinion, appears overly uniform,
monochromatic and artificial-looking. We recommend our Base Pigments which
were custom-designed by Fu-Tung Cheng.
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Q8: |
If I do not use your Pigments, can I mix my own pigments? |
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Of course you're free to use your own pigments or create a custom blend with our CHENG Base Pigments.
Remember, the amount of pigment should never exceed 10% of the total cement content of the mix. If you're using
a sacked or pre-mixed concrete mix, there will be no way of knowing the precise volume of cement
that the package contains, and measuring pigment will be difficult. But, if you are willing to
experiment to achieve the exact color you desire, go for it! Just be prepared to put some time
and energy into doing so. Also keep in mind that the color of your wet mix will be much darker
and more saturated than your fully cured piece.
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Q9: |
What should I know about mold-making?
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Mold-making is an art—and science—unto itself. Molds can be simple or complex, designed for thick or
thin and horizontal or vertical applications, and made from a variety of materials. Molds for precast
projects are made in the reverse and negative of the shape you wish to create. The Concrete Countertops
book and the Concrete Countertops DIY Instructional DVD tell you how to make a level, watertight mold for a surface
that is meant to be finished with a polisher and include detailed mold-making tips, such as creating
sink knockouts and incorporating divisions into longer pieces.
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Q10: |
How thin or thick can I cast my countertop?
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At Cheng Design, we prefer thicker (from 2" to 3" thick depending on the project) rather than thinner
tops, as we like the sense of mass a thicker top provides. Thicker tops also allow you to include a bailing
wire and rebar support system within the piece.
The challenge of a thin countertop is ensuring the reinforcement material lies flat within such a
narrow space such that it isn't so close to the countertop surface that it creates a "ghosting"
effect (a slight discoloration in the surface of the concrete along the lines of the wire or rebar).
When casting a thin countertop, or other thin pieces like back splashes and toe kicks (which you can
think of as casting concrete "tiles"), we use wire screen for structural support. For thin pieces, make
them in a moderate dimension (not too long and narrow as they can crack and break very easily), and use
additional care when handling and installing them.
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Q11: |
Do your concrete countertops have integral sinks?
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Yes, we have, on occasion created integral sinks, as have many other fabricators (see our
Concrete Countertops book for examples). One reservation to this technique is that constant
water flow from the faucet to the concrete surface of the sink will eventually erode the top
"cream" layer in that spot, leaving a permanent blemish that will only get deeper over time.
Another, is that in a kitchen application, the wear and tear from everyday use (washing heavy
pots and pans, pouring wine or acidic juices in the sink, etc.) can significantly impact the
finish and overall appearance of the sink area (which is why we favor stainless-steel sinks
in kitchen applications. That said, nothing beats a cast, integral sink for looks—it's the
long-term wear and tear of the sink that is affected.
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Q12: |
What are decorative inserts?
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Inside standard bagged concrete (like Quikrete 5000) is natural stone aggregate. When you polish
the surface of your countertop, you are removing the "cream" layer to reveal these stones,
which can vary throughout the country as bagged concrete is regionally produced. Some people
trying to achieve the "ground" look are happy with revealing the aggregates that come with the
bagged concrete. While others, trying to achieve a truly unique or custom look, will
supplement natural aggregate with decorative aggregate (see Decorative Inserts in the Product Catalog) and place them into
their mold. This addition is an aesthetic decision and has no impact on the structural integrity or
durability of your countertop. For more information on polishing and grinding, refer to
"Grinding and Polishing", pages 136-142, in Concrete Countertops.
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Q13: |
What decorative inserts do you recommend for each CHENG color?
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There is no right answer when it comes to choosing decorative aggregates (see Decorative Inserts). Because this process is completely
optional and based on personal aesthetics and preference, feel free to choose the insert or combination
of inserts that you desire. Whether you are striving for a subtle monochromatic look, or a standout
terrazzo-like finish, you are only limited by your imagination, so have fun! To see Cheng Design's
recommended color and decorative insert combinations Click Here.
View Cheng-recommended Color-Aggregate Combinations »
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Q14: |
If I am not polishing, do I still need decorative inserts?
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If you are not polishing, you are leaving the creamy, aggregate-free layer alone and intact,
and finishing with only light polishing. Since you are not polishing to reveal any aggregates,
decorative inserts would not be revealed from beneath the surface; therefore, they are not
needed with this type of finish.
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Q15: |
How do I achieve a "terrazzo-look" with my concrete countertop?
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Terrazzo is an age-old technique of casting bits of stone into another substance and then
polishing the hardened surface away to expose the added material. You can add broken glass
to the entire mix as though it were another aggregate, or simply scatter glass into the
mold and then pour over it. When using the latter technique, add at least 50% more glass
than you want to have showing in your finished piece, as much of it will migrate away
from the bottom of the mold when pouring and vibrating the mix.
To get around this, we sometimes add a little water-soluble white glue to the glass
before scattering it onto the bottom of the mold or, alternatively, use a spray adhesive
on the bottom of the mold. Once the glue sets, the glass will be stuck to the bottom of
the mold and won't migrate during the pour. Be mindful to use as little as possible and
still get "tack."
We offer a variety of decorative aggregates—bits of semi-precious stone,
moonstone, or tumbled glass—which can be cast into the countertop and then
exposed by polishing the surface once it's fully cured, or hardened (see Decorative Inserts). You can polish your countertop a little or a lot,
depending on how much of the aggregate you'd like to expose and the aesthetic
you're trying to achieve. For more information, refer to "Grinding and Polishing,"
pages 136-142, in Concrete Countertops.
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Q16: |
How do I divide a large piece into sections? Also, how do you get a bullnose edge without pouring right-side-up?
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In Chapter 2, "Building the Mold," of Concrete Countertops, Fu-Tung explains the simple technique of using an
aluminum divide. A more sophisticated approach is to shape the metal divide into a "Z" shape that acts as
a "key" between the two sections. Another option is to affix a half-dowel on the metal divide to act as the key.
There are many ways to make bullnose edges, none of which are very easy. We have made them by building up a
plaster edge with a shaped edging tool (made from sheet metal), then smoothing and coating the plaster with
shellac. We have also heat-formed plastic Mylar, laminate and foam edges as well. This and other advanced
mold-making techniques are covered in our Advanced Concrete Countertop Design Training.
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Q17: |
Is it possible to build a form around existing countertops and pour concrete directly over this surface?
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Generally not recommended. Depends on the condition of the existing countertop.
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Q18: |
Why should I use Quikrete or PakMix 5000?
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Quikrete 5000 and PakMix Super 5000 are sacked concrete mixes or "concrete composite
products" that are pre-packaged mixes of the individual ingredients that make up
concrete (including graded sands, aggregates, and cementitious material).
Both these mixes are rated to withstand pressures of up to 5000 pounds per square
inch (PSI) when fully cured, resulting in a denser, harder, and more durable surface.
Not all sacked concrete mixes rated at 5000 PSI are appropriate for use with our
countertop products. Never use an air-entrained
bagged mix (including Quikrete 5000 Pro Finish), since the results will vary and the
concrete may foam during vibration.
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Q19: |
Can I use ordinary pre-mixed, bagged concrete?
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We don't recommend using ordinary pre-mixed concrete bags because the material is
usually of uneven quality. We recommend higher quality premixed sacked concrete
such as Sakrete 5000 Plus or Equivalent, especially in conjunction with our
Pro-Formula products. Remember, not all sacked concrete mixes rated at 5000 PSI are appropriate for use with our
countertop products. Never use an air-entrained
bagged mix (including Quikrete 5000 Pro Finish), since the results will vary and the
concrete may foam during vibration.
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Q20: |
Can I use white portland cement?
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If you use white portland cement, the color of your countertop will be much lighter when
fully cured than our CHENG color samples (as shown on our website). If you want to use
white portland cement, we recommend you read Chapter 3, "Mix Design", in
Concrete Countertops for a more detailed discussion.
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Q21: |
Will the micro reinforcement fibers show in my finished countertop?
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The micro reinforcement fibers are designed to seamlessly disappear into and bond with
your concrete mixture. If they do accidentally appear, they can be easily burned off
using a light torch or flame.
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Q22: |
How much work time do I have with the concrete mix while pouring?
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Our CHENG Pro-Formula mix achieves its remarkable 85% strength in just four days because of an
accelerant agent in our specially-formulated admixture. As a result, the work time with Pro-Formula
may be less than that of normal concrete. From mixing to pouring to screeding, you have
approximately 30 minutes of work time. Therefore, plan ahead and have your mold, mixer,
water and tools all in place prior to mixing the concrete. You should have plenty of
time to complete your project, but be prepared with your materials and tools and work
briskly.
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Q23: |
How do I know when I've achieved the right concrete mix consistency?
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Like bread-making, you'll know you've achieved the right mix when it looks and feels right. Pick
up a handful of the mix and pour it back and forth from hand to hand to see how it behaves—a
proper mix consistency looks and feels like soft or runny oatmeal. For more information, refer
to Chapter 3, "Mix Design", in Concrete Countertops.
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Q24: |
How do I get a streaked or swirled finish? Can you add pigment to the mix and stir it completely, like making a marbled cake?
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To create a streaked or swirled finish, place concentrated patches of colored concrete
onto the mold and let them stiffen a bit before adding the bulk of the mix. Carefully
vibrate to keep the batches separate from one another.
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Q25: |
I just poured my countertop and it doesn't look like the exact color I ordered—why?
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A freshly poured countertop is not necessarily indicative of the final countertop color. Remember that:
- final actual color will not be known until the countertop is fully cured, approximately 28 days later;
- you are looking at the underside of a countertop which has not been/will not be finished so is generally lighter in color;
- the countertop will continue to evolve and generally darken as you seal and wax it;
- due to the nature of the bagged concrete mix, coloring concrete is an imperfect science whereupon
there are never any guarantees in terms of matching an exact color. To help ensure consistent color on
a project with multiple pours: a) buy all concrete at the same time, and b) pour on the same day.
When working with concrete, be open to and prepared for a product in the color range that you intended, but not
necessarily exactly like the one that you ordered. The uncertainty of each pour (factors include climate and weather
conditions) and the unique characteristics of each product are some of the dynamic and exciting aspects of working with
concrete. Also remember that if you are polishing, bagged concrete is regionally produced so the type and color of aggregates
will vary from region to region as well. Variations in color may also occur due to local conditions including water quality.
If such conditions or variables are applicable to you, we suggest doing a sample pour using a 1cu. ft. container of Pro-Formula
in the color of your choice.
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Q26: |
How long do I wait before I can de-mold my countertop?
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After pouring a countertop, you can de-mold it after four days, at which point the countertop
is at 85% of full strength (approximately 4250 PSI). For more information, refer to Chapter
5, "Curing, Finishing, and Troubleshooting", in Concrete Countertops.
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Q27: |
How long do I wait before my countertop is fully cured?
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Technically speaking, a countertop continues to cure for years after it is
poured. However, after 28 days a countertop will achieve its full strength of
5000 PSI, which is when we considered it fully cured for all intents and purposes.
For more information, refer to Chapter 5, "Curing, Finishing, and
Troubleshooting", in Concrete Countertops.
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Q28: |
How can I prevent cracks in my concrete countertop?
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Good mix design and proper curing are the keys to prevention. Our countertop products are designed to
minimize cracking. Our NeoMix Admixture has micro-reinforcement fibers that help to contain
cracking, and our NeoMix Water Reducer helps lessen the amount of water needed in your
concrete mix while maintaining its workability—another way to help prevent cracks.
The fibers and water reducing agents are inclusive in CHENG Pro-Formula.
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Q29: |
I've heard about countertops curling during the drying process. What can I do to prevent this?
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Countertops tend to curl when they are too shallow in thickness and too much water is
present in the mix. Secondly, curling also occurs when a countertop cures quicker than
it should. To prevent this, "tent" the freshly poured concrete with painter's plastic, or
drop cloths, to keep the curing environment consistently humidified. This paces the cure
time and balances out the natural heat released from the concrete during the process.
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Q30: |
Do I have to grind and polish my concrete countertop?
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Not necessarily. If you like the results straight out the mold, then you don't need
to polish at all. Decide what countertop surface suits your project, your aesthetic.
Generally speaking, any time spent finishing your countertop surface will create a
more sophisticated piece, unless you are trying to achieve that rustic look. If
you are trying to show aggregates and decorative inserts, polishing and
polishing will be necessary.
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Q31: |
How do I achieve a highly-polished look?
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You can achieve a high polish by carefully polishing with the Diamond
Polishing Pads (50, 100, 200, 400, 800, and 1500 grit). First use the 50-grit pad, then
the 100, 200, 400, 800, and 1500, just as marble and granite fabricators do. The
50-grit pad is the most aggressive and should be used to achieve the desired
exposure of aggregate. The 100 to 1500 grits, in conjunction with our CHENG
Sealer and CHENG Wax, will polish the surface out to a high sheen.
For more information, refer to "Grinding and Polishing," pages 136-142, in
Concrete Countertops.
If you are a concrete professional and interested in learning how to achieve our
proprietary mirror-like Geocrete™ finish, you can learn that trade secret and
many other advanced techniques at our Advanced Countertop Design Training.
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Q32: |
When do I grind and polish?
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You can grind immediately upon de-molding, and it's easiest to do so at that point before
the countertop hardens any further. Polishing, on the other hand, (800 grit and above)
should wait until the piece is at least 10 days old, but no more than 28 days. Concrete
that is cured less than 10 days is still too soft to polish; concrete over a month old
is very hard, and polishing at this point will require a lot more effort and a lot of
diamond pads! For more information on grinding and polishing, refer to "Grinding and
Polishing," pages 136-142, in Concrete Countertops.
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Q33: |
Why do I need hand-finishing pads?
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When you de-mold a countertop—no matter how well-done the mold is—burrs and rough spots
will appear on the edges and corners of your countertop. Because it would be too severe
and uncontrollable to hone these spots with a polisher, a Hand-Held Diamond Polishing Pad
is the best tool to hit these spots. Similarly, the edge of a sink knockout or other
detailing that are curved or delicate will require a similar approach when sanding.
Also for touching up and taking out deep stains, refer to "Grinding and Polishing,"
pages 136-142, in Concrete Countertops.
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Q34: |
What kind of grinder/polisher do I need?
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Because of the need to polish at different speeds, the most important feature of a polisher to
rent/purchase is the ability to polish at variable speeds. The polisher should be able to operate
between 800-3000 RPMs. Additionally, since water is required to polish, finding a polisher with a
built-in water feed is the most convenient. The presence of water during polishing also
necessitates a polisher with a double-insulated motor and a ground fault interrupter as
a safety precaution.
Lastly, if you are interested in using our Polishing Pads, make sure that your polisher has
a 5/8" arbor (most standard polishers do) in order to fit our Polishing Pad Holder. The variable
speed wet polisher used in our shop is available in the Equipment Section of our
Online Store. For more information on polishing, refer to "Grinding and
Polishing," pages 136-142, in Concrete Countertops.
NOTE: Be aware of metal-angle grinders that grind at high speeds that look the same as the polishers
we use. These polishers can damage the pad holder or cause excessive wear to your diamond pads.
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Q35: |
Do I need every grit of polishing pad for my project?
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Polishing a concrete countertop is very similar in principle to sanding wood. Starting with the lowest
grit polishing pad, and working your way up through each subsequent grit, ensures that swirl/sanding
marks are left to a minimum. Therefore, when exposing aggregate, we recommend the following polishing
pad sequence: 50, 100, 200, 400, slurry, 400, 800, and then 1500. When not exposing aggregates,
we recommend: 800, slurry, 800, and 1500. For more information on grinding and polishing, refer
to the "Grinding and Polishing," pages 136-142, in Concrete Countertops. For more information on
slurry, refer to "Voids and other Woes", pages 152-157, in Concrete Countertops.
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Q36: |
At what speed do I use each grit of polishing pad?
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Each polishing pad grit requires a different polishing speed because a concrete countertop
can be "over-ground," leaving excessive swirl marks if the polishing speeds are too high.
Generally speaking, the lower the grit, the lower the polishing speed; the higher the
grit, the higher the polishing speed.
We recommend 800 RPMs for 50 grit, 1000 RPMs for 100 grit, 1500 RPMs for 200 grit, 2000
RPMs for 400 grit, 2500 RPMs for 800 grit and 3000 RPMs for 1500 grit. For more
information on grinding and polishing, refer to "Grinding and Polishing", pages
136-142, in Concrete Countertops.
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Q37: |
My countertops have a few small voids (created by trapped air). What is the best way to fill them?
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Voids are best filled with a slurry coat, made of pure cement with either very fine sand or
no sand at all, such as our CHENG Slurry. For more information, refer to "Voids and
other woes", pages 152-157, in Concrete Countertops.
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Q38: |
When do I apply the slurry?
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If necessary, a slurry coat is applied to the countertop after de-molding. We recommend at
least 4 days of curing in the mold if you are using our NeoMix system. Prior to slurrying,
the countertop should be polished, at least minimally, to expose all potential voids prior
to filling. If you are polishing your countertop (exposing aggregate), work your way up
starting from 50 grit through 400 grit diamond pads before applying slurry.
If you are only polishing your countertop (not exposing aggregate), lightly polish your
countertop with an 800 grit diamond pad before applying slurry. For more information on
polishing and grinding, refer to "Grinding and Polishing", pages 136-142,
in Concrete Countertops. For more information on slurry, refer to "Voids and
other woes", pages 152-157, in Concrete Countertops.
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Q39: |
How long do I wait before I continue polishing after slurrying?
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After applying a slurry coat, wait a minimum of 2 days (allowing the slurry a
longer time to "set" is best) before re-polishing. Remember to begin re-polishing
with the same grit diamond pad that was used prior to slurrying before moving on
to the next higher grit pad. Note that because of the size of the holes and the
viscosity of the slurry mix, multiple applications of the slurry may be required
to cover all voids.
* CHENG Acrylic Slurry will "set" faster, allowing you to re-polish after only 12 hours (OVERNIGHT).
Follow the same steps as outlined until all voids are filled in as desired. For more
information on grinding and polishing, refer to "Grinding and Polishing", pages
136-142, in Concrete Countertops. For more information on slurry, refer to "Voids
and other woes", pages 152-157, in Concrete Countertops.
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Q40: |
I just opened my CHENG Slurry—why doesn't it look like my countertop color?
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The contents of a CHENG Slurry may not look like the color of the countertop at
first. Because we use powdered pigments that are all blends (i.e. blue plus yellow make
green), the contents of the slurry kit may appear to be very different until water is
added. When the contents of the CHENG Slurry are mixed with water, the proper
color will be achieved.
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Q41: |
How do I achieve the "veined" look in my countertop?
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Although not a Cheng Design signature, some fabricators deliberately create voids in their
finished concrete, which they then fill with a slurry coat of a different color from the
original piece, to create the "veined," multi-colored surface finish. To achieve this
look, your mold should be hand-packed with a stiffer concrete mix and only vibrated at
a moderate speed. This will produce fairly substantial voids that can then be filled
and finished with one or more contrasting colored slurry coats.
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Q42: |
How is concrete sealed?
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Refer to "Sealing the Concrete" on pages 143-147 of Concrete Countertops. Note,
however, that while the book states that we use penetrating sealers (and at the
time of its printing we were), we now use a "hybrid" topical sealer that also
has penetrating qualities. Our CHENG Sealer is the sealer we actually use in
our shop and is the best all around sealer for use with the
concrete countertops we produce and for the products we sell for others to
create concrete countertops.
CHENG Sealer is a professional-grade sealer created from the latest
water-based acrylic micro-emulsion technology which creates non-yellowing
barrier coat to seal, protect and beautify concrete (thus, it is "topical"
but is not a wet-look sealer). Particularly on porous substrates (like
ground concrete), the sealer will deeply penetrate and provide years of
protective service for your countertop. Our CHENG Sealer is intended to be used in
conjunction with our CHENG Concrete Countertop Wax for additional protection.
Always follow the directions of the actual product you are using.
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Q43: |
When do I apply the CHENG Sealer?
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Once the countertops have been unformed you should allow them to sit 48 hours before polishing.
After polishing is complete you can go right ahead and start sealing using the CHENG Sealer.
For more detailed instructions, follow the directions below,
not those written in the book, which refer to a
sealer we no longer use.
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Q44: |
How do I apply the CHENG Sealer? How long do I wait between coats?
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Here are the instructions for using our new CHENG Sealer:
- In order to achieve a smooth, streak free-finish, take a sponge or clean cloth, saturate the entire concrete surface with clean water, and allow the water to penetrate for 2-3 minutes
- In a small container, mix equal parts of clean water and sealer. This will create a 50% dilution, which we refer to as "wash".
- Using the damp sponge or rag, saturate the countertop with the "wash", ensuring that the entire surface is covered and stays wet for 5 minutes. It is important at this stage to not allow any area of the surface
to dry out.
- Over the next 5-10 minutes, continue saturating the concrete with the wash, as you gradually add more and more sealer to the wash, which increases the ratio of sealer to water.
- For the final wash, wring out the rag, and pour full-strength, undiluted sealer directly onto the rag. Apply it to the concrete surface and let stand for a minute or two.
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Wipe up the countertop surface using the same damp rag, and
be careful to avoid heavy streaks or puddling in the process. Don't allow excess sealer to pool or puddle while drying.
- Apply a second coat (starting from Step 2 mentioned above) 30 minutes after you have completed the first "wash." For best results wait 48 hours before waxing with the newly
reformulated CHENG Concrete Countertop Wax.
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Q45: |
How do I remove sealer from my countertop?
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If the sealer is grossly misapplied, applied considerably too thick, or needs to be removed in
order to refinish the countertop, you may use a Sealer and Adhesive Remover (such as Jasco brand)
to remove all remnants of the sealer from the countertop. In cases of slight excess build-up
or swirl marks, you may want to try burnishing the sealer (before stripping the sealer
completely) with the CHENG Burnishing Pads (available soon!) to see if this alleviates the problem, then
reapply sealer in light coats as directed. For more information about refinishing a
countertop, refer to Appendix 4, "Maintaining a Concrete Countertop", pages
190-193, in Concrete Countertops.
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Q46: |
When and how do I apply the CHENG Wax?
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For best results, the CHENG Sealer should have a full 48 hour cure before waxing.
CHENG Wax is best applied with a moistened wax applicator.
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Q47: |
How many coats of wax do I apply? How long do I wait between coats?
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For a brand-new countertop, we recommend two coats of wax in total. One coat of wax should be
applied prior to installation, and the other coat after installation, to remove any marks and
scuffs resulting from installation. Thereafter, one coat applied once a month is recommended
for continued maintenance.
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Q48: |
Why do you use a carnuba wax as opposed to beeswax?
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Our experience with beeswax is that is less workable and does not create the durable finish of Carnauba. It is very difficult to apply an even consistent coat of beeswax, in contrast to our carnuba-based CHENG Wax, which is much easier to work with and specially formulate for countertops.
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Q49: |
Where can I find local installers and professional contractors?
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Visit our Find a Contractor listing to find a local professional near you that specifically
utilizes our countertop products. You may also visit other online resources that list concrete
contractors throughout the country to find an installer.
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Q50: |
Do I need to reinforce the supporting cabinetry in order to accommodate
the weight of a concrete countertop?
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Your countertop will weigh approximately 135 pounds per cubic foot. Generally
speaking, you don't need to reinforce your cabinetry or floor to support the
top. However, if the supporting cabinets are single-wall or made of particle
board, vertical plywood reinforcements may be necessary. For more information,
refer to "Preparing the Cabinets", pages 159-162, in Concrete Countertops.
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Q51: |
How do I install my concrete countertop?
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A full set of installation instructions (including handling, cabinetry support,
cantilevers, installation of more than one module, dry fitting, final fitting,
and sink mounting) is provided in Chapter 6, "Installing the Countertop",
in Concrete Countertops.
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Q52: |
How do you seal sections of a countertop?
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We seal joints between our modules with clear silicone. We also recommend keying
the joints to allow for a level fit between modules. For more information on casting
in modules, refer to Chapter 2, "Building the Mold," in Concrete Countertops.
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Q53: |
How do I clean concrete countertops?
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Washing your countertop with mild soap and water is the best method of cleaning. Be
wary of cleansers and abrasive pads as they may have solvents and abrasives that can
harm, scratch, or etch the surface of your countertop. Ultimately, prevention is
the best defense—be sure to wipe up any potentially acidic liquids like wine,
vinegar and other substances like lemon or tomato juice immediately.
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Q54: |
What sort of routine maintenance is required to keep a nice finish on
my concrete countertop? How often do I re-apply the finishing wax?
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Ideally, for maximum protection and beauty, we recommend that wax be reapplied every month.
With each coat of wax, your countertop will develop a naturally hard, protective coating
to help repel against staining as well as remove fingerprints and add a lustrous sheen.
Realistically, many owners only wax their countertops once a year or less, and then some
never do at all. Without upkeep and maintenance, your countertop will patina
and stain but this is only cosmetic and will not affect the durability of your countertop. As
long as you like the aesthetics of your countertop, the countertop itself can be
virtually maintenance-free and provide many years of enjoyment.
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Q55: |
When should I apply the CHENG Polish?
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If you are planning to wax your countertop, you can apply the CHENG Polish
after applying the CHENG Wax. Ideally, we recommend that you apply the CHENG Polish once a week to ensure maximum stain protection.
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Q56: |
My concrete countertop was poured with/has developed cracks—can these be repaired?
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If 1/16" or larger of a crack, use two parts epoxy (we recommend PC-7 epoxy)
with pigment and fill the crack. Seal and then wax.
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Q57: |
Can your countertop products be used for pour-in-place projects?
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Our NeoMix Original Products can be adapted very easily for pour-in-place
projects. These projects are challenging because concrete can set very quickly,
making it difficult to pour a large area and trowel the entire surface before the
concrete hardens. With our NeoMix Original System Products, you can increase your
work time by reducing the amount of admixture that you mix in. Whereas our CHENG Pro-Formula admixture has a work time of approximately 25 minutes, reducing the
powdered portion of our NeoMix Original Admixture by half will gain you up to an
additional 90 minutes of work time.
You cannot however eliminate the admixture completely as it contains key
ingredients necessary to strengthen your mix (you want to keep and use all
the micro-reinforcement fibers that come in the admixture). If you reduce
the admixture, please remember to allow for a longer curing time (2-3
additional days) prior to de-molding and grinding/polishing.
Another important note is that most pour-in-place countertops will not have
decorative aggregates as most people leave the troweled finish untouched. If
you are planning on polishing, you can try to sprinkle decorative aggregates
(see Decorative Inserts) on the surface of the countertop during troweling
for a more unique finish.
The mix is more difficult to trowel than ordinary mixes—much "stickier."
Try a small area first to see if you are comfortable with its workability
before committing to a large countertop project.
For more information about the pour-in-place technique, refer to Appendix
B, "Pouring a Countertop in Place", in Concrete Countertops.
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Q58: |
Why do you focus more on the precast concrete countertop technique vs. the pour-in-place technique?
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Cheng Design does not specialize in pour-in-place countertops because we prefer the
benefits of precast, or cast-in-mold, countertops. Nevertheless, we realize that in
certain applications and situations the pour-in-place technique is a viable solution
for some professionals or DIYs.
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Q59: |
Can I pour-in-place for a hand-troweled finish?
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We prefer pouring our countertops into a mold for better control of the surface, absolute
flatness, and therefore less need for labor-intensive polishing. Hand-troweling the surface
of a poured-in-place mold is an art unto itself. Troweling causes the concrete to settle
differently than it would if left alone.
Specifically, troweling can bring the micro-reinforcement fibers (also known as "stealth"
fibers because they are meant to lie beneath the surface) to the top of the countertop
becoming visible, whereby requiring them to then be picked out or burned off. For more
information on hand-troweling, refer to Appendix 3, "Pouring A Countertop In
Place", in Concrete Countertops.
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Q60: |
What is the best way to achieve a smooth finish on a poured-in-place countertop?
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Screed the piece with absolute precision, and have an expert trowel the surface. Timing
and feel are critical in getting a flat, smooth finish. If you're planning on lightly
polishing and grinding the concrete after it has cured sufficiently (4 days or
more, depending on your mix design and cure time), you'll want the flattest surface
possible to avoid extra polishing work.
Ultimately, however, a troweled finish will never be as even, smooth, and glossy as a
precast countertop. For more information about pouring a countertop in place, refer
to Appendix B, "Pouring a Countertop in Place", in Concrete Countertops.
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