Concrete Acid Stain |Certain Color Changes

RAC Azure Sky Concrete Acid Stain

RAC Azure Sky

Four of our Concrete Resurrection Reactive Acid Chemical Stain colors (RAC) have an asterisk beside them in our catalog and on our website. We often get questions about that, and we’d like to share the answers.




RAC Summer Wheat Concrete Acid Stain

RAC Summer Wheat

Which RAC stains have the asterisk beside the color names?

Olive Mist, Azure Sky, Mossy Oak and Summer Wheat


RAC Mossy Oak Concrete Acid Stain

RAC Mossy Oak


What does the asterisk mean?

It means those four colors are for interior use only because they contain copper atoms. All of the other RAC colors are for indoor or outdoor use.


What happens if I use one of the four marked colors outdoors?

Maybe nothing out of the ordinary. On the other hand, the outdoor concrete may turn a SHADE OF BLACK that may or may not be ugly depending on your point of view. It’s probably NOT what your customer was looking for though, or you either since it’s a permanent condition. Don’t risk it.

RAC Olive Mist Concrete Acid Stain

RAC Olive Mist

What causes the color change?

Oxidization causes the lovely color you started with to turn black. Outdoor slabs usually don’t have a vapor barrier underneath them so moisture from the ground migrates up through the concrete. When the water molecules reach the concrete acid stain, they react with the copper atoms in It and oxidize.

Could this same reaction take place on an interior floor?

Yes, if there is excessive moisture present. Interior floors usually have a vapor barrier though, and that prevents the problem. Always test the concrete with a moisture meter before you take any job regardless of the stain color. Know what you’re dealing with before you begin.

Have more questions about RAC stain? We offer free customer support to those using Concrete Resurrection stains. We don’t, however, answer questions about other brands of stain since we don’t know those products or how they’ll react in any given situation.

You can reach us by email at, use the Live Chat feature on our website, or give us a call at 800-884-2114 where a real person answers the phone.

Using Decorative Concrete Templates Can Be Coloring Book Easy -Tips of the Trade

You’ve ordered your decorative concrete template from Stephen, Template Master at Engrave-A-Crete. It’s delivered quickly and looks exactly like you wanted.

Now you’re faced with a question: What is the quickest and easiest way to mark the engraving lines prior to staining the design elements?

Stephen suggests the following method.

  1. Correctly position the template on the concrete that has been stained with the base color (the light brown portion in the above photo.)
  2. Use gray spray paint (flat) to lightly trace the cut lines. The photo shows examples using gray and black paint. This is for demo purposes only. Gray is much more forgiving on the job site since it resembles the color of the cut lines and decreases the need for extra touch ups with the Wasp.
  3. Remove the template. You now have “coloring book” outlines of the design as shown in the photo.
  4. Apply decorative concrete stain to each segment according to your design plan.
  5. Apply concrete sealer.
  6. Reposition the template using the paint outlines as a guide.
  7. Engrave using KaleidoCrete tools. The spray paint will be removed by the engraving process.

When you need templates or have questions about their use, give Stephen a call at 800-884-2114.

How to Remove Mineral Spots and Keep Your Customer Happy

One of our decorative concrete contractors, we’ll call him Sam, called to ask us about white spots on the driveway he had recently stained and sealed. (see the picture below)  Needless to say, his customer was not happy.

Sam was relieved to find out the problem wasn’t serious and the solution was easy.

So, what caused the problem, and what should you do if you find yourself in Sam’s situation?

According to Chris Mirabal, our Senior Tech Advisor, the problem is generally caused by water droplets from a sprinkler or irrigation system landing on the decorative concrete. As moisture from the droplets evaporates, a mineral deposit is left behind in the form of white spots.mineral deposits on decorative concrete

Is the problem going to rear its ugly head every time it rains?

No, we don’t see the same effect from rainwater since it is “soft” and doesn’t become “hard” until it picks up calcium or magnesium ions as it passes through the soil and bedrock. Groundwater is the culprit.

To fix the problem:

  1.  Mix 1 part white vinegar to 1½ parts water in a pump-up sprayer.
  2. Wet down a workable area with the vinegar/water solution and scrub. (The vinegar solution can kill adjacent grass, so use it carefully.)
  3. Pressure wash.
  4. Blow dry the area with a high-power leaf blower. (Since you’re using “hard” water from the water supply to power wash, it’s important to avoid allowing the wash water to dry, thus create new spots.)

Once you’re finished, take time to talk with your customer about adjusting the sprinkler system so that it doesn’t spray the concrete.  Not only will he avoid the problem of mineral deposits, he will also reduce his water costs while protecting water as a natural resource by using it more efficiently. That’s a win-win for everybody.

Inside Epoxy and the Butter Knife

The importance of how thick Inside Epoxy should be applied  in the decorative concrete process came up recently.

The concrete surface texture is a factor that you can’t control, but have to work with.

Is the concrete surface porous or tight? A porous surface will need a thicker application of epoxy since the pores will fill with epoxy first.

While the Inside Epoxy specs give a range of coverage for each kit, the condition of the concrete and the amount of epoxy used will affect that range.

The applied, finished epoxy should be the thickness of a butter knife which normally takes two applications, each of which will need to cure for seven days.

Applying too little epoxy can lead to flaws in the surface; too much epoxy is just expensive.

So, the correct amount of epoxy on a finished floor is the thickness of a butter knife.

Note: It’s probably best not to carry around a butter knife to measure the epoxy thickness of your customers flooring… they’ll look at you funny and may not give you referrals.  Simply use this knowledge as a guide.

Why You Should Never Put Tape on Concrete

At a building project, concrete is on the scene early, if not first, and endures a lot of rough treatment from the finishing that follows. Since you are responsible for the concrete that will be stained and engraved, your first thought is to protect it from gouges, paint, oils, and more.

Maybe you’re thinking you should tape down a protective cover of some sort?

Don’t use tape!

Using tape on concrete that is stained or will be stained is an absolute no-no. Don’t use it for masking purposes or anything else. Why not?

The glue that makes tape stick will react with new, unstained concrete, changing the color and texture. The concrete will then ‘take’ the stain differently in the places where the tape was stuck down and the places where there was no tape. Getting a good stain color match is going to be hard.

Tape is nasty on stained and sealed concrete because too often, when the tape is removed, it pulls sealer off and can pull some of the stain as well.

It’s not fair to tell you about the problems tape can cause without giving you different solutions to protect your concrete.

The first way to protect new concrete is to let it cure for 30 days before doing any other building procedures. Then, wait until the framing is up.

Spread a 10 mil plastic sheet out on the floor and roll the edges, like a hem.

Now, you can tape…put duct tape on the rolled edge of the plastic to make it sturdy enough to hold staples. Then, staple the plastic to the base plate of the framing, putting the staples through the rolled, taped edge of the plastic.

Last, place cardboard down on the plastic sheet. The cardboard will protect the plastic from sharp tools and help to keep workers from slipping on the plastic sheeting.

Remember that you can contact our senior tech adviser, Chris with questions about decorative concrete engraving at 1-800-884-2114 or email him at