First, you will want to start off by picking out your main color. This stage can be one of the trickiest aspects of the stamping concrete. You can start off by getting yourself a color swatch, the best way to pick your color from a color swatch is to pick a color from the swatch and then go back one or two colors to get the actual color that you want. This is similar to picking out a color that you want to paint a room. There are many variables such as lighting and the other colors in the room (couch, carpet, room dressings, etc.) that you wish to paint. I am sure you have picked out a color at the local paint store and started to paint your room and suddenly it just doesn't seem to match the color you picked from a swatch. This is what I call perceived vision.
If you can relate to what I have just mentioned it also applies to picking out a color for your stamped concrete project. There are many variables of perceived vision, such as sunlight and surrounding colors, the color of your house, grass, and landscaping. Another way to pick your colors is to visit your local decorative concrete supplier and view some of the samples or photos they may have hanging on their wall. You may ask them or any one else if they know of somewhere there is a stamped concrete project so you can see the actual finished project and see for yourself how it either blends or contrasts with the surrounding landscape.
Onto pouring and finishing your first stamped concrete project. If I may suggest how you should order your concrete. First, you will want to let the concrete company know that you are going to put color in the concrete truck, and whether or not you're going to be using a wheel barrel, they will appreciate this. Your next step is to order a 4000 psi ( pounds per square inch) mix with a rock or 3/8" rock (aggregate), the reason for this, is that larger rocks can pop up through your finished concrete as you start to stamp on the mats. They may try and up sell you on a "stamp" mix but I would not use the "stamp" mix it is full of additives like slag and fly ash, and it will cost more money. Then I would like to stress that you do not want to do a stamped concrete project that is more that 150' sq.ft., since this will be your first time.
After the concrete truck gets to the location of your project, let the driver put the color into the concrete truck for you, and let it mix for at least 10 minutes. You may some streaking of the color as it comes out of the concrete truck, do not worry. You will want some color differences as this will resemble the natural colors of what ever impressions or stamp that you have chosen for your project. For example if you look at a rock you will notice that it has many shades of the same color and often some other colors.
Place the wet concrete inside your form work and leave it about a ½" higher than the top of your forms. A good way to get a rough grade is to use a tool called a concrete rake or a square edged shovel. Once you have gotten the concrete ½" above your form work you can start the "screed" process. You will need a straight 2"x 4" to screed with. You will need someone to help you with this process. Once you have one person on each side of the screed board each of you will start to pull the concrete towards the end of the form work leveling as you go along, the purpose of a screed board is to level out the concrete inside of your forms and to also knock down the aggregate or rocks inside the cement. Basically what you will be doing is to pull the screed board toward you in one foot intervals, curling the screed board as you pull it towards yourself. You can repeat this process as many times as you need until the concrete is flush with your forms. Repeat this process until you have come to the end of your form. Before you get close to the end advise the concrete truck driver that you are almost finished and not to load up the chute, because you will be responsible for its' disposal and a place for him to wash out his chute. I often use a wheel barrel if the is no where else to wash out. Although, you probably want 5 or so shovel full of concrete if you need to add any concrete after you bull float and edge your project. At this point you will need a bull float to close the surface of the concrete. Generally you will run the bull float from top to bottom across the concrete overlapping each previous pass approximately 50% and then repeat the process from side to side. Do not worry about getting it completely flat, as once you begin to stamp it will not be flat at all. Do not get caught up on small dips or small elevation changes in the concrete. Now you may begin to edge the perimeter of the concrete with an edging tool, again do not get caught up on doing this perfect, especially if this is your first time. Now you will run a fresno (pole trowel) across your project in the same manner as the bull float.
Are you ready? Let's start stamping your project. Before the concrete truck gets to your house there are a few things that will help you save time. Time is of the essence when it comes to pouring concrete, it is one of the few products that will not wait for you. First off, you will want to place the liquid release agent into a cheap garden sprayer and also get yourself some surface retardant and do the same. Liquid release simply allows you to place the rubber stamp onto the concrete without pulling off the finish of your concrete; the surface retardant will slow the set time of the concrete if you feel you are getting behind. There is also a another concrete retardant product that you can use by placing the bag of internal concrete retardant into the truck. If you choose to use this retardant, here are some guidelines; pour out your first yard of concrete (an area of 81' sq.ft.) without any internal retardant and then after every yard (81' sq.ft.) put a bag of internal retardant inside the concrete truck. By doing this you will buy yourself about 30 minutes of time per yard, allowing you to get a more fluent looking stamped impression throughout the whole project , rather that having a nice deep impression at the beginning of your stamped project and a not so deep of an impression at the end of your project. Spray the area of concrete that you will be laying your stamp with liquid release. You will want to spray the liquid release somewhat generously, and also spray the stamp itself before you place the stamping mat onto the concrete. You will not want to spay the entire project at once as this will accelerate the setting time of the concrete and the liquid release will dry up before you get to the end of your project, which is a waste of liquid release.
Place your first stamp down and set the next stamp tight against the stamp mat that is already on the concrete, making sure that the handles on your stamps are all running the same direction. If you have help it is best to assign a specific role for each person. What I mean by that is, one person will spray the liquid release, one person shall pick up and place the stamp mats and the other person will actually step on the mat and make sure it has left a good impression. Repeat this process until you reach the end, it's that easy. One other thing you might do while you're stamping is to use a roller tool to flatten out the bead that will form when you place the mats together. You may also do this process with a hand grinder after the concrete sets.
Now let your let your project cure for about 3-5 days depending on the temperature and if the weather has been sunny, rainy or just an overcast of clouds. During those 3-5 days you will want to wet your project at least twice a day, as this will help keep the concrete cool and will help in the prevention of premature cracking and delaminating. After this period it is time to add secondary colors or the antique stage. For this you will need to get an antique agent, I suggest you use charcoal or grey for your first time. You will also need to get some xylene, it is a quick drying solvent, and it requires one gallon for every 80_90 square feet. You will then add 5 tbsp. of antique agent to the xylene in a 1 gallon garden sprayer and stir or shake for about 45 seconds. I use cheap garden sprayers because the xylene will dissolve the rubber gaskets.
In a somewhat circular motion spray the secondary colors onto the stamped concrete project, keeping in mind to spray some areas thicker that others, while being careful not to spray it on to thick, this will give you a more natural looking finish. You may also get come concrete acid stain and apply it randomly on individual stones or slate blocks depending on the stamp impression you have chosen. Another tip is to pour a small square nest to your project, stamp it, and use this to practice applying your secondary colors and acid stain. If you decide to apply acid stain I suggest that you start with ¼ cup of acid stain to 1 cup of water to dilute the stain, you can always increase the tint or darkness of the acid stain by adding more stain to water ratio, but you can not decrease the darkness once it is applied to the surface of the concrete.
Let the xylene dry and apply two coats of; non-yellowing, solvent based acrylic sealant. Your project will be a lot darker when you apply the sealant than you anticipated, not to worry, the sealant also needs to cure. Within a day or two it will lighted up to your perceived vision.
If you have further questions about this process you may visit my web site for further details. I am at www.howtocrete.com
» left by Louie Jerome(4) Louie Jerome (138 days 6 hours ago.)
Lots of information and I found it interesting and useful. Just would have been easier to read if you broke thos long paragraphs up a bit. (Just a suggestion.) Respond to this comment
» left by John Mindrup from Kansas City, MO (138 days 5 hours ago.)
I am so glad you enjoyed the article and found it useful. I will work on those long paragraphs. If you have any questions when you begin your project and do not need the visual aids ( the 5 set DVD collection; stamping, acid staining and concrete engraving-graphic designs and logos) I will be happy to answer them for free. Just post your question here. It is against the rules to leave my e-mail. Good luck on your project.
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