This article is designed to teach the beginner the basics of acid staining concrete. It is not designed to give the beginner the impression that after reading you will have a complete understanding of the entire process, or to give an expert the impression that he, or
she will learn something new.
Staining concrete is more of an Art than a Science, an Art that continues to evolve. The more experience in the staining applications one has , the broadening of his, her limitations.
First it is important that the concrete needs to fully cured. If it is a freshly poured slab you will want to cover and protect it from damage and exposure to risk of stains of any kind. You do not want to merely cover with a construction paper. Use plastic, plywood, Masonite, or any other covers that will not interfere with the curing process.
Preparing the surface: You can do this several ways. First it is a good idea to drop water on the surface in several spots, what this will do for you is tell you if a cure or sealer was applied when the concrete was poured or sometime after. If there is cure or sealer on the surface the water will not absorb in but rather will sit or bead on the surface. If the water beads you will want to profile the surface using a concrete grinder by doing a light grind with 100 or 120 metals. Do not use a buffer with a sanding pad, or a shot blaster. Shot blasters will provide a coarser surface than you want and sanding will only pass on the high points and create trowel lines that show after staining nor will you be able to remove all the cures and sealers.
If the concrete is free of sealers you can use a degreaser to clean the surface , several times is a good idea. There are many different brands of degreasers follow the directions on the bottle. Rinse and vacuum up liquid. At this point there are many ways to apply your stains and concrete dyes, I am going to share with you one basic way.
Acid Staining: After degreasing allow the concrete to dry over night. Starting from the back wall from the exit use a garden sprayer applying in a circular motion. It is a good idea to have some help here. Once you have made a pass use a broom to spread the Acid Stain around while
the Acid is still wet, on your return pass over lap the previous pass with the Acid you are spraying now to remove any patterns created by brooming. Do not walk on the wet surface at all or some how get your feet wet, this can cause foot prints. Continue this until you have completed
the process. Once completed allow the Acid to work for several hours or over night. If you would like to add an accent color here or there you can apply that color now and let it sit for a couple hrs the same as the first application.
Upon your return you may notice areas that have dried this is ok. Now you will need to neutralize the surface. You can do this by applying a mixture of water and baking soda. I use the soda you can pick up at Costco in those big Yellow bags. I mix one bag to 3.5 gallons of water , spread with a mop and broom around. Now vacuum up and repeat the process making sure to remove all the residue, allow to dry over a night or two. If you do not remove all the residue the sealer you use next will not bond to the surface properly , so the clean up is very important.
The sealing process: There are a lot of different types of sealers out there that can be used , I am going to suggest to use one that is user friendly. Acrylic Sealer with 25 to 30 percent solids. Apply the first coat with a garden sprayer , First coat should be reduce to about 15 % solids using the proper reducer for your specific product. This will help to penetrate the product in to the surface. Let dry than apply a second coat , even a third coat if you like.
After the sealers have dried it is a good idea to apply a wax as a ware surface. Spray the liquid floor wax on to the surface and spread with a polypropylene mop and let dry. Buff if you like. Your done !
If you followed these directions correctly you should now have a beautiful Acid Stained Floor...