Etching is the first preparation needed before painting a concrete surface to achieve the optimum results. The process includes preparing the surface using an acid such that it will react with the particular surface to make it rough so that the paint sticks well when applied.
It is necessary to etch concrete floor before painting because it gets roughed up so when you apply epoxy, and after it has been dried and cured, it will not peel above the floor. There’s multiple ways to actually etch the concrete including sanding, using of acids such as muriatic acid which is widely used and the most common method used by homeowners.
If you are a DIY person and would love to etch your garage, patios or even driveways, a simple method to do this is by using acid. This is far the simplest and the most popular method. Other ways include sanding, which tend to be expensive and can be done by professionals. But nevertheless, the same thing will be achieved.
Why is Etching Necessary?
The main reason why it is recommended not to skip the etching process is for the sole purpose of achieving a long lasting paint on your floor. Etching not only creates a rough surface on the floor, but it also neutralizes the pH level of the surface.
Take an example of why epoxy fails. One of the reasons why they fail is when the etching step is skipped. It can end up not so good looking and will crack and peeled making it even costlier to repair. You don’t need to waste any money removing all over again and start the process again.
If you intent to coat a new concrete floor, then it is probably filled with laitance. This is due to the concrete being weak and has not yet achieved higher strength unlike older surface. In this case, etching is necessary because it will prevent disintegration and the disbandment of the coating being applied.
How to Acid Etch a Garage Acid before Applying Epoxy
You want to floor to be acid etched well so it has a good profile and be rough enough for the epoxy to fall in to the concrete. If the floor is too smooth then the epoxy will get a good bite to the concrete and there’s a good chance that a car pulling into the garage can actually lift up and peel up the epoxy if the tires are too hot.
And in order to spray the floor with muriatic acid, use just a regular plastic or just plastic nozzles and just use a RL flow master weed spray, just light insect weed sprayer and just muriatic acid. It typically, should take about a gallon of muriatic acid to do a two-car garage.
Mix the muriatic acid and if the floor is really, really smooth, you can use it 100% not mixed with anything. If the floor is fairly rough a little bit, then the best ratio is 70% muriatic acid and 30% water.
If you have sprayed and it’s still yellow, then it is actually etching the floor. Once the floor is etched, start washing all the muriatic acid up towards the front of the garage. You don’t want to wash it down the driveway. If you wash it down the driveway before it diluted, you could actually etch and discolor the driveway.
Since most garages are brick-paved, take and wash all the muriatic acid up towards the front and then begin rinse and head down the driveway. Take a water hose all set up and ready to do the rinsing. And then once it’s rinsed, you can then start power washing.
It is always advised to etch any concrete before applying paint because not only will it make it long lasting and avoiding cracks and ugly surfaces, it will save ton of cash that would otherwise be used to repair failed surfaces.