Preparation is everything. Your epoxy or paint should never peel from hot tire pickup, if you prep the floor correctly.
The creation of a Concrete Surface Profile (CSP) is probably the most critical aspect of the preparation process. Epoxy will NOT stick to a smooth surface, it must have something rough to grip onto. The concrete being coated must be turned into a surface similar to that of 80-120 grit sandpaper before being coated, this will insure that the epoxy has something rough to grip onto. When profiling a floor by acid washing, you are also removing the laitance, thus accomplishing the two most important parts of your preparation process at the same time.
Laitance is the thin and brittle layer of concrete resting at the top of all concrete slabs. It is usually only a millimeter or so in depth and is best described as the weak powdery shell or scab at the surface of a slab. This brittle layer of concrete must always be removed prior to any floor coating application. If concrete is coated without the removal of the laitance, the laitance will literally crumble underneath the floor coating when heavy weight is applied. When the laitance crumbles, the epoxy will no longer have anything solid to stick onto, and it will peel.
Acid Washing...
In order to effectively acid wash a slab, you must first degrease and scrub the slab to remove all oil stains. Muriatic acid will have no effect on parts of the concrete sealed with oil, tire stains, or tire shinning products. These areas must be soaked and scrubbed with heavy duty degreasers before being acid washed. It will take approximately 1 gallon of muriatic acid for every 50 sq ft of concrete to effectively loosen concrete laitance and create a profile. This is a lot of acid, so wear safety equipment! You will also need a power washer with at least 3,000 psi. Before acid washing, you must soak your slab thoroughly with water to avoid damaging your slab. Never acid wash a dry slab. Use 5 gallon paint buckets and dilute the acid 50/50 with water. Acid is most effective upon impact, which means that you can not simply throw out the bucket of acid water into the middle of the slab and let is spread everywhere. Acid will only effectively loosen the concrete where it is directly poured. You will need to pour the water directly and slowly over every square foot of concrete. Start in the back of the slab and pour and move in a lawn mower like fashion, moving from left to right, and right to left, across the entire surface of the slab to assure that no spots are missed. You will need several 5 gallon buckets of acid water to complete just a few hundred square feet. When you pour the acid water, it is imparative to have a second or third person with running water standing outside the garage or area being acid washed to diulute the acid water as it comes out of the garage. This will help to avoid staining your driveway with runoff water. You may need to repeat the acid washing process a few times to ensure that all parts of the slab were loosened by the acid water. You do not need to allow the acid water to sit on the floor, it does its work immediately upon impact with the concrete; so when finished, wash off the water thoroughly. Do not allow the acid water to dry on the slab. After washing off the acid water, take multiple 5 gallon buckets with 5-10% ammonia, or one cup of baking soda per five gallon bucket and pour it over every square foot of the floor to neutralize the slab. After the slab has been neutralized you can power wash it. If the power washing does not provide a profile similar to that of 80-120 grit sandpaper then repeat the acid washing process and power wash it again. It usually only takes one or two acid washes and power washes to create a profile. Do not be surprised to see very large amounts (several gallons) of sand being loosened from the surface of the slab, this is the objective. Thoroughly wash off all of the loose sand and allow it to dry for 24 hours prior to coating. Using a squeegee and applying fans can speed up this process. Do not attempt to coat a floor that shows any signs of dampness or moisture, it is better to wait until the slab is completely bone dry before coating it.
More tips on how to epoxy are at HowToEpoxy.org
Hope this helps!
HoustonFloorCoatings.com
