A crack in a concrete floor is typical for both old and new floors alike. There are many ways to repair cracks but when doing an epoxy coating that require multiple coats you need to repair that crack fast. I ran into this issue as I was installing a metallic epoxy floor in our showroom. I had only a limited amount of down time in which to work and needed a fast set epoxy that can be injected into the crack. Lucky for me, I sell just a product and I was able to grab one off of the shelf and a little over an hour later I was applying my first coat of epoxy.
I didn’t have to waste any time worrying about mixing ratios or measuring. I just popped the cap off, put on the mixing nozzle and put it in the gun and started injecting the crack. The material is very thin and has a consistency of water so it easily flows into a tight crack, like a hairline. Jet black in color it is easy to make sure you have the crack filled, however when cured it is concrete gray in color. When I say this is a fast set crack repair, I mean FAST SET! I had the room temperature around 75F and within minutes the epoxy began stiffening and curing. I gave it 1 hour and then sanded the material down with 120 grit and my orbital sander. To be honest, I forgot to check that the epoxy was fully cured and just went to town sanding away but lucky for me the fast set crack repair lived up to its name. It was rock hard and it saved the day! I was able to able get the primer coat of epoxy down less than 2 hours after I began my floor patching which saved me an entire day.