I am covering my basement apartment's concrete floors with epoxy. The concrete is very well done (self done, been several years, no cracks, reinforced, 2-3" thick).
In order to test the epoxy, I designated my washer/dryer bay as a trial area because it is really the only part of the floor that will be covered, IOW low consequence for messing up. During the extensive conversations with a relatively helpful associate from the epoxy company, I was told that prepping/cleaning concrete is critical to the outcome. There are essentially two (as it turns out, not mutually exclusive) techniques to prepping the substrate: mechanical (grinding with a diamond blade) and chemical (muriatic acid OR a less invasive/hazardous etching solution). I opted for the concrete etch, to avoid the dust of grinding and the toxicity of acid.
So I first scrubbed the concrete really well with a rub brick and then treated it with the etch. The results were good and the removal of concrete cream (the objective of the etch) was successful. That, however, made the substrate rougher as it exposed the concrete gravel parts by removing what was in between. The epoxy company people told me that was a good thing because the epoxy needs roughness to catch on. Essentially, the substrate after the prep had the texture of laminated grains of rice.
The epoxy application, excluding the prep, consists of three layers: water based primer, solids (mid coat, the 'meat' of it all), and urethane top coat for gloss and texture. When I applied the solids in the trial area, using a 3/8" nap roller, the 'laminated grains of rice' texture remained but to a lesser degree. I understand that in a final implementation, a flooring squeegee should be used to accurately distribute a proper amount of epoxy but I didn't have a squeegee so I just used a roller. I do plan to get a squeegee for doing the final job. In order to see the difference between a thicker and thinner layer of the solids epoxy, I then applied a second coat with the roller on just one half of the trial area, so that I have something to compare it to. The results were better (less rough with the 2nd coat) but still not perfect.
When I discussed the results with the epoxy company guy, he said that I was getting such results because I didn't grind the concrete. I told him I was under the impression the whole time that etching was alternative to grinding, which I was trying to avoid by all means.
Is it possible that I was not simply getting the epoxy level above the tips of the tips of gravel particles because the 3/8" roller wasn't applying enough epoxy? Would I be getting thicker coverage if I had used a squeegee?
The product documentation mentions a (nominal) thickeness of 3 mil. Let's say I need a little more than that to "drown" my roughness. What size squeegee notch should I use? (e.g. I think they come in 1/8 and 1/4").
MOST IMPORTANTLY: Is it "drowning" the roughness with more epoxy a feasible strategy to achieve smoothness, IOW a viable alternative to the hellishly messy job of grinding concrete? I don't mind buying more epoxy to avoid grinding.
I did get some answers from the company guy but I am reaching out to get some second opinions.