If you have a helper when you pour your hearth slab, you won’t wait too long to float the surface, and you won’t have unsightly aggregate exposed like I do. Mixing one bag at a time in a puny electric mixer then shoveling or dumping buckets up into the form took me about an hour. By that time, I was unable to do an effective job of working the aggregate into the surface. I was using a scrap piece of 2×4 lumber, about a foot long.
I tried to keep the mix from getting too soupy, so maybe that helped the quickrete set up a little more quickly.
I have several leftover bags of concrete mix. I might try my hand at some countertops, but will practice with a single bag first, to get a little more familiar with the process.
I wrote that the hearth slab will not be seen by anyone, but I’m showing you mine anyway.