Shoutout to the old finisher in Fresno who told me to quit floating so wet
I used to jump on the float way too early, like right after the bleed water showed up, and my slabs always looked blotchy the next day. An old finisher in Fresno watched me work a 30x40 garage pour back in March and just said 'you're pushing water around, not cream.' I switched to waiting until the surface dulls and the thumbprint barely holds, then floated it with a magnesium float first. That one change cut my finish time by about 20 minutes per slab and the hard trowel marks finally went away. My customer even commented that the floor looked like polished glass compared to the last one I did for him. Now I want to know, do you all still float twice before troweling or just go straight to the steel once it sets up?
That line about pushing water around not cream is the whole game right there. Waiting for the surface to dull and the thumbprint to barely hold is exactly what more guys need to hear. Magnesium first is smart too because it opens the surface without dragging water back up. As for your question, I still float twice, mag then a steel float once it firms up, because skipping that second pass is how you get those dark spots and trowel burn later. Going straight to steel too early just traps water under the crust and it comes back to bite you at the hard trowel. Two floats cost you ten minutes but save you a callback every time.