Overheard a guy at the supply yard say he never uses a magnesium float on exterior work

He was picking up a load of fiber mesh and told his buddy that a steel darby gives him a better finish every time, even on driveways. I've always used a mag float for the first pass to avoid pulling up fines. This was at the Builder's Supply in Springfield last Tuesday. Has anyone else switched to steel for the initial leveling and seen better results?

4 comments

4 Comments

gracethomas1mo ago

My uncle in Tampa switched to steel years ago and swears by it for a slicker finish.

the_diana1mo ago

Honestly, that tracks. I've seen guys use a steel darby first to really pack it in before switching to a mag.

wells.christopher1mo ago

Yeah, I'm totally with that guy! I made the switch to a steel darby for the first pass on patios last season, and it just gets the surface tighter right from the start. You don't get that same loose, sandy layer to deal with later.

marybutler1mo ago

Switching to steel first sounds like a good way to trap bleed water and get a weak surface. That loose layer @the_diana mentioned is there for a reason, it lets you work the cream up later. A mag float lets the slab breathe on that first pass. Seen too many driveways with steel marks and scaling because it sealed everything in too fast. You get one shot at the base, and a mag is just more forgiving.