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Heard a guy at the supply yard say he never uses a magnesium float anymore | Concrete Finishers - Librear

Heard a guy at the supply yard say he never uses a magnesium float anymore

He was buying a bunch of aluminum ones and told his buddy 'the mag just grabs too much on a hot day, makes it hard to keep it moving.' I've always used a mag float for my first pass, so that got me thinking about different mixes and weather. What's your go-to first float for a standard 4000 psi slab in warm weather?

3 comments

3 Comments

alice_mitchell5mo ago

My first pass is always with a mag, but maybe that's just old habit. The guy has a point about it grabbing on a hot day with a tight mix. For a standard slab in warm weather, I'll still start with the mag to pull up cream, but I keep a spray bottle handy to mist the float. If it's really cooking out, I might switch to an aluminum float for the second pass a lot sooner. It's a dance with the weather for sure.

thomasp445mo ago

You said you still start with the mag to pull up cream, but is that cream even worth it on a hot day? That tight 4000 psi mix can set up so fast that a mag float just tears the surface more than it helps. I grab the aluminum float first in warm weather because it glides without sticking, so I can work faster and get a cleaner finish before the concrete fights me. Why make the job harder by using a tool that's known to grab? The goal is a smooth slab, not just following old habits.

thomas835mo ago

Ever feel like your mag float is just a really expensive cheese grater when the sun's beating down? I've definitely been there, fighting a slab that's setting up faster than my brain on a Monday morning. You're right, sometimes the old way just makes you sweat more for a worse finish. I'll stick with the mag for that first pull, but I'm not too proud to grab the aluminum early if the concrete starts winning the fight.