Is grinding overkill MCU

[podium804]

Hey there Garage Journal. I'm leaning towards an MCU for my old floor. Rust Bullet Duragrade specifically. If I wanted to just knock this rough patch down smooth, would you still get a grinder or is there like a floor buffer with a sanding pad that could work.? It's really only in this area. The rest of the floor is finished quite nicely.
Thank you!

 

[DaChev]

I have been using these to work my floor to a semi-polish before coating with a Polyurea. They are extremely effective. It looks like you would need to start at a 50 or so, because your floor is very rough.
Concrete DNA
They do a great job of cutting and polishing at a cost that is bearable.

If your goal is a completely flat floor, you will likely need something with a more rigid backing to begin. I suspect that something like this would help for the first cut if you are obsessed with the flatness of the floor.
Diamabrush

 

[ryanmworkman]

The only way to really ensure a good bond is through mechanical preparation, so not doing that is going to be a risk.

Even if it sticks, it is up to you whether you are okay seeing those trowel lines. MCU is applied very thin, so even the smallest imperfections are going to be visible. Typically, when we do a urethane floor system, we are doing a two step grind to 100 grit for a smooth finish.