Floor Prep -Sanding & etching

[mxgo]

In preparing the floor for the epoxy coating primer, is sanding sufficient or do you also have to do the etching?

A friend who just did his floor said that forums for professionals said that sanding was better than etching for preparing the floor for the epoxy and they did not do etching. I believe he also said that others said the opposite.

I do understand that the acid etching does change the ph of the concrete surface. Is this a factor for the epoxy primer?

My floor has already been sanded.

 

[Irondrive]

Sanding is not sufficient. The best prep is diamond grinding or shot blasting.
There are tons of threads on this topic.

 

[AlphaGarage]

The ideal is to have the texture of the concrete feel like 80 grit sandpaper.

Grinding with the correct media is almost certain to work, but that's if the floor is somewhat level to begin with. Aggressive grinding can level out high spots, but don't assume that it's quick work.

A new pour will have that 80 grit feel if you spec a "light broom finish" and the contractor knows what they're doing. But even then a acid etch is recommended.

We have pro installers who have no qualms against using just an acid etch for prep work, especially if the floor is in good condition.

It all depends on what shape the floor is in.

 

[SUPERCOAT]

We don't recommend acid etching on a floor unless it has a very smooth finish (in which case you need to profile the concrete). Cleaning THOROUGHLY with our degreaser and sanding the tire lanes has proven sufficient for SUPERCOAT.