Roughness of floor for epoxy?

[nate379]

Wondering how rough the slab should be for epoxy?

I washed my floor several times to include hydrochloric acid etching. It was power toweled to begin with so nice and smooth.
It’s got a bit of texture to it now, but it’s not like a slab that was just bull floated or hand troweled.

I’m almost thinking of seeing if I can track down a slab grinder… but I don’t know really if I should spend the time and money with it… and even if it will do what I need?
Are you guys using the grinder to level out the floor or to rough it up?

Is there a good guide to how rough the slab should be?

 

[AlphaGarage]

The rule of thumb is that it should approximate the texture of 80 grit sand paper.

 

[nate379]

Yeah it's maybe 300-400 grit sandpaper right now.

Grinder will rough it up??

 

[krooser]

Geez.... I sanded my floor to make it smoother. Think about those polished floors you see at the box stores...

 

[nate379]

Ok.... so what the heck do I use to rough it up then?

 

[AlphaGarage]

What kind of reaction did you see with the muriatic acid? Could you see/hear the acid doing it's thing? Was the solution strong enough?

 

[nate379]

I just went back a bit ago and put it down on a square (garage is cut into 4) at 100% right out of the jug and let it sit for 30 mins. It seems that it worked out nicely. Just have to go get more acid and do the rest I suppose... would have been easier to do that right from the get go! ARGHH!!!!!

I had mixed it 1 quart of the acid to about 3 quarts of water before. Followed the directions on the jug.

 

[thegarageguy]

Find a grinder rental with diamond inserts and a hepa vac. Acid is way too inconsistant and may result in future failure.

 

[wildcat12]

it should be relative to thickness of the coating you are applying, the thicker the coating you are applying the more profile you need. I am guessing you are applying 10 mils or less so a profile like 80 to 120 grit sanpaper will be fine. Concrete has pores like your skin and you need to expose those pores so the coating will penerate to achieve a mechanical bond, so simply drop a little water on the concrete and see if it penatrates, or simply beads up