Acid etched, prep question

[Ciontis]

Diy'er first time garage floor. Going to be using rust bullet duragrade coating on this floor. 2x. Flakes, clear coat with anti slip added.

Here are some after pictures of the prep and close ups of the really etched areas and some that I think might not be? I'm worried I didn't do enough etching and cleaning.

Process was as follows

This is model home concrete 1+ years old. No stains, cracks etc. I washed and scrubbed concrete. Then did 3 10x10 squares with a 3:1 water to muratic mix with what I thought was terrible results. Even though I'm not entirely sure what I'm looking for as a result. Some of the thicker areas I sprayed, you could really see the difference. So I figure that's what texture I should aim for? Can see in the attached pictures.

Following day I did a 50:50 mix. That seemed to work way better, I got yellowish foam and steam coming off the concrete. And these results seem much more favorable for getting a grittier surface. I heard to NOT let it dry, I had issues with this both days, had to go back and recoat areas so this wouldn't happen, and I prewet each 10x10 area. In a few videos I've seen, the guy coats the whole garage in acid and then washes it out. I have to assume he is letting it dry since these garages are larger than mine?

Anyway, after that last etch, I thought 75% of the floor seemed to be etched enough so I cleaned and power washed the garage twice. I'm now on day 3 of waiting for the slab to dry. Attached are pics. You can see where the power washer left marks, does that mean it's not clean enough for rust bullet? Should I power wash even more? Do I need to etch the floor more? Or will this be good for rust bullet?

 

[Shea]

Wow... You have gone way overboard on the acid etching. A 1-to-1 ratio (particularly after a 3-1 ratio) is far too strong and can damage the concrete. Did you neutralize at all or just rinse with water? If you didn't neutralize, I would suggest soaking the floor in a soap solution (laundry detergent) and then thoroughly rinse again. Soap has a high pH and neutralizes fairly well. Otherwise, the strong solution you used can continue working deeper into the concrete resulting in issues over time.

Why did you etch for Rust Bullet DuraGrade? It is one of the few coatings that does not require concrete prep in most cases other than cleaning. Rust Bullet encourages sanding of the surface or a very light grind if the surface has been power troweled or is extremely smooth for some reason. They do not recommend acid etching since it introduces moisture into the concrete. They have had delamination issues when people have not let the concrete thoroughly dry out.

DuraGrade typically needs a minimum of two color coats. However, you will most likely need an extra color coat. The coverage rate of the first coat is going to be reduced and will be very thin due to the profile you created.

 

[FJ4FUN]

We strongly discourage high pressure washing after acid etching especially if the acid has not been completely neutralized (and tested via pH test). The high pressure can force the acid deep into the concrete where it is tough to neutralize and will potentially attack the bond line from below of whatever coating you choose to apply at some point in the future. Neutralize with baking soda/water mix, or detergent as Shea has suggested, flood the garage with hose and city water pressure, and squeegee out rinse water. Repeat until pH range is 6.0-9.0 with 7.0 being ideal (for Wolverine BondTite primer anyway. Check with the manufacturer for whatever you're using). Once neutralized feel free to high pressure wash if you think you need to but be careful, freshly etched concrete is easy to slash and groove with a pressure washer.

 

[Ciontis]

Well, i tend to over do things... just figured the rougher profile would help adhesion. The concrete was power troweled and very smooth. Like a basement floor.

I forgot to mention, the first day I did not neutralize on the 3 10x10 squares, as the video I watched said throughly washing with water would work. The second day, I did use baking soda to neutralize the whole floor and scrubbed it in with a broom and washed and scrubbed and then washed. Power washed twice after that.

So now what? Should I do some ph tests or calcium tests? It's been drying for 4 days now. I have a fan going. Would love to be able to coat this weekend. But I'll do what I have to do, to make the floor ready for proper adhesion.

Thank you for your replies

 

[Ciontis]

Wow... You have gone way overboard on the acid etching. A 1-to-1 ratio (particularly after a 3-1 ratio) is far too strong and can damage the concrete. Did you neutralize at all or just rinse with water? If you didn't neutralize, I would suggest soaking the floor in a soap solution (laundry detergent) and then thoroughly rinse again. Soap has a high pH and neutralizes fairly well. Otherwise, the strong solution you used can continue working deeper into the concrete resulting in issues over time.

Why did you etch for Rust Bullet DuraGrade? It is one of the few coatings that does not require concrete prep in most cases other than cleaning. Rust Bullet encourages sanding of the surface or a very light grind if the surface has been power troweled or is extremely smooth for some reason. They do not recommend acid etching since it introduces moisture into the concrete. They have had delamination issues when people have not let the concrete thoroughly dry out.

DuraGrade typically needs a minimum of two color coats. However, you will most likely need an extra color coat. The coverage rate of the first coat is going to be reduced and will be very thin due to the profile you created.

I replied below. Thank you for your time

 

[Shea]

Well, i tend to over do things... just figured the rougher profile would help adhesion. The concrete was power troweled and very smooth. Like a basement floor.

I forgot to mention, the first day I did not neutralize on the 3 10x10 squares, as the video I watched said throughly washing with water would work. The second day, I did use baking soda to neutralize the whole floor and scrubbed it in with a broom and washed and scrubbed and then washed. Power washed twice after that.

So now what? Should I do some ph tests or calcium tests? It's been drying for 4 days now. I have a fan going. Would love to be able to coat this weekend. But I'll do what I have to do, to make the floor ready for proper adhesion.

Thank you for your replies

Yes, I would recommend pH testing first. You also appear to have areas where there may be a white powdery residue. This can develop if you wait too long before neutralizing and rinsing. Rub your fingers across those areas. If you get a lot of that residue on your fingertips, then you will need to scrub it off and rinse again.

 

[Armorpoxy]

Prep only needs to have the surface textured at a microscopic level so the coating can adhere, it doesn't need to be gritty or very rough for a standard liquid epoxy to adhere properly. Often we find overworking of floors which is unnecessary. Per above, check PH make sure the floor is well cleaned and dry before coating.