To grind or not to grind?

[ELS]

All,

I know this type of question has been asked many times but your input is greatly appreciated. Newer home, built late 2003. 32 x 21 attached garage. No cracks, no water (plastic test) and no visible oil/grease stains. Garage is mainly used for parking two cars and light repair work, tire rotations, maintenance, etc. Will be using solvent based 2-part primer, epoxy and clear coat. Should I:

1. just chemical clean and muratic acid
2. diamond grind ($150 rental)
3. Have experienced contractor bead blast for $300

Again, the floors are in great shape and I want this epoxy to last, but just wondering if grinding or bead blasting is necessary.

What do you guys think?

 

[dlr944]

Personally, I would diamond grind or shot blast the floor. I have a newer home and performed a few car projects in the garage and cleaned the surface throughly before appling my flooring but any contaminants will cause the the epoxy floor to "fish eye". I would diamond grind if I every do this again.

 

[AlphaGarage]

You will probably be fine with a chemical etch.

Muriatic acid is no doubt the most common chem method. It works by reacting and dissolving the calcium in the concrete while leaving the other components largely unaffected.

When the acid is spread onto the concrete you should hear and see the interaction. If it just sits there, like water, you may need a stronger concentration. If it smokes, it's too strong and you should dilute it a bit. Do not let the solution dry out, after the acid's played out, and there isn't any more reaction (about 15 minutes), dilute it with lots of water and rinse it out well. And rinse again, a pressure wash is even better.

Then check the concrete, it should have a rougher texture, ideally one that feels like 80 grit sandpaper.

Some floors will require more than one acid application.

Keep in mind that muriatic acid is a very caustic chemical! You must carefully read and follow all directions and precautions! Besides being a health hazard it's also very corrosive to many metals. So much so that if you have a lot of machinery or other metals you may want to avoid muriatic acid all together.

There are alternative chemicals (we offer OrganiPrep 921) that will do the job but without many of the nasty side effects, but they will cost more.

 

[ELS]

Thanks DLR944 and Alphagarage, would the cleaners/acid etchers eat away at any oil spots or the rubber type marks from auto's? Or should I just grind away to ensure a fresh clean layer?

Thanks again.

 

[Scotto]

I'd just etch it. In my dad's 25 yr old, VERY well used garage we just used the muriatic acid after some degreasing. We used the cheap Rustoleum water-based epoxy and there's been zero lifting problems after 5 or 6 years.

 

[ironroad 9c1]

yup , that's all I did , after cleaning the really bad oil stains with the zep citrus cleaner and purple cleaner, and its been on almost a year,I did the solvent based rustolium on one side and a product called Cantol on the other side, both had been fine, I have dropped several thing and its chipped the coating , but it is not peeling or giving way .

 

[StangRacing]

if i had a brandnew shop 30x30 I am now looking at a epoxy kit
would the cleaning supplys in a kit such as epoxy coat have everything I need to clean and apply