Why Grind vs Acid-Etch?

[kngelv]

Back in 2006 I acid-etched and put down Seal Krete Epoxy in my father’s garage. It is still holding up. The floor was 45 years old at the time and all I did was pressure wash then acid-etch. There were a few old oil stains too. This was well before I knew anything about diamond grinding and 100% solids epoxies. Thinking of putting down epoxy or polyurea in my garage which has fairly clean 40 year old concrete and wondering why I can’t just pressure wash and acid-etch instead of grinding. The only way I can do my floor is one half at a time which means I would have to rent a grinder twice. Thoughts?

James

 

[Garage Flooring]

Back in 2006 I acid-etched and put down Seal Krete Epoxy in my father’s garage. It is still holding up. The floor was 45 years old at the time and all I did was pressure wash then acid-etch. There were a few old oil stains too. This was well before I knew anything about diamond grinding and 100% solids epoxies. Thinking of putting down epoxy or polyurea in my garage which has fairly clean 40 year old concrete and wondering why I can’t just pressure wash and acid-etch instead of grinding. The only way I can do my floor is one half at a time which means I would have to rent a grinder twice. Thoughts?

James

Grinding, when done properly, is always effective at creating surface profile. Etching usually works, but there are circumstances it is not effective.

What you use is also a factor. For 100% solids epoxy you are going to get better adhesion if you grind. With a high solids Polyurea, etching is more than adequate.

 

[Shea]

Grinding is always the preferred method when applying a good quality coating if you want to ensure the best outcome. However, it's not always feasible for everyone to do so and is why acid etching is the best alternative.

This article explains some of the differences between the two.

https://allgaragefloors.com/grinding-versus-acid-etching-your-garage-floor/

 

[FJ4FUN]

One of our concerns with etching is making sure that the etchant is properly / thoroughly neutralized and proper rinse water pH is achieved prior to high pressure rinsing.

I'd also be curious as to know how you'd successfully etch one half of a garage at a time? Seems to me that covering and mechanically grinding may be "easier" than trying to target etch your floor? Not saying it can't be done but if I had to do the same I'd grind.

 

[LegacyIndustrial]

Etching does nothing for weakness in the the concrete surface.
Grinding helps to remove it.

 

[Armorpoxy]

Grind if you can. If you grind you need to use a matching epoxy primer to get good adhesion and prevent an uneven finish.

 

[kngelv]

I'd also be curious as to know how you'd successfully etch one half of a garage at a time? Seems to me that covering and mechanically grinding may be "easier" than trying to target etch your floor? Not saying it can't be done but if I had to do the same I'd grind.

I guess it would be a bit tricky. There is no way for me to put any coating on the whole garage floor at once. I have too much stuff to leave outside with no way to secure it while the floor cures.

James

 

[sberry]

I had intended on shot blasting and coating when I started but the deal fell thru. I wish I would have troweled again and finished smoother, some of it is ruff and is hard to sweep. I was thinking of a big rental grinder, what stone to smooth some?

 

[Armorpoxy]

Hi,
Diamond grinders use diamond blades referred to as 'tooling', not stones.

For heavy grinding to grind down broom and finish marks we would recommend a #30-#40. But...this will leave 'swirl marks' which you then will need to grind again with at least a #80 to remove them, and possibly up to a #120 depending on the thickness of the coating you are installing (thicker coating will hide more).

Make sure your grinder that you rent has a proper, self-cleaning vacuum otherwise you will have a huge cloud of dust.

Wear a respirator too as Osha has issued silica exposure rules from concrete dust.

Shot blasting can leave 'lawnmower lines' which often need to be grinded down depending on type of coating you will be using.

Our Prep-Crete Concrete Surface Division does a LOT of grinding and shot blasting so feel free to reach out to us directly if you need some more info on this. Thanks!

 

[LegacyIndustrial]

I had intended on shot blasting and coating when I started but the deal fell thru. I wish I would have troweled again and finished smoother, some of it is ruff and is hard to sweep. I was thinking of a big rental grinder, what stone to smooth some?

Rental grinders typically have 18-40 grit tooling.
You may have to buy the tooling for the rental machine.