Odd Appearance / Texture After Etching

[Sigma]

Got to etching the floor this evening and had some sizeable areas of the garage floor that have an unusual 'speckling' thing going on. Just wanted to make sure this isn't something I need to find a workaround for.

The dark gray areas seem 'etched' to me. The texture appears a bit rougher than the other sections of the garage I haven't gotten around to yet. But the light grey areas that were always there, but REALLY "popped" after the etching are quite a bit smoother. I'm just assuming it's aggregate in the concrete, but that's really just a total guess on my part. This 'stuff' appears mostly in the areas of the slab that had to be ground down to achieve the slope. It's got 1-bay (equivalent) without a door with no slope (i.e. a workshop area), the other 2 bays are sloped and you see a lot more of this phenomenon in that area, while the 'workshop' bay is a very uniform dark gray.

 

[Antoddio]

What are you etching for? If for a coating, that stuff is going to peel up pretty quick.


Sent from my iPhone using Tapatalk

 

[ForceFed70]

For those who cannot view the pics. Here are links.

http://i.imgur.com/K7uVlQL.jpg


http://i.imgur.com/bXzLvHG.jpg

 

[Shea]

For those who cannot view the pics. Here are links.

http://i.imgur.com/K7uVlQL.jpg


http://i.imgur.com/bXzLvHG.jpg

Not working

 

[Sigma]

No idea why some aren't seeing the photos. I shrank them way down so they'd fit in the allowable size range as direct images to this post.

And, yes, I'm etching to apply an epoxy coating.

 

[Antoddio]

No idea why it's like that, but doesn't surprise me, concrete is affected by a variety of things. I'd grind or shot blast unless you plan on redoing your coating in 2-3 years.

 

[LegacyIndustrial]

Looks like a sheen is present. Grind that floor.

 

[Shea]

I agree with Scotty. It looks like the floor may have been treated with a "cure and seal" additive after the pour. When something like that is used you will need to grind the concrete. Acid does its job by reacting with the free lime in concrete. If there is some sort of sealer at the surface or even remnants of a sealer, the acid will not react well if at all.

 

[Sigma]

Well, the "sheen" is probably because the floor was still wet from being rinsed from the acid solution.

But, regardless, I'm leaning heavily towards just grinding anyways. The way the floor reacts somewhat erratically with water sprinkled on it is a bit worrisome (the acid was definitely reacting too so def not a solid seal involved, but didn't seem to be reacting uniformly) and makes me think a "cure and seal" situation is likely. The only thing that makes me hesitate at all is that I probably won't live here more than a few years anyways, so to some extent "good enough" is just that. But given that rental from HD is <$100, I guess there's really little reason I shouldn't have just started there in the first place given the time "wasted" with etching.

For those that have etched who may still be reading this far -- is dust control a serious problem? I've got other items in the garage that are shifted to work around and fresh paint on the walls. With enough water and a dust vac, can the dust be largely mitigated or am I going to be scrubbing walls to get concrete dust off?

 

[Shea]

You will want to use a vacuum system if grinding dry. If not, you will be wiping concrete dust off the walls and anything else it can settle on. Either way, make sure you are wearing a respirator or dust mask with an N95 rating.

If you grind wet you will have zero dust, but it's extremely important not to let the slurry dry on the concrete. If you do it's a huge chore to get the concrete clean. Grind a small 4x4 area wet and then hose it clean. Work in sections like that and you will fine. Be sure to tape some cheap plastic drop cloth sheets about 3' up your painted walls. Just be aware that the slurry you hose out of your garage can make a mess if it's not contained to an area where it can dry and then get swept up.

 

[Armorpoxy]

If you suspect a sealer was used, definitely grind, Shea is right on. The secret is always in the prep.