How clean before etching concrete?

[mfive]

Hi all,

I'm prepping my floor to get ready to epoxy with epoxy-coat. I hav areas where the previous owner's car leaked oil. It was dry before degreasing, like it had been some time since the car was leaking (I just purchased the home).

My question is, I just did a full degrease of the garage, working the degreaser into the concrete with a large broom. I then rinsed it with my power washer and tried to get up anything on the surface (paint drips, etc.).

It definitely looks lighter and cleaner, but the oil stains are still visible. Is it even possible to get these out 100% or is that something that the etching will help with? Should I worry about degreasing again?

 

[93sr20det]

I am sure you can find it cheaper but Griots Garage has something that you let sit on bad stains then you rinse it away.

http://www.griotsgarage.com/product/concrete+stain+rust+remover.do?sortby=ourPicks

http://www.griotsgarage.com/product/concrete+cleaner.do?sortby=ourPicks

 

[mfive]

Thanks for the tip! I just got back from my local big box and got some more degreaser. Wish I would have seen your post before leaving. I'm going to degrease one more time.

Is it normal to not get the concrete looking brand new before coating? I find it hard to imagine that everybody's concrete looks like bare concrete before putting down an epoxy coat.

Hopefully one more degrease will do the trick, then off to etch after it's dry.

 

[mfive]

Just spent the last hour degreasing and power washing again...

This time I used: http://www.lowes.com/pd_276151-3422...currentURL=/pl__0__s?Ntt=degreaser&facetInfo=

It seems to have left some type of very thin layer of wax or residue on the concrete that I can see when I was powerwashing. (It was like the water was "wicking" over it, much like you see with Rain-X on a windshield but not nearly as bad). Hard to imagine a degreaser leaving a residue, but now I'm worried I maybe should do it again!?

I used Purple power the first time, and that didn't leave anything behind... Should I do it again, or let it dry and see how it looks?

 

[Edger]

I would be surprised if that residue stopped the etching process so it is probably not worth doing it again although a test with the etch should give you an idea.
Some degreasers tend to dissolve the oil into suspension in water and some are emulsions in a solvent which do leave light residues because they never fully mix with the rinse water.
If you want a quick way to remove more of the oil stain use a solvent like a thinner or turpentine on top of cat litter (the clay type) on top of the stain. Cover with plastic and leave for an hour. Next sweep it up and sprinkle water on the stain with laundry detergent and mix it in with a broom. Leave for 10 mins and wash off.
Often you cannot remove all the stain because the oil has mixed with dirt and both have seeped into the concrete. If the surface is clean with no water beading before coating then the epoxy will adhere strongly and the stain will never be a problem.

 

[93sr20det]

Maybe you should try this:

http://www.lowes.com/ProductDisplay?partNumber=224240-4-002.0000096.007&langId=-1&storeId=10151&productId=3108525&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1