Cleaning concrete

[michael69]

Anyone know what is the best thing to clean oil stains and oil that's soaked into concrete. I bought some of the garage floor coating and need to clean the old oil stains the best I can. So I get the best results so it don't peel and flake. Any ideas appreciated.

[tsherry]

I use Simple Green, concentrate. I wipe it around the stain, let it sit for a couple hours and then wash it off. Works OK.

[basshound71]

I use a chemical called green clean which is similar to simple green.

[hivewax]

I tried the stuff to clean pools... think it's a reduced solution of Hydrochloric Acid. It makes the concrete pretty clean.

[70_F100]

You're probably going to have to etch the concrete to make the coating stick well.

I've always used muratic acid prior to coating a concrete floor.

[basketcase0302]

hivewax on Sun Feb 26, 2012 10:06 pm
I tried the stuff to clean pools... think it's a reduced solution of Hydrochloric Acid. It makes the concrete pretty clean.

Hydrocloric acid will take the meat off of your body, down to bones in seconds!

Muriatic acid is what's used to clean pool stains and also to clean concrete properly. When diluted with water and used properly nothing can compare.
The safety precautions for it are endless though, as well as exposure limits (must be well ventilated).

[70_F100]

When I was a teenager, I worked at a service station.

Every time we scrubbed the bay floors, we started with varsol (for the really bad spots), then but down concrete cleaner and finally poured the acid out of our old batteries and scrubbed all of this around. We then rinsed it all out the bay doors and into the sewer. Floors came out looking like new money!!

Probably not something you'd want to do today...

[Bob]

MAKE SURE YOU ADD THE ACID TO THE WATER... NOT THE WATER TO THE ACID. DO IT WRONG AND IT WILL ERUPT AND BLOW IN YOUR FACE...!!!
ALSO KEEP A HOSE HANDY AND SOME BAKING SODA SHOULD YOU HAVE AN ACCIDENT. WEAR A GOOD RESPIRATOR AND GOGGLES. EVEN REDUCED ACID CAN STILL BLIND YOU.

[michael69]

You're probably going to have to etch the concrete to make the coating stick well.

I've always used muratic acid prior to coating a concrete floor.

This is what I was thinking just didn't know what to use. Thanks

[hivewax]

Yeah, I forgot the stuff they sell at Home Depot is muriatic acid. Though, I was right... muriatic acid is a reduced solution of HCl acid.

I had to do a check to make sure - http://en.wikipedia.org/wiki/Hydrochloric_acid

[Kurt Combs]

I have used citric acid, which is also used to take stains out of fiberglass swimming pools.Try a small spot before you do the whole thing. Seems to me that I turned some concrete brownish using citric acid. Any acid works by stripping a layer of cement off of your concrete, so it will be rougher when you finish.

[Phil105]

Behr makes an etcher used for cleaning concrete floors - Home Depot has it.

[michael69]

I have used citric acid, which is also used to take stains out of fiberglass swimming pools.Try a small spot before you do the whole thing. Seems to me that I turned some concrete brownish using citric acid. Any acid works by stripping a layer of cement off of your concrete, so it will be rougher when you finish.

Is there anything I can use that won't make it rough, since the floor has been finished and is nice and slick. Don't really matter if the color is changed since I will be putting a colored coating on it anyway. Just want it to be clean as possible so it will stick and last a long time. Thanks for all you guys time and information.

[Kurt Combs]

Only the acids will make it rough. I would think a solvent (try acetone?) would drive the stain deeper into the concrete and give you a cleaner surface. Concrete is very porous and absorbs liquids, so I would use that to my advantage in this situation. Either try small spots with solvents or cleaners, or hope someone responds here that has worked with the same surface that you have.

[Phil105]

you want the surface to be somewhat rough if you are putting down a urethane floor coating - like U-coat It or something along those lines. The surface needs to be rough in order to get good adhesion.
I just had my garage floor done with a urethane coating and watched them closely. First they acid etched the floor and then used a diamond grinder on it. CLEAN it thoroughly with a pressure washer before putting your coating on.