Removing oil stains from concrete dock?

Johnboy · 07-04-2009, 05:27 AM

Last week after taking an oil sample from my port engine (about 6-8oz's) We determined that there was no water mixed in the oil. I wrapped an absorbent pad around the plastic cup and put it into a garbage bag with some other trash. As we walked from the boat to the trash cans, the oil dripped from a small hole and left a "bread crumb" trail right to my boat. I had no idea this was happening until confronted by the guys in the dock house the next day. Well by this time it had absorbed into the concrete. Scrubbing with Dawn and water removed some. Have tried some oil remover products but no luck. I did get some up with a pressure washer, but very little.
One guy at the marina has suggested Muratic Acid. I have used this to clean cement and remove grout from tile, not sure what to expect on oil removal. Any thoughts or suggestions? Any miracle cures? It seems that this would be a common enough occurance and could be dealt with simply.

Thanks,
John

NoFearEyes · 07-04-2009, 05:29 AM

Try Kitty Litter first--it will suck up the oil. I'd be careful with muriatic--it wil etch concrete and the oil is probably pretty deep./ Kitty Litter will suck it up then you can try next step.

Mr. Demeanor · 07-04-2009, 06:29 AM

Brake Clean and if that doesnt work, look up how to make a poultice for cleaning stone. It is what is used to clean oily stains from granite counter tops.

Chiefsurfer · 07-04-2009, 07:21 AM

I'd say that without chipping away the concrete, you're out of luck. Concrete continues to cure for more than 100 years. If it is on the concrete enough to be absorbed into the concrete, it is not a stain, it has become the concrete.

WhiteBucket · 07-04-2009, 07:41 AM

Muriatic acid will eat into the portland cement in the concrete and cause discolorations if you are not careful. Try a test spot in an area that is the least noticeable. If you go that route, I'd dilute the acid first. I'd start by mixing 1 part acid 4 parts water in a small plastic cup. Take a toothbrush or a small brush and dip some on and scrub. Make sure you rinse the spot well after you use it. If that didn't work, I'd decrease the water to three parts and repeat the process.

diminished-glutes · 07-04-2009, 08:01 AM

Instead of the acid, I don't believe that the oil will be soluable in it therefore no removal, try dawn dishwashing liquid and a stiff brush. The acid may do permanent damage to the concrete that is far worse than the oil spots!

Geonorth · 07-05-2009, 10:09 PM

Had the same problem on a new concrete dock I built. Best solution was to build a little "dam" around the problem area, pour in oil absorbant powder from car parts store and add a little solvent. Cover with plastic so it does not evaporate away too quickly. The oil will wick up into the absorbant material removing most of the stain. Follow up with hotwater and oxyclean which will bleach out the remainder with hydrogen peroxide.

Interesting fact I learned when I was in the oil business: A typical underground oilfield has about the same porosity as a typical concrete sidewalk - that's what holds the oil until it has somewhere better to go (ie absorbant powder, helped along by the capillary suction action of the solvent)

Mr. Demeanor · 07-05-2009, 11:07 PM

Quote:

Originally Posted by Geonorth

Had the same problem on a new concrete dock I built. Best solution was to build a little "dam" around the problem area, pour in oil absorbant powder from car parts store and add a little solvent. Cover with plastic so it does not evaporate away too quickly.

That is a poultice. Brake clean then poultice

DogTired · 07-06-2009, 05:10 AM

I had some sucess on oil in concrete by using a gel type paint remover. Brush it on let it sit, wash it off. I think it was made by Jabsco??? Gold colored can as I recall.

rcoleman · 07-06-2009, 05:18 AM

I do not get it.... why are you trying to remove the oil stain? I assume this is on a concrete dock? Are they worried about the environment or the "looks" of a few oils drips? I wonder what the EPA would think about have some of the above mentioned used and then washed into the water??

Sorry to sound like a tree hugger (I am not) but just thought about it as I read the post!

riverdiver · 07-06-2009, 05:32 AM

I removed my lower unit in my drive way last week and had gear lube all over by the time I was done. I use Westley's Bleche-wite it is a tire cleaner .(yes that is how it is spelled) let it sit for five minutes then scrub off with stiff brush and hose down. I have been using it for years on oil stains, and tires. I have used acid in the past but it will take off the face of the concrete. Chlorine for pools works good too.

Ed

Johnboy · 07-06-2009, 08:53 AM

Thanks for all of the suggestions. Some of the suggestions would probably have worked had I known about the leak in time. When I found out about it, the oil had soaked into the concrete.

Rcoleman, you're correct it is concrete and several of the suggestions would not be enviromentally safe. I'm not sure why all the concern, the docks are not spotless.

MrDemeanor, the drip is random and probably 200 yards long. I can't really get a poltice on it. It's not just confined to one area, more like a bread crumb trail.

Thanks for all of the suggestions,
John

billatstarbrite · 07-06-2009, 08:57 AM

Star brite Slime & Grime remover. It's powdered oxalic acid so you can use as much or as little as needed. Pur onto damp surface, srcub it in, let it sit, rinse it off.
It won't harm the dock but it will remove the stain.

wills · 08-08-2009, 05:53 AM

I've found an alternative to Pour N Restore and its called OIL GONE EASY HOME & DRIVEWAY S-200. It is effective on a variety of surfaces and it seems to work really well on concrete.
Visit the site for more details: Oil Gone Easy

Flot · 08-08-2009, 12:59 PM

Brake cleaner. I get oil on my paver driveway a few times a year and brake cleaner (you know, in the spray can from the auto parts store) is about the best thing for it. There are some "eco friendly" (hah) versions of it, they don't work quite as well. Of course the longer it sits the harder it is to get out, so good luck!