Removing fuel stains from concrete

[vorlon1]

I've searched here and other places--perhaps my Google-fu skills are current/proficient--but can't find the answer to the following:

     Is there anything that can remove fuel stains from concrete? 

As you might expect, I've found lots regarding removing it from your airplane, but on concrete, not so much.

See sometime back my fuel drain(s) had a slow leak that produced some fairly impressive stains on the concrete floor of the hangar; and with winter coming on and me looking for another reason to hang at the hangar, I began trying to remove them. HA! 

So far I've tried:

• paint thinner,
• gasoline, and
• on the presumption that it just might dilute itself, more avgas. 

Always using a brillo-pad sponge thingy and scrubbing hard with my foot I've experienced very little in the way of success.

I'm open to ideas and I'm willing to try pretty much anything short of nitroglycerine since it seems to be in hard to find here with the supply chain problems and all...

Does anyone have an idea as to what the 'secret sauce' might be?

[PeteMc]

Try adding small amounts of water a LOT of times.  No point in just letting the water run non stop, but every couple of minutes while you're there open the hose to get the area wet or pour a little water out of a bucket.  Once the concrete has absorbed a fair amount of water, then dump a pile of cat litter on the stain.  Probably have to exchange it with new a few times.  Maybe once a few hours after initially putting it down, then again the next morning.

If the concrete itself has not already been discolored, the cat litter may suck up some of the fuel as it suck the water out of the concrete.

Jackhammer and a concrete mixer works too....

[DonMuncy]

Sulfuric acid will almost certainly take them up. Other acid products probably will also.

[vorlon1]

1 hour ago, DonMuncy said:

Sulfuric acid will almost certainly take them up. Other acid products probably will also.

Great suggestion. I have some sulfuric acid here from my pool ops.

I'll try that and report back...

[Pinecone]

Dawn and water.  

You need a surfactant to allow the water to remove the petro.  The dye stain may never come out.

Cement/concrete is porous, so things soak in.

The other option is to paint the floor.  When I did my detached garage is this - https://ucoatit.com/getstarted-gad/?gclid=CjwKCAiAvK2bBhB8EiwAZUbP1BA2w7ME0n9pNAHJDkJi0Q65knTIK6FrmuGeVRri40TJCOMdrwlyrhoCQlsQAvD_BwE

It is a water based epoxy.  The first coat has an additive and it is applied to damp concrete, and actually soaks into the concrete to bond.   I pulled a loaded metal shelf unit across it and it ground the paint, off the shelf unit.  It is not hurt the coating.

[Pinecone]

FYI, I would not use sulfuric acid.  For cleaning/etching concrete, you use muriatic (hydro chloric) acid.

[N201MKTurbo]

MEK or Lacquer thinner will dissolve the fuel stains. the trick is keeping it from re-sticking when it evaporates. I would use a chip brush to scrub the solvent into the stain and paper towels to soak it up while it is still wet. To get the last little bit, I would scrub in the lacquer thinner, then hit it with dish soap water and a scrub brush.

[N201MKTurbo]

Be careful acid washing concrete. I showed my wife how to do it. She went crazy and scrubbed the back patio.....to death. It looked great when she was finished, but after a few months the concrete started to deteriorate quite severely. I asked her how much acid she used? I told her to use about 2 cups in a bucket of water. She said that wasn't working very fast so she added a bunch more.

I need to have it all taken out and replaced.   Perhaps I will tile it.

[Shadrach]

Do you have access to water for a pressure washer?  I would soak the affected area with MEK.  Cover if needed to prevent evaporation. Pressure wash after it has been allowed to soak for 5-10 mins.

[Will.iam]

Use nail polish remover before trying acid. Neighbor had a bottle of muriatic acid that the bottle leaked out. It destroyed his concrete. Literally turned it into rubble moral of the story don’t store acid in the garage. 

[Pinecone]

As was mentioned, it is like 2 cups of acid to a gallon of water.

And ALWAYS ADD THE ACID TO THE WATER.

[PeteMc]

11 hours ago, Will.iam said:

It destroyed his concrete.

I've heard of using a diluted acid wash for cement or concrete with a high content of cement mixed in to make it denser.  But if we're talking basic concrete, the acid usually is absorbed into the more course material and then starts to break it down. 

 

[Shadrach]

Acid should be a last resort.  A good solvent and a pressure washer should do the trick with minimal damage to substrate if used properly. 

[jaylw314]

A good soak in some half-strength Simple Green and a pressure washer is usually a less unpleasant experience...

[Utah20Gflyer]

19 hours ago, Pinecone said:

FYI, I would not use sulfuric acid.  For cleaning/etching concrete, you use muriatic (hydro chloric) acid.

Yes!  Muriatic acid is what is used to clean concrete but be careful with it,  that stuff evaporates into the air easily and you don't want to breath that stuff in.  I've had a couple instances where I got a big whiff of it and it's not something you want to do. 

After though make sure to use a sealer to help prevent future stains.  Concrete is quite porous and will readily stain.  A sealer will greatly reduce surface porosity. 

[Pinecone]

You acid wash fresh concrete to neutralize the excess alkaline.

Excess alkaline exudes from the concrete and will lift any paint that you apply if you do not acid wash.  But again, about 2 cups per gallon of water.  Spread it around and very quickly the acid and alkali neutralize each other and all you have is water with some salts in it.

 

[Pinecone]

Just now, Utah20Gflyer said:

After though make sure to use a sealer to help prevent future stains.  Concrete is quite porous and will readily stain.  A sealer will greatly reduce surface porosity. 

This is why I mentioned painting it. 

The U-Coat-It in my garage has been down for 20 years and is going strong.   I only put down the color coat, I did not add the clear coat (most slippery) so it does show some grime.

[vorlon1]

2 hours ago, jaylw314 said:

A good soak in some half-strength Simple Green and a pressure washer is usually a less unpleasant experience...

Do'oh! I forgot to include Simple Green in the list of things I've tried. Up to and including full strength. This was my first attempt and was surprised it didn't work. 

[vorlon1]

19 hours ago, Shadrach said:

Do you have access to water for a pressure washer?

I do. However access to water at the hangar is 'tricky',  so that's my last my last resort.

Thanks for the suggestions and keep 'em coming.

[Fly Boomer]

6 hours ago, Shadrach said:

Acid should be a last resort.  A good solvent and a pressure washer should do the trick with minimal damage to substrate if used properly. 

Depends somewhat on the pressure washer.  I have seen one damage concrete.  Either too strong pressure washer, or too weak concrete.

[N201MKTurbo]

I bought my son a bad a$$ (its not a bad word if you use special characters) gas powered pressure washer for his birthday a few years ago. If you put its nozzle less than 2" from the concrete, you can write your name in any concrete.

I could probably remove all the concrete in the back patio with his pressure washer. Jack hammers are so noisy...

[Yetti]

Nail polish remover is Acetone.    Don't do this, but some more gas and then light it will get rid of it.   Most people pressure wash their concrete too much and take off the protective layer.   I would try Goop hand cleaner.   Do the belly while you are down there.

[Schllc]

On 11/9/2022 at 6:03 PM, Pinecone said:

FYI, I would not use sulfuric acid.  For cleaning/etching concrete, you use muriatic (hydro chloric) acid.

I wouldn’t put acid anywhere near my airplane, even in a bottle, especially Muratic. 
I put a unopened bottle of Murat if acid in an aluminum toolbox in my truck one time and forgot about it. 
the. One day driving I heard a clunk. When I stopped and looked the entire floor of the tool box had corroded. 
It will rust (yes aluminum rusts too) any metal in its proximity

it cleans concrete by dissolving the calcium. It will damage the concrete and it’s very difficult to off gas completely after using. 

[Pinecone]

There is no off gassing if it is used correctly.  It reacts totally to become salts and gasses.

Calcium carbonate and HCl becomes Calcium chloride and CO2.

The CO2 is why it foams when reacting.  When the foaming stops there is no HCl left (unless you use so much there is no concrete left ).

[Schllc]

I’m not arguing the chemistry, but maybe the duration of the reaction.  
Feel free to use in the vicinity of your thin skin aluminum aircraft at your peril.