What Works to Remove Rust Stains from Concrete

gjrepesh · May 22, 2019

I had some metal items on the driveway for a long time. I finally moved them and now have rust stains on the driveway. What have you used to successfully remove rust stains from concrete?

DMF_TomB · May 22, 2019

gjrepesh said:
I had some metal items on the driveway for a long time. I finally moved them and now have rust stains on the driveway. What have you used to successfully remove rust stains from concrete?

.
hardware stores sells stuff to remove rust caused by rusty water from lawn sprinklers on concrete. have no ideal what it actually is

rons · May 22, 2019

Muriatic acid will do it. Dilute it by 50/50 or less. What you will get is a bright clean spot that does not match the age of the surrounding concrete.

DMF_TomB · May 22, 2019

might be oxalic acid
.
Cleaning
Oxalic acid's main applications include cleaning or bleaching, especially for the removal of rust (iron complexing agent). Its utility in rust removal agents is due to its forming a stable, water-soluble salt with ferric iron, ferrioxalate ion.

DDoug · May 22, 2019

A jackhammer.....and a premix truck soon afterwards with 10 yards in it.....

Seriously, there is a growing business in concrete staining, see
if the rest can be stained a dark color to match.

As said above, the cleaned area's won't match the rest.

DMF_TomB · May 22, 2019

hardware stores sell alot of stuff that is milder and basically bleaches stains from iron and mold. more of a color change
.
basement black mold they sell stuff you spray on and in a few hours its gone or rather its bleached so not easily seen. it does not destroy wall or dissolve concrete. its like removing paint. stores sell milder stuff where it gets soft and can be scraped off without destroying whats underneath

ticticdoc · May 22, 2019

CLR it is calcium lime rust removable.

LatheWerks · May 22, 2019

Search "Whink rust remover" on Amazon. It's 1-3% hydrofluoric acid. I use it to etch titanium.
Be extremely careful with it as it'll seep through your tissue and bond with the calcium in your bones, pulling the bones apart slowly and invisibly. Wear nitrile gloves inside thick rubber gloves and fully clothe your body to avoid splashing.

Booze Daily · May 22, 2019

LatheWerks said:
Search "Whink rust remover" on Amazon. It's 1-3% hydrofluoric acid. I use it to etch titanium.
Be extremely careful with it as it'll seep through your tissue and bond with the calcium in your bones, pulling the bones apart slowly and invisibly. Wear nitrile gloves inside thick rubber gloves and fully clothe your body to avoid splashing.

I think I’d rather have rust stains.

DDoug · May 22, 2019

LatheWerks said:
Search "Whink rust remover" on Amazon. It's 1-3% hydrofluoric acid. I use it to etch titanium.
Be extremely careful with it as it'll seep through your tissue and bond with the calcium in your bones, pulling the bones apart slowly and invisibly. Wear nitrile gloves inside thick rubber gloves and fully clothe your body to avoid splashing.

and what about your lungs ?
eyes ?
and where is this stuffing getting washed down to ?
Storm drain ?

Leave it in the bottle

MrSteve · May 22, 2019

Booze Daily said:
I think I’d rather have rust stains.

I KNOW I’d rather have rust stains!

That said, I’d try oxalic acid.

Mark Rand · May 22, 2019

Even oxalic acid needs a poisons license for concentrations over 10% in the UK.

To be fair, it is poisonous...

Rob F. · May 22, 2019

Oxalic acid is the main ingredient in barkeepers friend.
I use it on stainless jobs and tell the client that is what they should use to keep stainless clean. Never tried on concrete, I would use the liquid formula.
Bar Keepers Friend cleansers | Once Tried, Always Used

lionelt · May 23, 2019

Any reason for not trying a pressure washer first?

indianamoon · May 23, 2019

We have very rust water in our neighborhood and I use the diluted muriatic acid

Greenwud · May 23, 2019

CLR is Sulphamic acid, also sold as radiator flush

A needle scaler is remarkably effective too...

gjrepesh · May 23, 2019

Pressure washing did not remove the rust stains. I'll try the muriatic acid first. Not concerned about a little color difference. Its a driveway. Over time I'm sure things will blend. Thanks.

DMF_TomB · May 23, 2019

obviously many things like acids and bleaches are hazardous.
.
and many items are not that caustic but can still be hazardous. weed and pesticide chemicals and garage chemical like anti freeze can be very hazardous.
.
i used to do darkroom photography and one day i notice statue in small fish tank on its side so i stick my hand in and put it back top side up. within a minute fish starts doing circles and another minutes its on its side dead. my fingers had a little chemical on them from my moving photographs in the darkroom chemical trays. for years chemicals never bothered hands but obviously it was hazardous. used tongs from then on avoiding getting chemicals on my hands
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another example is mushrooms. every so often you hear a woman collected mushrooms and fed her family a meal and they all got sick and died. the wrong mushrooms can be toxic but not caustic. just cause its natural doesnt mean its safe

Pathogen · May 23, 2019

Iron Out, Powder, Mix with water, available everywhere, don't breath vapors

DMF_TomB · May 23, 2019

farmers who irrigate minimum water amounts find eventually soil increases in arsenic and selenium and salts and it eventually poisons the land. excess water flushes away the salt and mineral buildup.
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even salt water from the natural ocean if you irrigated the land with it the salt buildup would stops most plants from growing
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all natural and obviously most anything can be hazardous

What Works to Remove Rust Stains from Concrete

Cast Iron

Diamond

Diamond

Diamond

Diamond

Diamond

Aluminum

Cast Iron

Titanium

Diamond

Aluminum

Diamond

Diamond

Stainless

Aluminum

Hot Rolled

Cast Iron

Diamond

Hot Rolled

Diamond

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