Removing Rust from Concrete

Tejs

So I forgot to brush off fertilizer I used for my lawn on my driveway and sidewalks. I've tried CLR rust removal (it said I could use it on concrete), with pretty much no result.

Everything online says I simply have rust on the concrete (especially since I bought a high iron fertilizer), so what products do you use to get rid of these stains and how do you use them? I have a lot of concrete basically sprinkled with these stains, so a large scale solution would be greatly appreciated.


This is a decent approximation of my problem, just more clustered and deeper orange.

wmelon

Do you have access to or the desire to rent a pressure washer? soaking it with the clr and then using the pressure washer ought to get that off.

Tejs

Perhaps I could. However, I'm looking first for a less involved solution. Been googling since posting this question, and it seems there are spray alternatives that remove it right before you eyes:

http://www.youtube.com/watch?v=kRd9MiyRd-s

Who knows it actually works as advertised though...

bowen

Might be cheaper to just resurface the concrete or something, but if CLR didn't get it, it probably isn't coming out.

L Ron Howard

Why do you want to remove the rust like that?
I mean, most everyone I know has some rust spots here and there on their concrete surfaces, and everyone just leaves it there. I guess, it does seem to be a weird request, to me.

Tejs

You don't think it looks nasty?

bowen

Nah looks like you made an effort to clean it. It's not a big pile of dogshit, so, on a scale of 1 to what the fuck, it's about a 2 or 3.

Page-

If you're really insistent on getting the stains off then there are 2 extreme methods you can use.

The first is a grinder. This will get the stains off, but it'll still look like ass and they can be hard to use properly.

The second is muriatic (hydrochloric) acid. A diluted solution of this, a good brush or broom, and plenty of water is sometimes used by professionals to clean bricks or other masonry. It's nasty stuff, and dangerous enough, but it will eventually get the job done. However, it will effectively clean whichever spots you want to the point where they'll stand out just as much as the rust spots do, so depending on how particular you are about the overall look of the surface you may end up having to spray the whole thing with acid.

And at the point where you're ready to use acid you may as well pressure wash it, though that will probably be more expensive.

Apparently you can also use trisodium phosphate, but I've never worked with that stuff.

Forbe!

What page said.

Muriatic acid is a type of hydrochloric acid used for pool cleaning and concrete etching.

I've worked with Muriatic frequently in metalworking, and it dissolves iron alloys rapidly in a concentrated form. YMMV.