Good morning,
we have a big problem.
We have some rust stains on our patio slabs, which are made of simple concrete pavers.
How and with what can we remove the rust stains?
Can you recommend a cleaner or a good household remedy?
The rust stains were caused by an iron-containing lawn fertilizer that spilled onto the patio, and we didn’t clean it up or didn’t notice it.
How would you proceed?
we have a big problem.
We have some rust stains on our patio slabs, which are made of simple concrete pavers.
How and with what can we remove the rust stains?
Can you recommend a cleaner or a good household remedy?
The rust stains were caused by an iron-containing lawn fertilizer that spilled onto the patio, and we didn’t clean it up or didn’t notice it.
How would you proceed?
First, my note on the (assumed) cause of the rust stains, which is said to be from an iron-containing fertilizer.
My response: impossible!
Reason: to oxidize iron(II) to iron(III) in order to produce visible rust, more than the 0.1–0.3% iron content in a mineral fertilizer is required.
It is more likely that iron components came from either the laying mortar or, more probably, the substrate (concrete or cement screed). These unavoidable iron-containing components are often found in the aggregate—and are permissible within certain limits.
Regarding the removal of the rust streaks:
Just last week, I was able to remove rust stains from a friend’s outdoor terrace within minutes using an aqueous oxalic acid solution.
Oxalic acid, a solid white powder, is also available online at a low cost.
Prepare about a 10% solution with warm water (note that it will not fully dissolve), and rub this solution into the “discolored” surface of the tiles using a soft wrist brush in circular motions.
After about 3 minutes, wipe off the dirty solution with a cloth and rinse the treated surface twice with clean water.
However, this method will not permanently eliminate the visible rust as long as there is still potential for rust in the substrate.
This means you will probably have to repeat the procedure after about one year. But I believe this first option is feasible and reasonable.
Because the alternative (option 2) is to remove the tile covering at the affected spots, eliminate the rust particles in the mineral substrate, seal the created recess with a reaction resin mortar, and reattach the removed tile.
I suspect option 1 is more practical in real life?
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Greetings to all: KlaRa
My response: impossible!
Reason: to oxidize iron(II) to iron(III) in order to produce visible rust, more than the 0.1–0.3% iron content in a mineral fertilizer is required.
It is more likely that iron components came from either the laying mortar or, more probably, the substrate (concrete or cement screed). These unavoidable iron-containing components are often found in the aggregate—and are permissible within certain limits.
Regarding the removal of the rust streaks:
Just last week, I was able to remove rust stains from a friend’s outdoor terrace within minutes using an aqueous oxalic acid solution.
Oxalic acid, a solid white powder, is also available online at a low cost.
Prepare about a 10% solution with warm water (note that it will not fully dissolve), and rub this solution into the “discolored” surface of the tiles using a soft wrist brush in circular motions.
After about 3 minutes, wipe off the dirty solution with a cloth and rinse the treated surface twice with clean water.
However, this method will not permanently eliminate the visible rust as long as there is still potential for rust in the substrate.
This means you will probably have to repeat the procedure after about one year. But I believe this first option is feasible and reasonable.
Because the alternative (option 2) is to remove the tile covering at the affected spots, eliminate the rust particles in the mineral substrate, seal the created recess with a reaction resin mortar, and reattach the removed tile.
I suspect option 1 is more practical in real life?
---------------------
Greetings to all: KlaRa
KlaRa schrieb:
Oxalic acid,The acid component in the removers that can be purchased.nordanney schrieb:
The acid content in the removers that you can buy.I admit, this response leaves me intellectually overwhelmed! “I”The acid content (…)” now needs an indication of WHERE. For example: The acid content in ....
But instead, we get: “The acid content in the removers (…)” The term “removers” is unfamiliar to me; written in lowercase, it seems to be an adjective, which does not fit the sentence structure.
Finally, the sentence continues: “The acid content in the removers that you can buy.” At this point, I am completely unable to grasp the intended meaning of the sentence.
Could “nordanney” please clarify in a more understandable way what he meant to express with his sentence (as quoted above)?
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Regards, KlaRa
C
chand19862 Sep 2025 21:57It is probably meant that oxalic acid is also an ingredient in commercially available rust stain removers for stones. Of course, it is not found in nail polish remover; that was just an example for the word "remover."
I quote Einstein: "Make it as simple as possible, but not simpler."
I quote Einstein: "Make it as simple as possible, but not simpler."
F
FrankChief3 Sep 2025 10:46So, it can only come from the fertilizer.
There is no other possibility, and it would be way too much of a coincidence.
I used the Mellerud rust stain remover, and it worked, but some stains that also look like rust don’t come off, and the purple discoloration no longer appears, so there is no more reaction.
My question:
Does anyone know a good, strong cleaner for concrete pavers that works for everything (not just for algae)? We hardly have any algae, or just minimal.
I need a cleaner that helps remove dust, grease, (possibly rust, brown stains), and other deposits from the stones.
Application: apply the cleaner, work it in with a brush, and rinse with water—please no pressure washer.
There is no other possibility, and it would be way too much of a coincidence.
I used the Mellerud rust stain remover, and it worked, but some stains that also look like rust don’t come off, and the purple discoloration no longer appears, so there is no more reaction.
My question:
Does anyone know a good, strong cleaner for concrete pavers that works for everything (not just for algae)? We hardly have any algae, or just minimal.
I need a cleaner that helps remove dust, grease, (possibly rust, brown stains), and other deposits from the stones.
Application: apply the cleaner, work it in with a brush, and rinse with water—please no pressure washer.