Kandla Grey Indian Sandstone rusting

[marblehead]

 

Hi guys,

 

Hope you're all well. I'm new here and searching for some advice and found this to be the best place so I'm hoping you guys will be able to help me out.

 

Recently, during lockdown etc. I've decided to do my patio at home with Kandla Grey Indian Sandstone. I found it helped me during lockdown and took my mind off everything (I had some personal issues to deal with and lockdown really didn't help at all.) I'm not scared of labour at all and found it really interesting. I learnt a lot. I've never done anything like this before but I studied a lot of videos and asked a lot of questions to people I know that are in the trade. I thought why not give it a bash myself and off I went.

 

I have done everything correctly. I dug out, laid a membrane, hardcore, vibrator plate etc. so it's all okay in that sense. I laid the flags on a full bed as advised and I was really pleased with the patio, it looked great.

 

However, before I came to seal it, I decided to clean it just once more before applying the sealer. To do this, I stupidly used brick acid which I now know is a big no no (sorry!). This has caused what I've found from research, rust to appear on the flags. I cannot get them to shift at all. I've tried everything, bleach, washing up liquid, all sorts! The only product that I have found does help is the following:

https://www.amazon.co.uk/Owatrol-Net-Tr ... 8983&psc=1

 

The Net-Trol appeared to help and I thought great so decided to buy some more to do the rest with it. Before I got some more, the stains started to reappear. I tried again with the Net-Trol but again, they just seem to come back. Is this because I am not sealing them immediately after?

 

Anyway, do you guys have any suggestions? Have you had this before and if so, what can I do to get rid of them? I'm absolutely gutted as I worked hard on this and was really proud of it but now I'm annoyed with myself for using brick acid on them and ruining them.

 

I'll post some pictures so you guys can advise. Any help is greatly appreciated so thank you in advance!

[marblehead]

[Temp]

Google suggests its not the acid but iron in the stone itself..

https://www.stoneworld.co.uk/faqs/how-to-remove-rust-staining-from-kandla-grey-paving/

 

 

Edited August 14, 2021 by Temp

[Temp]

Another suggestion here. Perhaps try on some left over stone first?

 

https://www.diynot.com/diy/threads/removing-rust-marks-from-indian-sandstone-and-general-cleaning.459264/

 

Rust is a pain to remove from paving and brick acid will not touch it. You need a specialist iron remover like lithofin bero or weiss rci

Kandla grey is one of the best indian stones in my opinion and i laid it at my own house. It will take bleach, mortar acid and pretty much anything else with no drama. Although always test on a corner first to be certain.

There are naturally occuring iron deposits in this and most other sandstones and the lithofin bero is designed for surface marks so may dull them but not completely draw them out if they are inherent in the stone itself.

 

[PeterW]

I got just off some paving where some screws had been left out in the rain using this stuff

 

https://www.screwfix.com/p/zep-calcium-lime-rust-stain-remover-1ltr/8679F

[marblehead]

Thanks for your suggestions guys, really appreciate them! I'll give them a bash and see what happens.

 

Thanks again!