tommy dee Posted January 18, 2020 Share Posted January 18, 2020 you may or may not know that concrete here is never sealed and of course a few pressure wash cleans takes the natural membrane off, making it porous. after a while oi, paint what ever gets splashed on it I am gonna seal a large area, sandwashed but cant figure out what to use to get the stains off first. thinners doesnt work, should I use acid? any clues? cheers Link to comment Share on other sites More sharing options...
Freee!! Posted January 18, 2020 Share Posted January 18, 2020 Don't use acid, it will dissolve the concrete. Link to comment Share on other sites More sharing options...
Toy Boy Posted January 18, 2020 Share Posted January 18, 2020 It'll depend on what caused the stains. Did you try warm water and soap yet, that can be surprisingly effective? I use bleach as an all-purpose stain remover. I mostly use it to clean the cream path tiles around the house which get badly stained from dead plumeria leaves and flowers. Just tip it on, scrub it in, wait 20 or 30 minutes and then scrub the stains out. Repeat as needed. Bleach isn't acidic so it won't affect the cement. 1 Link to comment Share on other sites More sharing options...
tommy dee Posted January 18, 2020 Author Share Posted January 18, 2020 6 hours ago, Freee!! said: Don't use acid, it will dissolve the concrete. i thought thast but they use h2so4 to finish the sandtone finish when they do it so thought migh be ok.. or is it hcl Link to comment Share on other sites More sharing options...
Freee!! Posted January 18, 2020 Share Posted January 18, 2020 Using sulfuric acid some of the concrete gets converted to gypsum, but superfluous acid gets rinsed of very thoroughly. Even so, I would be very careful with all kinds of acid (including vinegar) when working with concrete and cement. Link to comment Share on other sites More sharing options...
Stillearly Posted January 18, 2020 Share Posted January 18, 2020 6 hours ago, Toy Boy said: It'll depend on what caused the stains. Did you try warm water and soap yet, that can be surprisingly effective? I use bleach as an all-purpose stain remover. I mostly use it to clean the cream path tiles around the house which get badly stained from dead plumeria leaves and flowers. Just tip it on, scrub it in, wait 20 or 30 minutes and then scrub the stains out. Repeat as needed. Bleach isn't acidic so it won't affect the cement. I do similar at home , my paving stones start going green over winter ... I just put some toilet beach in a watering can with water and sprinkle over the area , it's good as new the next day 1 Link to comment Share on other sites More sharing options...
jcolorado Posted January 18, 2020 Share Posted January 18, 2020 Had several oil stains on my concrete driveway. The simple answer - kitty litter. I had major doubts but what the hell, the stuff is cheap. Poured it dry on a major area and after about 20 minutes swept it away with a broom. Voila! the stain was gone. I have also heard that you can mix a small amount of gasoline for difficult spots, but I haven't had to do so. Swear to god that it works for me. Link to comment Share on other sites More sharing options...
tommy dee Posted January 19, 2020 Author Share Posted January 19, 2020 5 hours ago, jcolorado said: Had several oil stains on my concrete driveway. The simple answer - kitty litter. I had major doubts but what the hell, the stuff is cheap. Poured it dry on a major area and after about 20 minutes swept it away with a broom. Voila! the stain was gone. I have also heard that you can mix a small amount of gasoline for difficult spots, but I haven't had to do so. Swear to god that it works for me. we used similar in worskshops but usually to absorb spills opf oil etc. this is soaked in and dried. bu thank you for the tip Link to comment Share on other sites More sharing options...
jcolorado Posted January 19, 2020 Share Posted January 19, 2020 16 hours ago, tommy dee said: we used similar in worskshops but usually to absorb spills opf oil etc. this is soaked in and dried. bu thank you for the tip My situation involved soaked in and dried oil. Had been there for several weeks if not months. You don't have to believe it. I didn't until I tried it. Link to comment Share on other sites More sharing options...
tommy dee Posted January 19, 2020 Author Share Posted January 19, 2020 in the end we tried petrol, no go, then HCl, which did the trick with the presure washer, thanks Link to comment Share on other sites More sharing options...
KhunDon Posted January 21, 2020 Share Posted January 21, 2020 Any acid used on sandwash (exposed aggregate) will definitely feck it up. If the sand and stone is quartz it won’t do much to that, but it will eat away the cement very quickly and the sand and small stones will start to fall apart. Try pressure washing it, but don’t put the Jet too close. The absorbent kitty litter or similar, is also a good idea. Good luck. 👍 1 Link to comment Share on other sites More sharing options...
tommy dee Posted January 21, 2020 Author Share Posted January 21, 2020 1 hour ago, KhunDon said: Any acid used on sandwash (exposed aggregate) will definitely feck it up. If the sand and stone is quartz it won’t do much to that, but it will eat away the cement very quickly and the sand and small stones will start to fall apart. Try pressure washing it, but don’t put the Jet too close. The absorbent kitty litter or similar, is also a good idea. Good luck. 👍 many thanks mate. it will be sealed next week too, and the truck is off to be fixed today too. all y fault i know, i ignored it. 1 Link to comment Share on other sites More sharing options...
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