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Posted: Wed Jul 01, 2009 7:31 pm
by James27
Hi
I recently laid an indian sandstone patio however got some cement stains that dried on. Its only on a few slabs but it really spoils the looks. I was wondering if i could use sandpaper to clean the cement stains off? I couldnt find any info on the stains page about using sandpaper i wondered if it might be better than a wire brush?
Posted: Thu Jul 02, 2009 9:11 pm
by James27
anyone know?
Posted: Thu Jul 02, 2009 9:46 pm
by lutonlagerlout
never seen it done,try an out of the way patch first
brick acid can do alll sorts of weird stuff to stone so dont go there
who got stains on the flags in the first place?
LLL
Posted: Fri Jul 03, 2009 12:28 pm
by James27
It was me that got the stains unfortunately, tried my best to keep them off but got a few on there 
thought sandpaper might be less likely to scratch the stone than a chisel or wire brush
Posted: Fri Jul 03, 2009 2:53 pm
by worldofpaving
As a bit of PR, this company might be prepared to send a small quantity of their molecular cement dissolver over : go to
wwwdotromixchemdotcom
Tell them you'll post a review here on the pavingexpert forum.
You never know, perhaps they'll want a stand at Worlof Paving!
Best,
WOP
Posted: Fri Jul 03, 2009 4:10 pm
by James27
Thats an interesting idea actually, i'll drop them a line, cant hurt to try and if the stuff truelly works then i'll be able to let the good people on here know about it! And if it doesnt work then back to my sandpaper i guess!
Posted: Sat Jul 04, 2009 10:47 am
by Rich H
It's acid-based. May well screw your paving forever. Also incredibly expensive!
Have you tried a pressure-washer? Can be effective on 'fresh' cement stains.
Posted: Sun Jul 05, 2009 8:56 am
by RAPressureWashing
As stated be very careful with any acid on your sandstone.
Pressure washing can and does in some cases remove concrete staining/snots etc, you just really need to be careful that you don't mark or etch the surface, we would not pressure wash any paving for at least 6 weeks if the pointing has been done, IE give it time to cure properly.
Posted: Sun Jul 05, 2009 10:54 am
by colordrives
use a decent pressure washer but ensure you protect the joints from being sprayed directly.
Posted: Sun Jul 05, 2009 12:15 pm
by worldofpaving
Rich, the manufacturer describes the product as "an acid alternative" and whilst these are hard times, if you were buying it, is £2.73 for a litre "incredibly expensive"?
Clearly you would test it, or anything else, on an off cut before applying it to the sandstone as the manufacturer advises on the website.
Be interesting to see if it works in this sort of application.
Best,
WOP
Posted: Sun Jul 05, 2009 12:45 pm
by Rich H
I read it as an acid alternative, not an alternative to acid. It states that the detergent contains citric acid, so I think that bears it out.
I didn't dig deep enough to see £2.73/litre which seems like really good value, I was just seeing $500 for the batch on offer. Can you provide a link for the product in lower volumes?
Posted: Sun Jul 05, 2009 12:58 pm
by msh paving
Last year at SED i was watchin a demo on the belle mixer stand for a product to clean mixers with no acid,it was £10 for a squirty bottle i bought one,it cleaned all my levels and tools great,no acid at all, might be worth a call to belle mixers to see if they still can get or speedcrete concrete sold a similar product there web is www.speedcrete.co.uk MSH 
Posted: Sun Jul 05, 2009 8:14 pm
by James27
have dropped the guys a line at romixchem.com no answer from them as yet! not going to hold my breath yet! Regarding the acid ingredient i'm not sure whether it is acid or acid based, if it has citric acid in thats from fruit and i read somewhere on this site that lemon juice could be effective for cleaning cement stains. (although you might need a lot of it!) Am going to try power washing it in a few weeks, just pointed last week so will need to wait for that to cure i guess.
Posted: Sun Jul 05, 2009 8:39 pm
by RAPressureWashing
James27 wrote:have dropped the guys a line at romixchem.com no answer from them as yet! not going to hold my breath yet! Regarding the acid ingredient i'm not sure whether it is acid or acid based, if it has citric acid in thats from fruit and i read somewhere on this site that lemon juice could be effective for cleaning cement stains. (although you might need a lot of it!) Am going to try power washing it in a few weeks, just pointed last week so will need to wait for that to cure i guess.
I would wait for at least 6 weeks before pressure washing.
With regards to getting samples esp chemicals sent over from the USA, we have never had any luck, due to some be classed as hazardous etc so it becomes a pain for everyone involved.
Posted: Sun Jul 05, 2009 9:06 pm
by James27
Yeah thats true, i'll let you guys know if i head anything back from em. Otherwise its the pressure washer and some good scraping with the wire brush. If the wire brush scratched the paving i assume the scratches would just weather away? Also anyone have a good idea for how i can stop the joints from being sprayed out? Do i just have to go very careful or could i cover them with something?