Hi, I have just had some lead flashing fitted for a new roof and in the process the lime mortar was cut out of a mortar joint to fit the sheeting. Problem is the dust from the cutting process was not extracted properly by the contractor and has gone all over my nice 1863 red kent bricks (not impressed - looks very bad). I've tried brushing off, washing with water, but to no success. Any ideas how to remove this white bloom all over my bricks without damaging them or anything else??
Thanks.
Lime, once set, is just chalk (mixed with sand usually), so it's just chalk dust. A soft brush attachment on a vacuum cleaner might have been a good way, but I suspect it's got washed into the brick faces by now. Brick acid will dissolve it and shouldn't harm brick faces, but it will also dissolve the lime mortar. You might be able to get away with spraying on a thin dilute layer which is just enough to wet but not run down the bricks. This would dissolve all the chalk on the brick faces but a negligable amount of the pointing, and can then be washed away with water. As always, try it on a small area first, and leave it for a day or more to completely dry after washing so you can see if it has caused any effect on the brickwork. Also, spraying acid is potentially very dangerous from risk of inhaling and drift, both of which you need to protect against.
brick acid and a hose.
thanks to both - will try out
I doubt acid will do anything much to chalk, other than make it fizz and leave you with calcium something or another, which might be even more difficult to get rid of.
The whole point is that it turns calcium carbonate, insoluble, to calcium chloride, soluble.
Its made, sold and used for PRECISELY this purpose - to make insoluble calcium salts soluble.
But in this case the calcium isn't bonded to the bricks, and would wash off it hadn't penetrated the pores. Making it water soluble might drive it further in.
never mind the fact that this method has been used for many a year! However I'm told it can damage bricks, leading to slow disintegration, so would be wary of doing this.
Hoovering may remove at least some, brushing some more, but I wouldnt expect that to clear it.
NT
But that doesn't matter, because it will wash out again when it rains.
Why a I bothering? I know it works, you don't. Piss off. Life's to short.
Total bollocks. If the acid has any reaction at all its with the mortar. once its reacted, its finished. What's left washes away as various soluble chlorides.
No, acid and pressure washing does, or just acid and let the rain do its work.
Not much of a philosophy is it?
Ohh, Get you.
In this case I think it is entirely rational.
Someone asks a question, the answer to which I happen to know, because I have actually a little knowledge of chemistry, and have had to face exactly the same problem my self and have solved it satisfactorily..
someone else who obviously has never tried the solution or, indeed had the problem, comes along spouting contrary hearsay and pseudo science.
The OP has vanished, presumably having taken some advice.
I am left arguing with a tosser.
What to do? Patiently explain the principles, the practical results obtained?
And then have the tosser comes back and says 'I don't believe you: My mate says you are talking bollocks'
At that point one realizes that a rational discussion is no longer possible, and whilst it is possible to insist, it is not possible to dislodge ignorance and prejudice by the mere use of a keyboard, when faced with those whose purpose is not to learn or to reason, but to bolster their own egos by the apparent winning of a pissing match.
Since my actual purpose in being in this thread was to assist someone with the benefit of my experience and knowledge, and not act as a prop to the lack of self esteem of someone whose boredom and lack of knowledge leads them to be an armchair expert on everything they don't actually understand, I have no further purpose in continuing the thread, and an honest exit kine seemed to be the easiest way to save time.
I.e. since that individuals purpose seems to be to develop skills as a prime wanker, I feel that in that area his experience entirely outweighs mine, and there is nothing more to be said.
A somewhat hysterical reaction. If you can't bear to have your advice questioned in any way, maybe newsgroups are not for you.
I don't mind having it questioned by someone who is genuinely querying it for a valid reason.
If you think that was a hysterical reaction, and you further think that Usenet is not a place where hysterical reactions are common, then I suggest Usenet is not for you.
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