Cleaning brickwork

[Andrew Gabriel]

Currently working on my chimney stack (or would be if it wasn't raining). I've just realised it's built from the same decorative red facing bricks which the front of the house is built from, except you can't tell because it's filthy. This got me to woundering how to clean it. A brush and water with washing up liquid would probably get the dirt off. However, the bricks are incrediby soft, with some surface spalling from frost damage, although given how exposed it is, I'm surprised it's not much worse after 100 years. Getting a wetting agent in them (washing up liquid) is probably going to be a disaster for their longevity, leading to more moisture penetration. So is there any special purpose or more suitable cleaner for this? Don't think I'm going to run to sand blasting.

[The Natural Philosopher]

PRESSURE WASHER.

slightly less drastic than

ANGLE GRINDER which might require

CAR BODY FILLER to repair the damage

Or HOT GLUE

There. I've got all FOUR keywords into one post, and I claim my £4000 prize...hang on..Godwins law.. I didnt work that one in..Bugger. I've missed the £10,000 bonus.

I've got it!

WHAT ARE YOU TRYING TO DO ANYWAY, TART UP AUSCHWITZ FOR A QUICK SALE?

[Frank Erskine]

Yebbut what about the Fein Multimaster? OR the WD-40?

:-)

[John Rumm]

A small hand held sand blaster might be worth thinking about - they are fairly cheap if you already have a compressor. Quite slow though since they only do a small area at a time.

[stuart noble]

A non-acidic patio cleaner? I've used them but they don't seem to differ significantly from Fairy Liquid. Slightly less foam possibly

[Bruce]

Godwin's Law applies. The discussion is terminated.

No prize payable.

(What a pity, you were doing OK until then ...!)

[The Natural Philosopher]

ou cant score on a fein multimaster.

WD-40 has been shown to be useless for almost everything, so its not ON the list.

[The Medway Handyman]

Oh yes it is!

[Bruce]

[Andy Champ]

Well he was worried about soaking the bricks. Perhaps a gallon or two of WD40 would dry them out again?

Andy

[Andrew Gabriel]

There's no cement on them, it would probably do terrible things to the lime mortar (which is in remarkably good condition), and I've no evidence the dirt is likely to be touched by an acid.

[The Natural Philosopher]

I was going to say that soot is not affected by acid too.

Alkali maybe a different matter tho. Cant remember.

I do remember that abrasives were the only thing that worked on in-laws china when we pulled it out of the burnt wreck of their house.

detergent helped a bit with the tarry stuff.

[Andrew Gabriel]

Soot probably needs a good oxydising agent, but need to avoid ones which are too explosive;-). If I go and buy a bottle of hydrogen peroxide, you'll probably see me on News at 10 in a few days time with the house surrounded by the terrorist squad...

However, it's probably not soot, or at least, not mainly soot. I think it's just general polution grime, and it's actually not at the flue outlets, so I doubt it's directly what went up the flues.

[stuart noble]

AIUI "pollution grime" is mostly soot so, in theory, washing up liquid wouldn't be the ideal detergent, it being mostly anionic and non-ionic. I think you need more of a cationic surfactant, which is probably what the patio cleaners from Bayer etc are based on. I remember all this from messing around with carbon black pigments, which are notoriously difficult to disperse. I think I'll go and get a life now.

[The Natural Philosopher]

You mean vaguely acidic?

We had a bathful, and I tried brick acid, caustic soda and detergent there separate soaks. None worked. But each did a little IIRC.

If you do know of a good soot remover, please put life to one side and tell.

[Bruce]

Sorry to change the topic but I need a small quantity of carbon black

- about a teaspoonful - and wondered if you could suggest a source?

[stuart noble]

For a teaspoonful I'd just set fire to something and have the smoke pass over tin foil or similar, where enough should collect. Being cationic, it tends to deposit itself on most surfaces. Beech soot is much prized I believe, being a brown/black as opposed to the usual blue/black derived from animal and vegetable waste. Bones and grape vines apparently produce a high quality soot for artists use if you have any lying about. If you want to get serious,

[JimK]

dead laser printer toner

[Bruce]

[NT]

or charcoal from local supmarket or garage or char something in a container in an old microwave, but good ventilation needed or black cement pigment

NT