Where can I buy some dilute acetic acid from?
I've bought some Peelaway from the internet to remove paint from plaster mouldings, it's made of Sodium Hydroxide, an alkali and it says i need dilute acetic acid to wash down afterwards. The kit even includes Litmus paper to check its been neutralised!
I think its vinegar but that would stain the plasterwork wouldnt it?
Clear vinegar? Look for non brewed condiment on the bottle. Probably the cheapest one on sale in the supermarket.
White vinegar is basically acetic acid and water. You can use it to neutralise the sodium hydroxide. Depending on its concentration, it can be quite agressive, so take suitable care.
Do not use malt vinegar - it also contains acetic acid but will smell and stain.
FWIW, the modern chemical name for acetic acid is ethanoic acid.
I should have added that you can get it (white vinegar) from any any supermarket.
Is it oil based paint you're removing? Alkali strippers won't touch emulsion.
Would it be the "non brewed condiment" stuff?
Owain
No sure. I found an old bottle which says "The Original Cross & Blackwell Sarson's Vinegar Distilled Malt". The label also says 'traditionally brewed" so mine can't be the"non brewed" kind! I don't think it really matters though - if its the colourless, clear type (looks like water) it should be fine.
It still smells vinegary though. I'd be tempted to test it (diluted to the concetration needed) on something that can be left outside to make sure the smell clears when the acid dries out. Good ventilation if used indoors would be important. If the OP reads this, he might want to bear it in mind.
Steve
Any acid will do. Citric acid (from winemakes suppliers) or even well diluted brick acid (hydrochloric acid)
Malcolm
Bloody hell. I'm not putting that on my chips..
Why did they change it then? And who said they could? :-)
The free stuff on the counter at the chippy is invariably non-brewed.
I would think twice before getting caustic soda anywhere near plaster as it penetrates mercilessly and is then impossible to get rid of. Neutralising it with acetic gives you salts that are almost as troublesome as the original
pre 1970, IIRC. You should see what they call citric acid.
Don't worry - it's well diluted with dihydrogen monoxide.
If it's vinegar, it's brewed alcohol that's been oxidised (usually from beer if it's malt, or any kind of distilled alcohol if it's spirit). If it's non-brewed condiment it's food-grade industrial acid (probably from oil) that's been watered down.
Either should be fine. It will smell vinegary by definition (the smell is the acid evaporating, so you can't avoid it).
Theo
i think its emulsion which someone smothered the moulding with.. so the peelaway might not work... [g]
It may break up the emulsion because of the prolonged soaking, but won't dissolve it. I'd test a (very) small area first
emulsion forms a very thin film, so is less troublesome re bulk. If there's bulk there and its not oil paint, its likely to be distemper. That's lime based and removes with acid.
A good way to get acetic and other things most chemists dont stock is to look for a chemist's thats been there for decades and ask, explaining what you'll do with it. Reasonable chance they'll still have some things in stock from decades ago, and a person that would be happy to sell such things, once they know you know how to handle the stuff.
NT
Phew, thanks heavens for that. Hang on a minute! Isn't that lethal?
Nitromors shifts emulsion, use it all the time to get emulsion paint off copper pipes.
Well, the water companies are doing their best to eliminate it from the pipes before it reaches us, so there must be something wrong with it. If it were saleable they'd charge us for it.
White Vinegar is the acetic acid I need, thanks, I will try a big supermarket for it tomorrow, its used for trendy green organic cleaning, plus rubber gloves etc.
But someone here said alkali strippers wont touch emulsion. There are thick layers of emulsion on the mouldings, it took me an hour to clear up a foot of it with plastic scraper water and toothbrush.
Peelaway1 label says it will remove any combination of household paints and varnishes containing oil, lead, polyurethane or water so i'm hoping it will work.
I will apply a thin layer on a test patch out of view, and then cover it with the gauze and try and peel it off after an hour or two.
here's a photo of it
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