Cleaning stains on glass!

[mgraham]

New to this forum and completely inexperienced in Chemistry! Just desperately need some sound advice!

 

I have double-glazed windows with leaded lights (type where lead strips are applied to surface of glass).

 

Over time, dreadful white staining has come from the lead and run down the glass... My internet research leads me to believe this could be calcium carbonate staining... but I stand to be corrected!

 

I've tried all manner of household cleaners on this, plus other receommendations of vinegar, lemon juice and elbow-grease, etc - No luck.

 

Is is likely that this is calcium carbonate staining and if so what chemical/method could be used to remove it without damaging the glass... and if so preferably somehting the "man in the street" could easily obtain to do the job?

 

Hope someone can advise!

 

Thanks.

[hermanntrude]

I'd guess it could be lead oxide or sulfide or something. I could be wrong too.

[StringJunky]

When new lead is exposed to the weather it goes through several stages of oxidation. This process is called patination. I found this:

 

" When lead comes into contact with moisture, rainwater, condensation etc., at early stage, discoloration, spotting and white powdery deposits (usually basic lead carbonate) can form and may ‘run-off’. The degree to which all these occur is governed by the environmental conditions, but with longer term weathering, the lead will take on its’ familiar appearance.

 

Investigations have shown that the patina formation follows the route: lead, lead oxide, basic lead carbonate, normal lead sulphite, and normal lead sulphate. The ‘run-off’ stage occurs when non-adherent basic lead carbonate is formed, usually through contact with moisture. Each of the stages in patina formation is adherent, highly insoluble lead salts and in practice, as these salts develop with weathering, they stifle the basic lead carbonate release. The final patina being approximately 30% normal lead sulphite, 60% normal lead sulphate and 10% normal lead carbonate. However, this can vary dependant upon location, time and airborne impurities.

 

Suggested after care

 

In the event that you experience an accelerated rate of oxidation directly after installation, you should make every effort to clean the ‘run-off’ deposits, as soon as possible. Failure to do so could result in the deposits drying onto the glass and becoming more difficult to clean. This effect can be compared to lime scale on a shower screen.

 

To clean the glass, simply use a water-based glass cleaner with a paper or cloth towel, whilst removing any stubborn stains with a household non-abrasive cream cleaner. Avoid agitating the surface of the lead, as much as possible, as this will slow down the weathering process."

 

It looks like you've left the deposits long enough to develop to the more resistant lead compounds beyond basic lead carbonate

 

Maybe one of the chemistry experts can help you now they know what they are dealing with.

[mgraham]

stringJunky - The text you've found EXACTLY describes the problem... So it looks like lead compounds on the glass, beyond the basic compounds?

 

It's very well dried on (over several years) and normal cleaners do not work at all.

 

So, has anyone any ideas on how to shift it!!!

[StringJunky]

I've tried to find a chemical solution but it's beyond me..my chemistry is too limited and I don't know what to look for.

 

If you don't get any positive feedback, I suggest you get some Jewellers Rouge which is an extremely fine abrasive paste/powder for polishing gemstones...it can remove scratches from glass without marks when used properly, so it should shift your stains quite easily. . Google: 'Jewelers Rouge: to check it out.

[hermanntrude]

the only thing I know for sure that lead carbonate is soluble in is nitric acid. I doubt you want to clean windows with that, though :0(

[StringJunky]

Hermanntrude: I had a hunch there wasn't any safe chemicals to remove these compounds because they are highly stable and resistant to reaction once the process of patination is complete...that's why lead is used for these sorts of purposes isn't it?

 

I think mechanical removal is probably the ony solution, hence, my suggestion of Jewellers Rouge which is the finest of the abrasives that I'm aware of. My Grandad used to polish out the scratches in my watchglass with it when I was a boy.

 

Jewellers Rouge is Iron (111) Oxide and is used to put the final polish on gemstones and lenses...one doesn't need any finer than that!

[hermanntrude]

sometimes a paste helps. Perhaps a mixture of vinegar and flour... you could smear it on, leave it for a while and then scrape it off. I've heard of people cleaning copper and silver this way

[StringJunky]

Your right, but you missed out the salt!:

 

This is from a site called TipKing:

 

" Dissolve 1 teaspoon salt in 1 cup white vinegar. the add enough flour to make a paste. Use the paste as you would any commercial cleaner. Rinse clean and buff to a shine with a soft cloth. "

[hermanntrude]

not sure if the salt makes a lot of difference

[Mr Skeptic]

I hear stained glass windows are more valuable anyways:D:-p

 

Um, apparently strong bases such as sodium hydroxide can dissolve lead oxide. I don't know if they would have any effect on other compounds of lead.

[jdurg]

Strong bases may also harm the glass as well, so I would avoid them.

[Justonium]

I suggest hydrochloric acid (lots of toilet cleaners have it). Just wear gloves, keep the room ventilated, and don't spill it on anything organic. I use it to dissolve all kinds of metal oxide or carbonate stains on my glassware.

[exaxol]

Strong bases may also harm the glass as well, so I would avoid them.

 

yes, but only after prolonged exposure. base on glass for about 5-10 minutes hardly affects it...depending on the strength of the base (pKb). Just rinse off with TAP water, not DI, as tap rinsed base off much faster. THEN, if you need to, you can final rinse with DI.

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I suggest hydrochloric acid (lots of toilet cleaners have it). Just wear gloves, keep the room ventilated, and don't spill it on anything organic. I use it to dissolve all kinds of metal oxide or carbonate stains on my glassware.

 

Of course, HCl is also available as Muriatic in hardware stores. It is very strong, however, so be careful. Typical Muriatic is about 10 Molar (also 10 Normal), or about 80% of full concentrate.

[John Cuthber]

Lead acetate is a lot more soluble in water than lead chloride is.

If you are cleaning the tarnish off copper then adding salt seems to help- I guess it's some sort of complex formation.

I don't think it would help with lead.

[mgraham]

Thanks to everyone for their advice.

 

So far, I've tried the cleaning with a paste of flour & vinegar - Left to dry and then cleaned off. This hasn't touched the lead staining at all.

 

Will try and obtain the hydrochloric acid - I believe that's sold as Spirits of Salts here in the UK?

 

Will let you know progress!

[StringJunky]

Remember not to touch or rub the leading with anything, because if you do the exposed shiny parts will produce the basic lead carbonate deposits again that started the stains (run off) in the first place.

[THX-1138]

Will try and obtain the hydrochloric acid - I believe that's sold as Spirits of Salts here in the UK?

 

Yes. In addition to looking for it under 'spirits of salts' and 'muriatic acid,' you can probably find it at any store that sells swimming-pool maintenance supplies.

[compfet]

As mrgraham never came back to this I thought I would let everyone know HCL does work.

 

I have this problem and google finally brought me to this thread. I just happened to have some Concentrated Hydrochloric Acid from about 30 years ago so gave it a try and it has remove virtually all of it, just a light ghost is left.

 

Method used

NOTE: You need protection - e.g. gloves, mask (there will be fumes), old clothing

I used an old cloth to apply the acid.

Apply a dab of acid to the cloth.

Coat the glass squares with the acid (best to avoid the leads as it will clean them and probably make the issue re-occur)

Leave on for a few seconds

Rub square with dabbed acid cloth.

Clean off acid with plenty of water.

Dry with a clean cloth.

[JohnnyC]

My conservatory glass roof has lead staining from the lead flashing immediately above. I have tried many cleaning products and managed to remove some of it with Ciff kitchen cleaner.

A friend then suggested Cillit Bang. I couldn't believe after leaving it on the stain for just 5 minutes the stains just disappeared. I can't promise it doesn't also remove the self-cleaning layer on my glass but to see the stain disappear is amazing.

I am truly impressed but anyone trying this product should proceed carefully and maybe try it on an area that doesn't show. For me it is a final answer to this problem but you must use it in accordance with the manufacturer's instructions and wear appropriate protective eye wear and gloves.

 

[shiny UK]

Hi,

 

someone mentioned that cillit bang can be used to remove lead stains from glass.

May i ask which of the different products have been used?

Thanks for the answer

 

[jrk1]

Johnny C Can you say which Cillit Bang was so successfull please; there appear to be several variants of Cillit Bang

[Deborah.]

Hi

 

I have the same problem as all you guys, I've tried everything but today I made a discovery!!! On a whim I tried Hob Brite. It's absolutely fantastic! I put a small amount on a dry piece of kitchen roll and wiped my window. All staining came off immediately with no scrubbing at all and then wiped it over with a clean dry piece of kitchen roll to remove smears.

 

Buy this in any supermarket.... HOB BRITE by homecare. Try it and let me know what you think! 😃