# stubborn limescale



## rich987 (Feb 5, 2018)

I have bought a used La Pavoni and it needed a good descale.

After trying a sachet of oust (20 mins) and then some vinegar (overnight), most of the scale is gone, however there are still areas of stubborn scale left.

These don't appears to fizz when putting vinegar in.

The element is now clean, so not sure if I need to worry about what's left?

Is it worth trying some citric acid next?


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## El carajillo (Mar 16, 2013)

It is not worth bothering with vinegar, it is not aggressive enough. Go with citric acid or Calcinet.


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## urbanbumpkin (Jan 30, 2013)

Citric acid


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## espressotechno (Apr 11, 2011)

Calcinet, in hot water, is better.


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## rich987 (Feb 5, 2018)

Cheers peeps!


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## ajohn (Sep 23, 2017)

I read a comment in one make of espresso machine's manual not to use sulphamic acid as it''s 6 times stronger than citric. The not use it seems odd as it is in some descalers - Sage's for instance. Puly don't mention what is in theirs but may well contain it.

Sulphamic acid is used because it's a safe substitute for hydrochloric acid. Sulphamic acid crystals are easy to buy. Cement cleaner is a weak solution of hydrochloric acid. I'd guess what can be used depends on the materials that are in the machine and what the acids do to them. The machine I noticed has stainless boilers and seemed to be saying citric acid only but that this might be inadequate if scale had actually built up.

John

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## ashcroc (Oct 28, 2016)

ajohn said:


> I read a comment in one make of espresso machine's manual not to use sulphamic acid as it''s 6 times stronger than citric. The not use it seems odd as it is in some descalers - Sage's for instance. Puly don't mention what is in theirs but may well contain it.
> 
> Sulphamic acid is used because it's a safe substitute for hydrochloric acid. Sulphamic acid crystals are easy to buy. Cement cleaner is a weak solution of hydrochloric acid. I'd guess what can be used depends on the materials that are in the machine and what the acids do to them. The machine I noticed has stainless boilers and seemed to be saying citric acid only but that this might be inadequate if scale had actually built up.
> 
> ...


The (now discontinued) gaggia descaler powder was tartaric acid so I just got more of that when I ran out. Can't remember why I didn't just go for citric acid but it works so I'm happy.


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## Zeak (Jun 12, 2017)

Had the same issue with Gaggia's boiler. Used tons of the descaler. Soaked it for hours but still had some stubborn leftover scale in the corners. It wouldn't even scrub away mechanically so I had to just leave it there..


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## yusuf7869 (Jan 26, 2018)

I am in the same boat, the best results i got for my gaggia boiler


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## MildredM (Feb 13, 2017)

If you need a good line scale remover to brush on smaller parts then I can recommend Kilrock Gel.


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## ajohn (Sep 23, 2017)

I think this stuff is intended to be used when machines are stripped down - that method seems to be what is recommended on commercial machines to prevent bits of scale from clogging something up. A so called professional descale.

https://www.happydonkey.co.uk/machine-cleaning/commercial-coffee-machine-descaler/

There are some pictures of scale on that site - black scale doesn't make much sense to me.

It might just be sulfamic acid or more off it with the usual stuff.

John

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## DavecUK (Aug 6, 2013)

I reckon we need Barry Scott to help with this problem

http://www.oxygen.ie/cillit-bangs-barry-scott-found-dead/


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## Missy (Mar 9, 2016)

ajohn said:


> I think this stuff is intended to be used when machines are stripped down - that method seems to be what is recommended on commercial machines to prevent bits of scale from clogging something up. A so called professional descale.
> 
> https://www.happydonkey.co.uk/machine-cleaning/commercial-coffee-machine-descaler/
> 
> ...


I've got a tub of it on the way.. wish me luck!


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## MildredM (Feb 13, 2017)

DavecUK said:


> I reckon we need Barry Scott to help with this problem
> 
> http://www.oxygen.ie/cillit-bangs-barry-scott-found-dead/


That's bang out of order


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## DavecUK (Aug 6, 2013)

MildredM said:


> That's bang out of order


"BANG!" and Barry is gone..


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## espressotechno (Apr 11, 2011)

heavy duty v. light duty: Just depends on the dilution ratio....


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## ajohn (Sep 23, 2017)

Missy said:


> I've got a tub of it on the way.. wish me luck!


It will be interesting to here how you get on with it. There are some instruction here - in case you didn't notice them

https://www.happydonkey.co.uk/hd0401-calcinet-coffee-machine-descaler.html

John

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## ajohn (Sep 23, 2017)

yusuf7869 said:


> I am in the same boat, the best results i got for my gaggia boiler
> 
> 
> 
> ...


Is that an aluminium boiler ? Aluminium is odd stuff in some respects. It resists corrosion because it corrodes very very quickly and gets a coat of aluminium oxide which does resist further corrosion and prevents it going further.

John

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## ajohn (Sep 23, 2017)

ajohn said:


> Is that an aluminium boiler ? Aluminium is odd stuff in some respects. It resists corrosion because it corrodes very very quickly and gets a coat of aluminium oxide which does resist further corrosion and prevents it going further.
> 
> John
> 
> -


As no one answered - A bit of caution if it is aluminium. Some acids might remove the aluminium oxide and then the aluminium will corrode. The result might well be black.

John

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## ashcroc (Oct 28, 2016)

ajohn said:


> As no one answered - A bit of caution if it is aluminium. Some acids might remove the aluminium oxide and then the aluminium will corrode. The result might well be black.
> 
> John
> 
> -


It is aluminium. I personally wouldn't use anything stronger than citric or tartaric acid on it even if it does take an age.


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## ajohn (Sep 23, 2017)

With aluminium it would be best to try some on aluminium and see what happens. Eventual bubbling would be bad news. Maybe some area of the boiler would be the best place to try it. Aluminium drink cans may be coated with a plastic as tin cans have been for a long long time. There are also many grades of aluminium.

I had a look around on the web but not much came up. One link suggested that sulphamic acid by another of it's names was wonderful on aluminium. Another where it was being sold for descaling said aluminium with care and mentioned brush it on an scrub it off on other materials. Brick cleaner would be a no no as that will dissolve aluminium oxide eventually on the other hand it might dissolve scale very quickly.

John

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