Descale with citric acid directly

#1: Post by **Fallingwater** » March 8th, 2016, 10:00 am

I have an old espresso machine I'm trying to fix. I've cleaned up most of the exterior and head, but the boiler is caked solid with scaling and I can't get it open, because two of the four screws holding the head on are very seized - and I do mean very; they have stubbornly resisted repeated and enthusiastic applications of an impact driver. Rather than drill out the screws and have to retap the holes, I've decided to keep it together and descale it in the old way, but I'm gonna need something more powerful than the usual bland maintenance solution they sell at the supermarket.

How concentrated can I make a descaling solution? Ideally I'd just go to town with the acid and saturate the solution, but I'm worried the result might damage the insides of the machine. I should note that I don't care about any aesthetic blemishes (I basically had to break half of the casing to crack the stupid thing open already, as someone else worked on it before me and they put it together improperly), all I want is a functional pump and boiler.

#2: Post by **ira** » March 8th, 2016, 1:34 pm

I don't think you can make it to strong. Also citric acid works much faster with heat if you can figure out how to warm it up. Just below boiling seems about the best. The last really bad boiler I descaled took a few days and many changes of solution, so be patient.

Ira

#3: Post by JK » March 8th, 2016, 5:56 pm

The BEST Penetrating Oil is Kroil or Aerokroil in aerosol ..
You can buy it at Kano Labs ONLY!
http://www.kanolabs.com/penLub.html

I would wash with vinegar and baking soda after you remove screw..
I would wash this off before cracking open the boiler..

I'd also try a propane torch.. Tapping the wrench with a hammer to shock it loose..

#4: Post by **flathead1** » March 8th, 2016, 7:26 pm

Try searching the site for "Citric acid concentration." Brings up numerous discussions, a quick check seems to be 1 or 2 TBS per liter.

#5: Post by **jonr** » March 8th, 2016, 7:34 pm

Depending on the metals involved, there are stronger acids and inhibitors that will clean faster without damaging the metal.

#6: Post by **vit** » March 9th, 2016, 2:30 am

Manual of my DeLonghi machine states 30 g per half liter. I use about 20 g. Worked well so far

March 9th, 2016, 11:28 am

ira wrote:I don't think you can make it to strong. Also citric acid works much faster with heat if you can figure out how to warm it up. Just below boiling seems about the best. The last really bad boiler I descaled took a few days and many changes of solution, so be patient.

Ira

Weeell, I *am* descaling a boiler, so it shouldn't be too hard to keep it hot...

vit wrote:Manual of my DeLonghi machine states 30 g per half liter. I use about 20 g. Worked well so far

Hmm. Might try dumping a fifty-gram bag in half a litre for the first cycle and going down to 30 afterwards.

#8: Post by **ira** » March 9th, 2016, 2:05 pm

I trying to translate Italian, but it looks like the Calcinet bottle recommends 1kg per 10 liters of water.

1/2 barattolo of Calcinet in cinque litre di aqua. and later:

1kg of Calcinet disincrostante in 10 litre di aqua.

I think it's just citric acid but it might contain something else too.

Ira

March 9th, 2016, 2:48 pm

Hmm. One kg in 10 litres = 100gr in one litre = 50gr in half a litre, which is about what I'm using (the machine has the descaling solution in it as I write). Not sure if it has other things; I looked at the baggies of descaler my mom bought and they mention nothing else other than citric acid. I just went and bought acid sold for food use, which is rather cheaper despite being - so far as I can determine - exactly the same thing.

#10: Post by **ira** » March 9th, 2016, 3:48 pm

It can take take way more acid than you think. took me close to 2Kg and a few days to descale my 2 group Rancillo lever.

Ira