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Thread: Trying to clean an old gaggia

  1. #1
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    Trying to clean an old gaggia

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I've sourced a cheap used Gaggia, which I'm trying to clean up for a friend. I'm used to rebuilding proper machines with proper boilers, but this Gaggia has a boiler in bad shape, and I'm not sure if it's worth keeping.

    IMG_20181126_162329.jpg IMG_20181123_110415.jpg

    I've seen some mention that one can use white vinegar, but the vinegar bottle explicitly states not to use on aluminium. I've tried citric acid in various concentrations, but it doesn't seems to come out clean enough.

    Is this boiler past it?

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    Quote Originally Posted by iampivot View Post
    I've sourced a cheap used Gaggia, which I'm trying to clean up for a friend. I'm used to rebuilding proper machines with proper boilers, but this Gaggia has a boiler in bad shape, and I'm not sure if it's worth keeping.

    I've seen some mention that one can use white vinegar, but the vinegar bottle explicitly states not to use on aluminium. I've tried citric acid in various concentrations, but it doesn't seems to come out clean enough.

    Is this boiler past it?
    WLL seem to use standard descaler (though Gaggia branded)

    https://youtu.be/N9i-EH7qXOc

  3. #3
    Senior Member Lyrebird's Avatar
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    With that level of scale the citrate will saturate quite quickly so you need to change it frequently. The warning of not to use acetic acid on aluminium is because it will etch the surface causing permanent staining, you are long past caring about that.

    I'd make up a decent sized batch of DIYscale (tm) : dissolve 500 g of citric acid in 10 litres cold water, add 2 litres cheap supermarket vinegar. Place part in bucket, add as much solution as required to cover. After a couple of hours, brush vigorously then tip out solution and replace. Repeat until solution is exhausted or part clean.

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    500g? Where do you get those quantities?

    So the black aluminium staining is not a concern, food safety wise?

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    Senior Member CafeLotta's Avatar
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    I think I'd pay the $89 + postage and replace the boiler - https://www.jetblackespresso.com.au/...lassic-boiler/

    Aluminium isn't the greatest thing to use for preparing consumables (food or drink) at the best of times but using one in that state, even after a clean-up........
    Last edited by CafeLotta; 28th November 2018 at 04:16 PM. Reason: Added comment.

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    Senior Member Lyrebird's Avatar
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    Quote Originally Posted by iampivot View Post
    500g? Where do you get those quantities?
    I buy it in 25 kg sacks from a chemical supply company* but it will be easier for you to go to your local home brew shop. One near me charges $12.50 per kg.




    * Citric is the standard rinse agent used in wineries after cleaning stainless tanks and equipment with caustic, it reforms the oxide layer and prevents sulphide carryover. I'm a bit fanatical about cleaning so I use a lot of citric.

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    Ok, thx. Isn't it faster to use hot water as well, or is that too much for the aluminium? I usually use hot water when I do a copper boiler.

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    Senior Member Lyrebird's Avatar
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    I prefer cold water. Some calcium compounds are less soluble in hot water than cold..

    Heat will however accelerate other reactions you don't want such as the dezincification of brass.

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    Dremel tool is the go to solution when the GAGGIA aluminium boiler is scaled up that badly.

  10. #10
    Senior Member CafeLotta's Avatar
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    Missed the fact that Coolie21 had already posted this link in Post #2. Apologies for the plagiarism.
    Last edited by CafeLotta; 28th November 2018 at 08:54 PM. Reason: Unintended Plagiarism

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    Quote Originally Posted by CafeLotta View Post
    Might be worth a look. 34min long and these guys usually have something useful to say.

    How To Clean and Rebuild a Gaggia Aluminum Boiler - https://www.youtube.com/watch?v=N9i-EH7qXOc

    Agreed. That's why I posted the same link in the first reply to the OP
    CafeLotta likes this.

  12. #12
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    Another link that might be helpful. No videos just pictures and instructions. Gaggia Classic Disassembly and Cleaning | [protofusion]

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    This is what the two boilers look like now, with a bit of help of the Dremel. Are they really food safe in this condition, or are new boilers required?

    IMG_20190106_134229.jpg

  14. #14
    Senior Member LeroyC's Avatar
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    Quote Originally Posted by iampivot View Post
    This is what the two boilers look like now, with a bit of help of the Dremel. Are they really food safe in this condition, or are new boilers required?

    IMG_20190106_134229.jpg
    You canít use them like that as you wonít get a seal. The one on the left looks slightly better and could possibly be used, but youíll need to grind the face down so that itís flat. Are they food safe? Who knows really. As safe as Alu ever is I guess.

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    Senior Member deegee's Avatar
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    Get a sheet or two each of fine medium and coarse emery paper, and sand the bottom until it is smooth and flat where it contacts the gasket.
    I find the best way is to pin or clamp the sheets to a flat smooth surface such as plywood or masonite then rub the bottom of the boiler against the emery to sand it off. To keep the new surface square, you can use a figure 8 motion, or just push it to and fro, rotating the boiler 90į every "X" number of strokes. It's not critical, but you don't want to end up with a nice smooth flat surface that's way off parallel with the original.

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    So the boiler is food safe in this condition, if fed only filtered water? Otherwise will use the machine for parts.

    I will try with some emery paper, assume medium would be about 600, coarse 400?

  17. #17
    Senior Member deegee's Avatar
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    With emery that fine you would have to use a LOT of elbow grease to remove enough metal to get past the pitting.
    For this job P80 will be coarse enough for fairly fast sanding to get past the pitting, and P180 will give a smooth enough surface for the gasket to seal against.

    I have never used filtered water in any of my machines, but I descale regularly. and will strip, clean and rebuild when necessary.

    As for "food safe" - it certainly doesn't bother me, but you will have to make up your own mind about that.



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