Descaling without damaging chrome

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
nisb
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#1: Post by nisb »

I got a good deal on an ECM synchronika that had been used in a bookshop. They seemed to have tinkered with various settings, seemingly at random.

One issue was that the pump was set to a higher pressure than the OPV clamping pressure, such that water would spill continuously into the drip tray when pulling a shot.

Seems they've had it set up like so for a long time (must have had to empty the drip tray very often), and haven't used the best water, so...



A bit hard to capture on photo but the OPV exhaust valve (behind the group exhaust valve, which is pretty disgusting as well) is pretty caked up.

How do I remove this without stripping the chrome?

Noplacetobe
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#2: Post by Noplacetobe »

Best of what I can think of is to heat the machine up and use a towel between your spanner and the chrome plate.

Marcelnl
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#3: Post by Marcelnl »

The way I read the post is that the question is how to remove scale from chrome without destroying the chrome.

After removal of the components I'd suggest cittric (or acetic) acid, the advice comes both from Paul and RPavlis:

How to descale chrome components without damage?
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BaristaBoy E61
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#4: Post by BaristaBoy E61 »

This looks like a well used old book itself but not a well adjusted or maintained machine. First priority would be to remove all scale and restore to proper functionality. Chrome parts can be replaced later and depending on results achieved.

A complete citric acid descaling would be the first order of business followed by replacement of brass valve components and seals within the group head.

Use of non-scaling water going forward would also be a priority to preserve functionality.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

JRising
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#5: Post by JRising »

nisb wrote:
How do I remove this without stripping the chrome?
On those visible parts, take it off with your thumbnail. Then when only the thinnest trace remains, use your mild acid. (Or a white plastic knife, or the edge of an expired credit card. Take it off with something hard enough to break through the calcium, but not hard enough to possibly damage the chrome (Or stainless steel, if even the drain is stainless on the "complete stainless head")).

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homeburrero
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#6: Post by homeburrero »

JRising wrote:On those visible parts, take it off with your thumbnail.
+1
Over a long time of constant drip and dry at that fitting you might expect dry residue that might be non-carbonate, may not dissolve readily in descaler. So trying to remove most or all of it mechanically first is a good idea.

Marcelnl wrote:The way I read the post is that the question is how to remove scale from chrome without destroying the chrome.
After removal of the components I'd suggest cittric (or acetic) acid, the advice comes both from Paul and RPavlis:
How to descale chrome components without damage?
Another +1. The rpavlis advice is always excellent, with a lot of chemistry expertise, and using warm white vinegar (~5% acetic acid) is a good way of assuring that the acid is not too harsh. Acetic does require a thorough flushing but is easy to flush completely away. And Paul Pratt has tons of experience at restoring tough scale-clogged vintage espresso machines.
Pat
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yakster
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#7: Post by yakster »

Nylon pan scrapers might help.
-Chris

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nisb (original poster)
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#8: Post by nisb (original poster) »

Thanks everyone!

Hadn't even thought of removing it mechanically as I assumed it would be too hard and I'd risk chipping the chrome - But makes sense that it'll be crumbly as it isn't pure CaCO3.

_Ryan_
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#9: Post by _Ryan_ »

I had minor build up and vinegar (or the adhesion and reaction to the chrome) removed chrome.
I haven't done a visual inspection since using Cafetto spectra. Vinegar was only used as a test on the mushroom.
YMMV.

Can provide before/after photos if needed to set expectations.