Newly acquired Microcimbali Liberty: had a few restore questions

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
User avatar
PacMan

#1: Post by PacMan »

Hey guys, long time reader first time poster.

I just acquired a brass Microcimbali Liberty from an individual who purchased it ~1985. I got all the original parts (both baskets/convex tamper/manuals) and the machine seems to be in decent condition for its age. I did an initial boiler descale and after two 30minute sessions there were only a few small particulates that came out so I think it's not to bad. Nevertheless I'm getting ready to pull the boiler off for a good in bucket descale. So here are two questions regarding the boiler:

1. Should I remove all the parts form the boiler (steam arm with gauge, top pressure valve / sight glass etc.) before I drop the boiler in a bucket to descale it?

2. Is it possible to remove everything form the boiler down to only the boiler itself with no other non- aluminum parts attached?

Thanks in advance for the help, I'm going to be doing a seal replacement soon so I'm sure I'll have more questions.

Tom@Steve'sEspresso

#2: Post by Tom@Steve'sEspresso »

I did a rebuild on one of these for a friend a few months ago and if I were you I would get fresh gaskets all around if you haven't done so already unless you know differently. Sure, go ahead and undo everything if you are doing a refreshening. Although I left the pressure gauge in place and just kept it out of the water by tipping the boiler sideways during descaling.

Hope your machine works well for you. My friend's machine is still a bit of a disaster.
LMWDP #222
Live graciously
Be kind
Have fun

La Marzocco · Home: customized for espresso aficionados
Sponsored by La Marzocco · Home
User avatar
PacMan (original poster)

#3: Post by PacMan (original poster) »

Thanks for the response. I'm definitely going to change all gaskets. I'm starting to slowly take everything apart according to the Orphan Espresso guide. So far it looks like my machine was lacking a group gasket and the little black disk under the dispersion screen. Also, it looks like the cylinder is nicely attached to the boiler so I'll have to knock it out from the top once I get the piston assembly off.

Speaking of the piston assembly, all I have to do is remove the cap nuts on top and the whole thing should lift out right? My piston assembly doesn't want to budge. Any suggestions?

User avatar
PacMan (original poster)

#4: Post by PacMan (original poster) »

Well, that didn't last long...

I got everything apart after a good one to two hours of descaling. Took the piston assembly out and was happy to see minimal scale or damage to the spring or piston rod. Decided to next knock out the cylinder from above which was rather uneventful. The cylinder was also in great shape. Then when I looked back at the boiler I realized that it was a goner. The lip on the boiler that holds the cylinder to boiler oring was completely scaled and deteriorated. 75% of the lip is completely gone. So basically, no way to attach the cylinder to the boiler anymore. It was great while it lasted but now I have a nice collection of parts and no boiler. I think I'll start searching for a new lever machine to restore that doesn't have an aluminum boiler :?

User avatar
orphanespresso

#5: Post by orphanespresso »

Sorry to hear about the corrosion. That lip spot is trouble on the machine. It might have held together for a while without the descaling but the lack of metal is a problem. You have well illustrated the problem with the cast aluminum boiler machines and it seems more or less unsolvable. An intact boiler in good shape that has been chrome plated may be the only solution in the long run....if you want it to last.
It is my opinion that the function of the little faucet at the bottom of the machine boiler is not to use as a hot water source but as a way to fully empty the water from the machine after each use to prevent scale buildup from water sitting in the machine.

User avatar
drgary
Team HB

#6: Post by drgary »

orphanespresso wrote:You have well illustrated the problem with the cast aluminum boiler machines and it seems more or less unsolvable. An intact boiler in good shape that has been chrome plated may be the only solution in the long run....if you want it to last.
Hi Doug,

With regard to the Lady Duchessa you just restored for me, which has a cast aluminum boiler in good shape, is this a consideration? The boiler on the Duchessa is very thick. What needs to be watched to make sure such a corrosion breakdown doesn't happen? Or on machines like this, should they be emptied after use or have other measures taken short of plating to avoid corrosion?

Later add:

Quick link to summing up Microcimbali

For those wanting to see pros and cons of a Microcimbali (older version of Liberty but very similar with lots of interchangeable parts), you can cut to the chase here, where I summarize those after successfully restoring my machine (ignore label on the link, it will take you there): Newly acquired Microcimbali Liberty: had a few restore questions
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

User avatar
orphanespresso

#7: Post by orphanespresso »

The Duchess was pretty pristine inside. Possibly a different alloy but definitely a better design...just a smooth vessel inside without a lot of fancy cast ridges and forms plus very thick. She is made in such a way that the boiler can be dumped and she can be stood on her head on a towel and get really dry. No matter what you do the Micro always seems to maintain some water around the edges.

Weber Workshops: tools for building better coffee
Sponsored by Weber Workshops
Warrior372

#8: Post by Warrior372 »

Is this a problem with older Microcimbali's too? Have they always made the boiler out of aluminum? Is the only way around this to not introduce low / acidic pH cleaning solutions to the aluminum? I have never restored a machine with an aluminum boiler, but I am guessing a low pH would breakdown the layer of aluminum oxide that formed when water met the aluminum. Would you just use a copper wire brush to descale the boiler and forgo the acidic descaling solution?

Added later:
I would think chrome plating a boiler would predispose it to a similar fate. When chromium is exposed to water it turns into chromium oxide, which protects the underlying surface similarly to how the aluminum oxide layer protects the aluminum.

User avatar
Bushrod

#9: Post by Bushrod »

If you got it in VA, listed on Craigslist, then at least you didn't pay a lot!
Rich A

LMWDP #131

User avatar
Carneiro

#10: Post by Carneiro »

Oh boy, I have a Microcimbali (1984) to replace seals and I'm already scared about the corrosion... After a lot of pain with the Peppina I was not wanting this kind of challenge again!

Márcio.