Newly acquired Microcimbali Liberty: had a few restore questions - Page 6

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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drgary
Team HB

#51: Post by drgary »

Got the lever cap tonight from PacMan. Thank you Duy! He warned me before sending it, it was very scaled. He sent a photo and offered it at a righteous price. After 15 minutes with a pick tool and wire brush I was able to clean it pretty well and remove the baked seals.



The outside, though, looks like it may be powder coated or painted. I don't think that's garden variety crud.



Just to test that notion I've plunked it into a regular strength Dezcal bath overnight. There were no spots that looked like they were badly pitted. If it is powder coat I may need to heat and/or polish it to get that stuff off and match my machine.



There's something poignant here about his starting the thread, his machine going under, my entering the thread to start my restoration and then using some parts from his MC, R.I.P., including the portafilter and baskets that I'll use as spares. It kind of unifies this thread.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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drgary
Team HB

#52: Post by drgary »

The new cap is now installed on the machine and it works but needs some new seals, which I'm ordering.



For educational purposes, I'd like to follow up on a suggestion by Ray Johns. He says that JB Weld may be able to fix a cracked part. Here's the old part from the top,



from the bottom, so you can see it isn't split off and doesn't go all the way through,



and from the edge, so you can see the amount of warping in the piece.



Is such a part a candidate for JB Weld? Would it need to be broken off and then have JB Weld applied or so some other kind of welding? Another consideration is the surface it bolts to is flat. One of the reasons I broke it is I had too large a gasket underneath and so was tightening with a gap underneath the bolt hole. I am using the correct gasket on the replacement part.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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RayJohns

#53: Post by RayJohns »

That's a tough one. I'm not sure if JB Weld would fix that or not. The part could just be a write-off at this point, short of TIG welding or something.

I think to effectively glue it (i.e. with JB Weld), you probably would have to break it all the way. At that point, I'm not sure if JB Weld would be strong enough to repair it.

Ray

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drgary
Team HB

#54: Post by drgary »

The good news, though, is this machine makes great coffee that has almost ristretto thickness and lovely flavor. Thank you Lucio (Lvx) for suggesting it! I am starting to learn the personality of the machine. This is another one of those mechanical era devices where the engineers played with the balance between the heating elements, the pressure relief valve that consists of a ball bearing on top of a little chimney, a group that is also the boiler for temperature consistency, a nice basket geometry, 51mm and deep, and a very good piston and spring assembly that delivers the needed pressure and profile to the coffee cake.

It has its quirks with tiny studs and nuts sticking out of the shower screen, a need to toggle between the 1000W and 300W elements (I'm learning that turning both on heats it fast but as soon as steam starts releasing in volume from the pressure relief valve, shut off the larger element), and a need to empty water from the boiler when done. I also must get used to a three hole steam tip that doesn't easily produce a swirling motion. (Later add: The three hole tip creates very nice swirling motion if I place it at the surface of the milk near the middle of the pitcher.) I've seen some suggestions for plugging a hole but will play with it first. With both elements on, steaming power is ample.

When I take it apart to polish the outside of the boiler, I'll reverse the location of the switches to match the instructions on the tag on the base. :oops: To delay further aluminum corrosion I've already dropped a sacrificial zinc anode into the boiler. Later add: And the top cap will stay a nice powder-coated black, which matches the handles anyway. It turns out the black powder coat was the original paint on this machine.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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drgary
Team HB

#55: Post by drgary »

Summing Up: Final Thoughts on this Lovely Veteran

This mechanical era machine is very well-thought-out for running at the right temperature. As with my Pavoni, I've left the heavy chrome-plated brass portafilter stock instead of trying to make it bottomless. This allows me to control the temperature of the pull between cooling the portafilter and varying the timing of pre-infusion.

Other mechanical-era refinements include:

- The simplest of pressure-relief valves, a small but heavy ball bearing captive on top of a vent.

- A safety feature on the lever arm where you must rely on the pressure of the spring once it's released. Pushing back against the lever has no effect. This prevents turning it over.

- The base is wide and stable.

- The spring is strong.

- Basket geometry makes a great cup of concentrated coffee.

- This machine does especially well with the Fellini move (see elsewhere on this site) and seems to like an initial lowering of the lever, then raising to start the flow of water, then lowering the lever again for a pull that shows much more resistance. This is even after releasing false pressure through the steam arm.

Some shortcomings include:

- An aluminum boiler prone to corrosion and with nooks and crannies where water can collect. There's a water release valve at the bottom right of the machine to drain out excess water per instructions on the base. I also help prevent corrosion through having inserted a piece of zinc in the boiler that draws ions instead of the aluminum. That's why it's called a "sacrificial zinc anode." I also avoid thorough descaling of anything but the actual lever assembly and cylinder.

- Other nooks and crannies where water can collect and cause rust, including where the rubber pad around the base fits on the edge and maybe where the base meets the cup containing the electrical parts. I counter this by keeping the base as dry as possible and by having had the machine powder coated instead of just painting it.

- A shower screen held on by tiny bolts with nuts on them. This sticks into the coffee cake a bit and means it needs gentle cleaning. I've fastened the nuts on the bolts with tiny washers and have bought extra bolts and washers in case these come off. Between shots I wipe the shower screen gently with a wet sponge instead of a hard group brush. I clean gently using Orphan Espresso's small plastic bottles, one filled with JoeGlo solution, the other with water, to rinse the group after use. I also use a natural sponge placed in the portafilter to gently backflush the shower screen and keep it clean.

- Fastening the sight glass and its gaskets is tricky. If you start to overtighten, the gaskets squirm out of place. And the bracket doesn't just align these parts. They must be held in place while starting to tighten them down.

- Even though the later Liberty model is still made by Cimbali, the parts are expensive. Used parts can be had through Orphan Espresso and individuals parting these out.

- And like other espresso machines where the boiler is exposed, this is not a unit to have within reach of small children, because it gets hot. However, the heat is mostly confined to the area of the boiler. The base is quite cool.

A possible shortcoming is the immersion of the spring in the boiler water, where it can collect scale and maybe rust. However, the machine has a water drain tap and its instructions caution users to drain water out instead of keeping it filled. This helps prevent scaling and rust. When I first got it, the spring looked in great shape, so it may be a high quality stainless alloy. To fully drain the water out, you'll need to allow air into the boiler. I've done this by opening the steam valve and then loosening the boiler cap, and also by raising the lever. Probably opening the steam valve is enough. The important thing is to drain all possible water out. And whatever you do, make sure you release pressure through the steam valve before loosening the boiler cap.

Overall, though, I'm really happy with how this project is turning out. This is a lovely looking, vintage machine. Because of some of the shortcomings listed above, if you have the know-how to operate and maintain it you can find one of these used and functioning well for bargain prices. It has its own personality for making great espresso drinks that are sumptuously rich and chocolatey, and it has powerful steaming capacity. This one's a keeper! :D Edit: Or so I thought until I brought home a two-switch La Pavoni Europiccola and my wife questioned whether I'm able to sell any of my vintage machines. Only seven machines? That's not many by H-B standards! :lol: Anyway if no one goes for it I'll be happy to keep it still.

-
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!