Home Lever Machine Rebuild: Cappuccino Amore

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

#1: Post by MrGeary » Mar 15, 2013, 12:34 pm

Greetings forumites, this is my first post.

First, let me get some confessions off my chest. My name is Ryan and I've been using a Mr. Coffee steam toy and whirly blade grinder for over 5 years and thought I was making fairly decent espresso. Thanks everyone in this forum for putting me on the right path.

I decided to upgrade. Since I'm pretty handy with tools and rather cheap, I decided to fix up a vintage lever. So I recently purchaced a Cappuccino Amore on Ebay for $100 shipped. During the last few weeks, I've been researching online and purchasing all the necessary parts. During the next 2 weeks or so, I'll be rebuilding the machine and posting the progress on this thread.

I think I've found all the information I need to get this done (mainly from this forum ... thanks ... and from Orphan Espresso). I may have a few questions along the way, but this thread is mainly to just document my rebuild.

My appologies, but I forgot to get a decent "before" pic of the machine.

Here is the machine taken apart and cleaned. I boiled the parts in some dilluted vinegar, then cleaned them further with some bar keeper's friend, a mild acid.
Image

Just like everyone else rebuilding a Cappuccino Amore, I need to decide whether or not to machine a new piston to replace this gross corroded one. I'm going to machine a new one this weekend, I think.
Image

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crazy4espresso

#2: Post by crazy4espresso » Mar 15, 2013, 12:45 pm

Hi and welcome to HB. Nice little project you've got there. I wasn't aware that those pistons were prone to such corrosion! Looking forward to seeing more pics of the build. Good luck.
"I would rather suffer with coffee than be senseless." — Napoleon Bonaparte
LMWDP #427

MrGeary

#3: Post by MrGeary » Mar 15, 2013, 1:26 pm

Wiring design:

I tested the machine before I took it apart and it seems to not have any temperature control. It just got hotter and hotter and the pilot light never turned off. No big surprise, since the thermostats appear to be water damaged. Here is a "before" pic of the wiring:
Image

This is an earlier model of the Cappuccino Amore that has some sort of temperature probe inserted into the bottom center of the boiler. The probe is connected by a bare solid conductor to an adjustable thermostat in the front of the machine. There is no direct replacement available for this part, so I need to find something else. (There is also a standard external thermostat on the bottom of the boiler, which is a high temp cutoff for safety, I'm guessing.)

The later Cappuccino Amores have dual external thermostats on the bottom of the boiler and a simple "Hi/Lo" switch on the front of the machine. Here is a schematic that I drew up, based on my examination of the wiring photos on this webpage:
http://www.francescoceccarelli.eu/Macch ... mo_eng.htm
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It's a good setup that can easily be recreated using some cheap KSD301 thermostats from Ebay, but this isn't what I'm doing.

Instead, I'm going to spend a few more bucks on a PID system. Here is my schematic for that:
Image

It's basically identical to the Pavoni PID wiring diagram done by RayJohns, seen here:
La Pavoni + PID = better temperature control?
except I added a cheap thermostat switch between the PID and heating element for safety, as recommended by the PID instruction manual. And I added details on how to wire the power and pilot lights, since that was confusing to me at first.

I'm no electrical engineer, so if anyone sees any glaring errors that will cause explosion and/or fire, let me know now please.

MrGeary

#4: Post by MrGeary » Mar 15, 2013, 1:40 pm

Thanks for the welcome, crazy4espresso. The piston on my machine is slightly worse than others that I've seen online, but all of them show this kind of corrosion. It must be made of the cheapest aluminum ever or maybe even (gasp) zinc. I'm going to machine two new ones probably, one from copper and a one from aluminum. (I'm borrowing my coworker's lathe and that's just the easy-machining material that he happens to have on hand. Bronze would probably be ideal, though).

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peacecup

#5: Post by peacecup » Mar 15, 2013, 2:01 pm

One critique I've heard of these machines is low brew pressure. This would be due most to the large-diameter piston. If you find the shots seem weak with little crema, adding a second spring might be worthwhile.
LMWDP #049
Hand-ground, hand-pulled: "hands down.."

MrGeary

#6: Post by MrGeary » Mar 15, 2013, 2:31 pm

peacecup, yes I read that on some other threads. I'm modifying the piston geometry slightly to increase the spring compression a little. It probably won't make a noticable difference though.

It's possible these other Cappuccino Amore owners just had some other variable not right. Once I put the machine back together, I plan to try to calculate the pressure. I figure I just need to measure the force required to pull the lever down, then using piston diameter and lever arm ratio measurements, I can calculate the approximate pressure that the spring generates and see if it's anywhere close to the required 9 bars. I'll post my findings.

pacificmanitou

#7: Post by pacificmanitou » Mar 15, 2013, 3:18 pm

On a spring lever the pressure profile is often lower than 9 bar. Usually somewhere in the neighborhood of 6, and it declines to 4 over the course of the shot. If you're getting that then it shouldn't be a problem, but if you want to escalate the pressure, by all means do it.
LMWDP #366

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peacecup

#8: Post by peacecup » Mar 16, 2013, 3:19 am

Yes, calculating the piston pressure is a simple process if one has some basic physics skills (I don't). We've seen some rough calculations before. If the effort to depress the lever is equal for two machines with different piston diameters (accounting for the legth of the lever arm), then the smaller piston has the greater brew pressure.

As noted, home spring levers are said to operate at less than 9 bar, but I don't recall seeing any verifiable calculations of this (there may be some, however). Regardless, I believe the 9 bar rule doesn't apply to lever machines. Whatever pressure the Ponte Vecchio 45-mm group brews at, it tastes good to me.
LMWDP #049
Hand-ground, hand-pulled: "hands down.."

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rpavlis

#9: Post by rpavlis » Mar 16, 2013, 9:48 am

It is amazing that the piston is in such bad condition. What was it made from? Aluminium can corrode very very seriously. There are weird things about zinc too, it can corrode badly under some conditions too. I made one from brass stock. Brass should not corrode like that.

Modern 360 brass has less lead, I believe than earlier, but it still is 3% or so. You should still treat it after machining with the standard hydrogen peroxide vinegar mixture to remove surface Pb. It only takes a few minutes with a lathe if you make it from brass.

If the stock be aluminium, zinc, or steel, I would certainly not purchase another OEM one, I would make one from brass.

Ben Z.

#10: Post by Ben Z. » Mar 16, 2013, 12:46 pm

The previous owner of mine had a new piston made of stainless. Its a simple turning job.