Thermosiphon La Pavoni

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perfectwheels

#1: Post by perfectwheels » Feb 13, 2017, 2:37 pm

I've had this idea rattling around in my head for a few years now. I think it began with an auction of a La Pavoni Eurobar on Ebay several years ago. This was at the beginning of my obsession for espresso machines so the $700 or so it went for seemed a little out of reach. Obviously, I've learned better but I still wasn't willing to pay that much for the basket case that came up on for auction on Ebay recently.

Though, it did return my thinking to how great a home sized thermosiphon machine would be. I've owned many of the popular home lever machines but one of my favorites was a Sama Lusso. Club machines are great because they can be left on all day without overheating and are still very portable. The spring lever Sama was still a little too big for my kitchen, so it was only used for events. I eventually traded it for the lathe which makes this next project possible.

The Goal: a temp stable, plumbed in, hand lever machine that has a footprint similar to a Cremina, built with spare parts and home depot/Lowes plumbing supplies.

Starting with some brass rod donated by my friend Moshe.
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I drilled the rod and machined a sleeve to slip inside a pre-millenial group, while also machining for fitting attachments.
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I would move this hole a bit farther to the right for better clearance with the frame and compression fitting nut.
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3/8" compression fittings from Lowes.
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Cutting in half to save on costs. This was kind of a pain because it didn't leave much margin of error when brazing.
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Group with thermosiphon block and siphons silver brazed with Harris sil safe 56%.
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Cafe Amour boiler with siphons brazed in place.
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Cafe Amour steam wand.
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Deconstructed with fittings.
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Reconstructed
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Here are the essential parts brazed and ready. Next step is building framework to hold it all in place.
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perfectwheels

#2: Post by perfectwheels » Feb 14, 2017, 3:08 am

I was originally going to use a frame from an old maximatic I had laying around but decided I wanted the footprint to be just a little bit larger. I scavenged the cutoff bin at Pacific Industrial Supply for the metal...I think it was $11. The footprint is 8.5" x 13.5"

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Flex while pulling shots has always been a nuisance with the stock La Pavoni so I beefed up the group attachment area.

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Here you can see the group, pressure gauge and steam wand placement.

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Sight glass fittings from a Europiccola. I could have just hung the sight glass in place from the boiler but made brackets before I had thought about it too much. I'm too used to how a commercial machine is built.

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The fittings where machined so a 3/8" copper pipe could be brazed in place.

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This is going to be my first pid controlled espresso machine.

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Building a case from scratch is a fun puzzle but also a lot of work...

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Machining fixtures for the adjustable feet.

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The micrometer is overkill.

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They did turn out nicely though... Next step is fitting pipe.

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summer

#3: Post by summer » Feb 14, 2017, 3:54 am

:D NICE!

perfectwheels

#4: Post by perfectwheels » Feb 14, 2017, 4:26 am

Plumbing:

Because of the tight space and less than ideal planning in the layout bending the pipe 3/8" pipe was quite difficult. The 1/4" is a lot easier but still the tight space is challenging.

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After doing the sight glass, water inflow and steam last night by hand I decided to buy a cheap tubing bender today. Even so, the upper thermosiphon is an ugly piece of work.

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All plumbed and ready for a test run. I think I'll be reworking some of those lines but for now I'm more curious as to how well the machine will work.

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I haven't done any of the wiring yet so I just plugged directly to the element and brought it up to pressure. Only two leaks: one was a bad braze on the water inflow fixture and the other was the steam wand.

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The water fixture was an easy fix with some soft solder. I think the wand is fixed as well... The Amore uses a metal on metal interface similar to the La Pavoni. I chucked it in the lathe and sanded with fine grit... seems to be working so far.

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The good news is the thermosiphon works! It takes a quick flush to get it going on start up but once going it keeps rolling.

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I pulled three shots in a row with some pretty old espresso roast that was going stale in the grinder. The third shot was actually pretty good. I'm really curious to see how it behaves when I get the pid wired.

pizzaman383
Supporter ♡

#5: Post by pizzaman383 » Feb 14, 2017, 7:26 am

Very interesting project!
Curtis
LMWDP #551

User avatar
redbone

#6: Post by redbone » Feb 14, 2017, 9:35 am

Good work Larry.
I'd like to add this link for clarification to Francesco's site regarding the Eurobar so people do not confuse it with the Europiccola and Professional levers that most people are familiar with.

http://www.francescoceccarelli.eu/lapav ... ar_eng.htm

Internals - http://www.francescoceccarelli.eu/La_Pa ... 83_eng.htm

I like the thermal stability of the Eurobar lever especially when making multiple shots. The issue for me was the look, especially all that orange. Looking forward to your rendition.
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549

perfectwheels

#7: Post by perfectwheels » Feb 14, 2017, 11:46 am

Hey Robert,
Thanks for adding the Eurobar links. I don't usually like the look of fully encased machines either but for some reason that one does it for me...I guess it just screams classic 80's espresso... or something. Club machines are a strange niche. They seem to be super rare but not that sought after... it must be because their footprint is too close to that of machines with a commercial sized group.

dbvieira

#8: Post by dbvieira » Feb 15, 2017, 7:37 pm

something is wrong in your portafilter..is way to back left...wrong basket / Shower seal?

perfectwheels

#9: Post by perfectwheels » Feb 16, 2017, 12:40 am

very old portafilter gasket

perfectwheels

#10: Post by perfectwheels » Feb 16, 2017, 3:33 am

Wiring...

Last night I wired up a crude temporary harness so further testing could be done today. I believe the Amore heating element is 800 watts? The thermal couple threads into a brass well that was brazed in place of the original thermostat. Safety circuit from an Olympia Maximatic in case it runs dry.

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High/low toggle from an early 70's Europiccola re-purposed as an on/off switch. This idea came from someone's thread...maybe Drgary's Ultimate La Pavoni? I can't remember but a light went off and I realized why this cool switch was squirreled away.

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I'm going to move the SSR to a bit cooler spot and then build a shroud to keep any water off the pid and switch. A temp value of 117 seemed to keep the pressure around 1bar all day long. The deadband is much tighter than what I'm used to with a pressurestat.

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I left the machine on all day today pulling shots periodically throughout. I have a couple of compression fittings with slow drips and the steam wand is still dripping as well. The group though, remained very stable. After the initial flush the siphon did not stall and was able to produce consistent shots all day.

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This cheap and well used pid is good enough for holding a stable temp but not so great when trying to make adjustments. It is really slow to stabilize at a new temp setting. Does anyone have a suggestion on which pid is best for this application?


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